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to tb. euthoF. .lll dDLul,o! er9r.leit t! brlpDdt Lteatlh ion<br />
DerelqDlt FDer. ar6 thole of the arthc, aDit n|!t tlot le tala! ar<br />
tne oOCLdrJ. q|1!t6 of tha &stltuto otr !.mrtnlal !oalo6r.<br />
Frt ot tba.! paler B! fild€d ht ths D3lurtD!! of tba ttrtlrwt<br />
uDilr tJe UDt ,!it Lad Ole Catrlot (Del 4qr/.lo) alit t! DdrAlb.it<br />
rl,th tbB l|.td.s!lc sf tla Dqnr.tl.qt.<br />
a<br />
!i<br />
t
Content s<br />
Introductlon<br />
Paee(<br />
" )<br />
't-t<br />
lffoots of grazjne arlfuoals<br />
a) Eff€cts of the ani-na1 hoof<br />
!) nffects asdcpiated rith the oyoltng of cgaDl.c @tt€r<br />
o) Renoltal of nutrients ftlcm the lysten in tho<br />
ArdosL orop<br />
3-8<br />
8 - 12<br />
Effocts of agricultural. vehl-cl.e6<br />
15-16<br />
Eff€cts<br />
of hunan roorcation<br />
16 - 18<br />
Effects<br />
of tr€es a.nd. forestly<br />
,t8<br />
a) Sffects of trees<br />
a/ ltoot s<br />
14./ !a!to!<br />
b) lffects of forestry<br />
i) goil cohpactio$ anat di6tur.lance<br />
ii) Chan8es in the ruD-off eater<br />
ij-i) Reoollal of nutlieats in tl'Eber<br />
1A-19<br />
19-20<br />
20-4<br />
2t-24<br />
24- 28<br />
28-52<br />
Coepari8ob of<br />
oE th6 soi]-<br />
a) Iffects<br />
b) Renor/al<br />
anj-nal_6<br />
naterl.al<br />
the effects ol Brazla8 arrieals and. tree6<br />
on the soil<br />
ox l.oss of llutii€rlts frq the systeE llr<br />
or tihlor, in solutLon and a6 pattLculate<br />
52<br />
t5-56<br />
loLnow]-eilgsnent 6<br />
Append.ix (Draf.t Sueary)<br />
TabLos & &gfet€noss<br />
t6
Xany data are available on the effeots of Land-uae and management<br />
.<br />
on upland soils in general but few refer apeoificaUy to the Lake<br />
Districl; in spite of inoreasing public interest in the use of tb<br />
area d h g the past few decades. PearsaU '(19501, and more<br />
recently, Pearsall & Pennington (I 973) summarized available data<br />
aa soils, vegetation and land-use and pm~ided the relevant<br />
historical. background,<br />
Both publications stressed the beneficial<br />
effects of trees in maintaking and restoa %oil fertility and the<br />
effeclt of leaching of nutrients from the soil by the high<br />
miafalS which occurs in uplaxla amas in western Br5.W. Pearaall<br />
(1950) emphasized the loneterm nutrient extractive- effect of sheep-<br />
grazing whereas Pearsall & Pe-gbon<br />
m the ha-<br />
(1 973)' placed mom emphasis<br />
effeots of deforestation and the need for soil<br />
consemation in the M o Didrict, partiaulrsrly by re-affomataticn.<br />
Publicetion of Pearsail and Per-r&@on*s book stimulated the holding<br />
of a meeting of rapresentat ives of farmers, foresters, amenity<br />
organizations, conservationists, planners and -search aoientista<br />
in K d a l , Cumbria in October 1974 to identiQ and diacuas local<br />
soil pmb2erns.<br />
The meeting, t'Soila and ?dm in the Lake Matrict ', was<br />
sponsored by the Nature Conselvanoy Cowoil. One of the papers<br />
pmsented, mcarned with t ha eff eot s of woodland and forest in a<br />
historioal cmt&, ms gubEshed moerrtly (Chard, f 975). The<br />
present paper is an expanded version of another of the papers and<br />
is presented here for discussicn prior to final draft;& of a surraDary<br />
for the Countryside Cdssion (rlppendix bsl'm), It views soil<br />
as a resaurce and also as part of an ecolecal system of htemctbg<br />
parts.<br />
As a resouroe, -soil must be conserved, that is, used d soly<br />
so that it is maintained in a suitable o wla ion for a vafiety of<br />
land-uses ia the long term as well as Ln the short term.
As pa&<br />
of an ecological system, such as wmRUand or grazed graoshd,<br />
soil influences and is influenoed by otb r parts of the system fnolding<br />
the vegetation and thb animals whioh feed on it and, therefore' it cam&<br />
be viewed m~listically in isolation,<br />
Interantion of soil charaoteristios<br />
and veget ztian, topography, clFmate , land-use and managemen* ultimately<br />
moulds the landscape of an area,<br />
In pr~.ctice, each ecrological system change6 aonttnuouaw t uwarda a<br />
" -<br />
condition in mob the various parts and the rates of processes in<br />
the system are in an equilibrium determined by f~ictora such as olimate<br />
and management.<br />
men use or management is changed, adjustment of the<br />
sys,tem t o a new set of factors, input8 and outputs, my take a oonsiderable<br />
tim? and mey involve losa& and gains in certain parts of the system.<br />
he lattsr changes am not evidence of soil detedorrrtion unless they<br />
Wose major .Enitations on thy fit&<br />
purpose or qlesa they lead to soil erosion.<br />
. .<br />
use-.& the sail for some defined<br />
The areas of, partioubr interest in this paper Ee between the in-t;ensively<br />
managed arable land oP8 t& valley botf oms and the virtually sail-leas<br />
ana' unmnageab le high mountain t op s . They fall int o grade s 4 and 5 of<br />
the Agricult-1<br />
Land. Classification (Miaistry of' Agrioultum, Fishezies<br />
and Food, 1966) or classes 5 and 6 of the Soil Survey Land Use Capabiliw<br />
cl.assificatian (Bibby & Edackney, 969) and are classed mahly aa wo&W<br />
or heathland, moorland and rtxtgh land in the Second hd-Use Survey of<br />
Britain ( ~ ol~nm&n & &ggs, .1968), soils ~wg8 from mU-drained b m<br />
earths carrying krostis - Fevtuca grassland frsquently invaded heavily<br />
by Readtun on the lower fells to nutrient pour, af'tan peaty but mu-<br />
drained soils wlth Calluna and Vaaoinium or poorly aerated gleys with<br />
96ardw gmss2and on the higher gentle slopes, aagnant or non-#fag&<br />
bogs domted hy Edolinia, or Erioahorum reepeotivsly, occur on level<br />
araaa at most tiltit udei in the zone of ink amst, These are used
traditlonaly for rough grazing, forest~y, watcr oat- and recr*e3t%m,<br />
so their uao conaerna the geneml. public as well as landawnera and<br />
mnagers, particularly now as increased use of timber and high timber<br />
prices are encouraging the spread of comercia1 forestry, soci-econcmLo<br />
factors are favoudng changes in hill-farmhg and public pressurn on hill<br />
land is increasing,<br />
=th the above background, this paper has three mh 8ime. first, to<br />
sumarise the effgcts on so51 in gensral of the win types of land-use<br />
ad manag8mn-b found or likely to be found in the mure in the Lake<br />
District and to indicate tksir relevance to the soils of the area.<br />
Second, to compare the effects of the mjn Itznd-uses, prticularly<br />
CU-farmjxlg and foreatry. Third, 4s a basis for f'uture ma-h,<br />
to identie those aspects for mhioh relevant data are lacldng.<br />
Effects of arasiw animla<br />
Wny au-bhots, Coppmk & Cole- (I 970), Darling (1955), Hart (4 968),<br />
~cVeak & Loclde (1 969), Pearsall (1950), Pearsall & PeMtrgton (1931,<br />
Tivy (1973), tend to regard free-grazing aheep as harmtul to hill soils<br />
and ~e~tation anti hold the view that,by thefr selective close grazw,<br />
sheep suppress aL1 but the ccarsest plants such as mt-grass, Nardus<br />
stlicta, 8nd --rush, ' ~uncus aquarrosus, and by their treadhg they<br />
_I<br />
deatroy vegetation oover and thereby increaae the EkeEhocd of 8-dl<br />
eroeion.<br />
meep are also said to ooaplact the soil thus reduo*<br />
aeration, waf; ~r absorption aid dulat ion of nut dents , The culling<br />
of the flock is said to depbte meas of nutrients, parkioularly baaed,<br />
and thus to aocelerate the natural trend towards acidity h areas of high<br />
rainfall.<br />
for conv-ence<br />
together,<br />
Clearly, Pvany of these ideas apply also to hi11 cattle ao<br />
we mill cms'ider the ef'fecta of aheep snd oattle<br />
a) Ef feot s of the animal hod<br />
The diwct effaat of tmadbg varies with the hmf ares, the pressure<br />
exertea, the number of t-s,<br />
an@ the way in which the hoof ia appxed
to the ground per unit area and per unit tbm, the pattern of<br />
movement of the ani~lal w i t h an area and also the age, size<br />
and breed of animal.<br />
Available data on hoof measuremente and<br />
pressures exerted suggest that oattle tmad 2-4 times more<br />
heavily than sheep (Table 1 ) but such comparisons based on<br />
ext~polztion f'rom data for standing -1s must be viewed<br />
with great cadion bearing in mind results for standing and<br />
walking hbn (~ar~er et al., 1961 and p. 16).<br />
.r<br />
Moat stues of treadjng ef'feot or daily movemonk of animals<br />
have been carried out in lowland grassland areas and in emloaures<br />
where the animal may behave abnox'mally either because it is .<br />
stimulated to move excsssively or et a higher speed than normal<br />
(~amond, 1958) or because movements are wauoed *en ampLe food<br />
is supplied (England, 1954). . Data for individual sheep (Table 2)<br />
oombined with observations on the dajfy movement of upland flocks<br />
in hefis or home ranges of horn size (~unter, 1 962, for Cheviuta<br />
on mainly krostis-Pestuoa, Nardus and Molinia grassland and<br />
Ptoridium;<br />
--<br />
Gmbb & Sewell, I 974, for Soay &eep on Nardus, Mrosti a<br />
Festuoa, Holcus and a grasslmd and Cdluna) indicate a daily<br />
movement of 1.2-12.9<br />
hi with most values falling between 2 and 5 km.<br />
From such data, Welch & Cdna (pers, corn) oonoludad that the<br />
daily movement of Brit5sh hill aheep is about 2.5-5.0 km. CDnr<br />
parable data for cattle cover a range of 2.3-7.8 bpi day*'<br />
able 2).<br />
Hancock (1953), quoting varkoua pub=shed data, gives<br />
a range of 1 .&2.8 lan daym1 for dairy cattle end he stresaes that<br />
an 013 pasture or rough ground cattle travel twice as Phr as on<br />
newpastures, From a11 the above data one may comluds that<br />
cattle and sheep travel apprht-<br />
the saw dA&ance per day.<br />
b<br />
I<br />
Stride lengths in ahaep and cattle are respectively abmt 15 om<br />
andG am rams, 197.1).<br />
U~ling these data and appradmate maan<br />
daily movements of animals, Welsh & Cumins (prs. em.) oalculated<br />
that sheep a d cattle perform mspeoti~ely 100,000 and 4,000 leg<br />
movements animal-' day-' . kssudng hoof oreas of 15 am2 and
5<br />
2<br />
60 om respectively for hill sheep and cattle they calculated<br />
peroentage of range trampled per year with diffemnt degrees of<br />
aggregation of trampling and stookjxrg, Sheep averaged from<br />
1 .I tramples evenly spread over the whole area d th 042<br />
animals ha1 to 109.5 tramples<br />
on i@ of the area plus<br />
1242 trlamples on the remaining 9% with a mean stocking rate<br />
for the whole area of 4.0 sheep ham'.<br />
cattle ran& h m<br />
Comparable data fur<br />
8% bf the area tramgled per year hth 041<br />
animals hat and evenly spread trampling to 1 a trampled, 1 @<br />
21.9 times and 9% 2 .l+ times yearu' , here the mean stocking rate<br />
is 0.5 animal ha'. These calculations doMt Slowfor repeated tmsding<br />
of tho sme area duhg each tranple or for remcrval stook from<br />
the hills during the more severe weather, In most hill areas, the<br />
stooking rates for oattle tend to approach 0.2 -1s<br />
sheep fell between 0.2-1 animal ha'.<br />
ha -I iinqfor<br />
Compaction by animals is amcentrated in the top few oms of sou<br />
(wind & Schothorst 1 964; Edmond, 1 958 alth ougb acoaaionally,it<br />
extends to about 20 cms Pederer et al, 1 961 ) . Compaction nay<br />
be greater at s, few cms depth t kn at the soil s eace if the tap<br />
- few cms is highly organic and resilient (Hod +& Homrd, 1 976;<br />
Keen 8e Cashen, G. H, , 1 93 2).<br />
The overall degree of compactim<br />
varieowith soil oharacteristics. Sandy aoils lowin orgatdo<br />
mkter or dry soils fn general are little compacted, whereas soils<br />
rich in clay, peat and moisturn are very susceptible to trampling<br />
darrrage (Kind & Sc.Whorst, I 9&),<br />
Compaotion involves not mly an inorease in bulk density but also<br />
a mduction of soil pore space, aeration, moisture stom@ oapacity<br />
and infliltration rats, destruction of matepatable soil aggmgates,<br />
and changes in t herma1 charaoteristics (~dmund, 1958; Fedemr et a;L,<br />
4961 ; GfUrd, 1969; Gmdwell, 1960; L~I, 1959; Steinbrenner, 1951 ;<br />
Wind & Sohothorst, 1964). Such changes may be expected to lead to<br />
soil biological and chemical changes but these are diff'icult to
sepamte from changes associated with the effects of feeding and<br />
d~ and urine deposition and seen to be small relative -to the latter<br />
judghg by the findings of Floate (4 972). h!oreover, as Weloh &<br />
Cumins (prs. cm.) point outl the frequent occurrence of frost<br />
in British upand areas wili tend to minimize any trend t mzrds<br />
o ompaot ion.<br />
Soil eroaion asaociated with grazing does not appeGr to have been<br />
studied much in Britejn although eroaion gullies, which may be partly<br />
an effect of the grazing animal, ere seen frequently on hill graeins.<br />
Thomrts (j965) describes sheet zrosion beginning from '%urmstt or<br />
"kunkers" used by sheep as sheltering places in the Plynlimdn and<br />
other moorland amas of Wales and we hzve obsorvod fans of aroded sot1 below<br />
%bunkerst' an grassland on the lower fells in the Southern Uplands<br />
of Scotland, %he Pennines and the Lake Estrict,<br />
Anohtier aspect<br />
of erosim is the slow downhill movement of soil, Thonaaa (1 959)<br />
mentions the movement of a prticular sheep-path two feet downhill in<br />
four years, but in such exaqloa dinuntanglement of the effects of Mart,<br />
effects of' the animal, and natural dovn-kill soil movement is dif'f'icult .<br />
me effect of the hoof is more pronounced an wet soils, where the animal<br />
tends to slip and slide mom than on dry soils,<br />
The sod which protects<br />
the soil surface ia broken more easily by cattle than by sheep because<br />
the former exert the groat er hoof pms sure (~abla).<br />
In New Zealand, &ere soil erosion is rccognised as a problem associated<br />
with grazed, hill-soils, Gibbs (I a) has outlined the variou,: types of<br />
erosion which mcur and stressed the need for assessment of permfaaible<br />
stocking densities on particular soil types.<br />
These and other oomments<br />
, rvhi.ch he makes,appear to be relevant to soil coneelvation in the Lake<br />
District,<br />
New Zealand work h s also shown that vegetation, e.g.<br />
som gmssland<br />
with clover, my be considerably damaged by treading, particularly<br />
when the soil is wet and sheep densities are high (7-50 ham' )<br />
(zdmmd I 958; I 962; 963). Damage alone reduced herb&@ yield<br />
to as low as one eighth of the cat rol value.<br />
In the Lake<br />
Pistriot, because of much lower overall shoep densities, s~oh<br />
damage and also soil omp~ction are probably em11 oxoept on<br />
or near sheep-paths and o~e~ght resting sites on areas<br />
of the most palatable vegetation, A~rostis - Festuca grassland<br />
(~ughos et al., 1964; Hughes et al., 19E; R m s Bcweloh, 1969).<br />
In such places, changes in sward composition.are likely to #cur<br />
as a result of variation between hefiage species in resistace<br />
to treading (~ates, 1 935 for &ed<br />
grasslands on various soils;<br />
Ebond, 1958, 1962, 1963 for sown grasslands with clover),<br />
Grasses<br />
are mom resistant t o tmmpling t ha species such as hfyricc gale,<br />
~teridi& aquilinum an3 Vaccinum myrtillus which are undesirable<br />
to Evestook (~rama, 1971). Changes in the composition of the<br />
sward also occur when grazing pressure is insufficient to lead to<br />
severe treading damage (welch, 1974; Welch & Cummins pera. camm. ).<br />
Bny changes in swad coqosition produce changes in the type andor<br />
mount of plant remuins returned to ths soil and thus may lead to<br />
chavlges in soil chemical, biological and physical characte~s~ica<br />
(2p.3 - 12).<br />
From the above com~nts, the tr~edin~; wiucl Eapperlrs to ba ermtimly<br />
harmful. to the grazed s w~d-sail systen however, Daviea (1938)<br />
considemd that a small amount of trampling helps to break up<br />
and aerate the soil aurface and to earth up the bases of grassland<br />
plants. Some farmers use light trampling on a roseeded hill<br />
pasture in the belief that it has a firming effect similar to<br />
that achieved by using a roller (~eaould, 1 974). Miles (4 973),
8<br />
worEng oh heather moor, birch and pine wodland and jmiper<br />
scrub in Invmnesa-shire, f'outld much higher dansitf es of self-<br />
sown aeedxnga on soil bared by deer trampling than rm<br />
vegetation-covered soil so perhaps trampling is important<br />
locally in croat ion of niches for now apecies in a closd<br />
c o d t y ,<br />
Crocker (13 3) coneiders th~t<br />
heavy grazing<br />
creates vaccnt niches which are occupied by less palatable<br />
species from within or outside the community and this applies<br />
also to low levels of trampling (~ddls& Greig-Smith, 19~b).<br />
However, Ploate et al., (I 973) and Jonez (4 967) find t kk graaea-<br />
olrt species are not neoessarily replaced by unpalatable species<br />
(FY* 8 - 12).<br />
Published comenta on the effect d trampling<br />
on vegetative reproauction of pasture species are c onflictiq,<br />
Davies (1 938), Pearsall (I 9501, and hwes & Wolch (1 969) state<br />
that treading plus grazing promotes the tillering of grasaes<br />
~herea~l Eamond (I ff8) noted a progressive reduction in<br />
tillering of ryegrass and node f omation by clover as .<br />
at ocking density increased from 0 to 8 aheep ha-' .<br />
. b Effects associated with the cycling of organic matter and<br />
nutrients within the animl-ve~etation-soil systm<br />
On ungrazed hill-land, plant material produced above and below<br />
ground eventually dies and, as it deoays under the influence of<br />
aoil bacteria, f'ungi and animals, the nutrients which it cmtains<br />
are relecse2 and eithzr held in the aoil or re-absorbed by<br />
plants, or loached out of the ndl. . This leaching is moat<br />
pronounced where rainfall is high, as in much of western<br />
Britah, and whore the plant remins produce substances suoh<br />
as aoids and polyphonols which promote movement of materials<br />
down the soil profile. Basos, are amongst the nutrients whioh<br />
leached out, so the plant remins, tond to became
progressively =ore acid.<br />
This acidity, combined with the<br />
lack of readily-available<br />
.. niltrient; and the low te~erat~s<br />
prevalent in hill areas ~.-e striot s the numbers and activitiaa<br />
of ~econposer -organisms, so deconposition proceeds slowly<br />
wd formation of a mat of plnnt remains and/or of peat occurs,<br />
The imposition of' regular grazing on the system described above<br />
involves defoliation, damga to the plant by trampling and<br />
soil compaction md hence usually lower herbage prduction<br />
(Bryant et al., 1972; Xdmond, .t958; Floate, 1972; h w a<br />
&%lch, t969) and root growkh (~chustor 1964).<br />
This,<br />
toge5her with digeation and assimilation of some material by the<br />
anbal, reduces the mount of organic matter retuned to the<br />
soii. In a paired-plot fence-line study in Scotland, Flmte<br />
(1972) found that imposition of grazing led to a roductiori in<br />
the thickness and amounk of aurface organio matter. Howard<br />
& Ho- (1974). working on A~rosteFes hucetum Fn the northem<br />
Permines, found no ohange in the amount of surface organic<br />
remains with grazing but sug~sted that in the absence of<br />
,gazing much of the dead grass is supported by the live<br />
veget~tion and hence waa not collected 3n their soil cores.<br />
If overstockhg mcurs, herbage m ill be so reduced and<br />
damaged that bare aoil ~ 1 appear, 1 The latter is highly<br />
susceptible to erosion and is also exposed to sxtmmea of<br />
temperature which my, on balance, be unfavourable far<br />
microbiological actlvity although mode rat ely high temperat urea<br />
favour high activity if moi~turo dae~ not become limiting.<br />
Grazing involves channelling sme vegetation tkroue the<br />
and baok to the soil in droppings and urine, The benefioid<br />
effects of dung and urine on soils and vegetation are wellknm<br />
but quantitative evidenoe of their influence on'nutrimt<br />
oyoling is leas well docmente&. Floats (19 72), in
laboratory incubation studies, compared the release of<br />
nukrients frm (A) pl--it zakeri-1 cut in October and (B) fc*<br />
ous produced by sheep fed the same mterials cut at monthly<br />
intervals Prom May to October. He found that readily<br />
available nitrogen (N), inchding urine N, increased from<br />
31.5 for A t o 52.7 kg ha-' for B for krcstia-Fesf uoa<br />
a d 12.0 for. A to 18.4 for 3 kg nal for Nardus in spite<br />
of herbage producLion decreases of 6% for A and 24% for B.<br />
Similar reault s were found for phosphorus (P)-<br />
He also<br />
demonstrated increased uptake of N and P fim dung and urine<br />
by the pasture plants,<br />
Clearly, gr~zing speeds up the<br />
nutrient circulation in the surfaca soil./vegetatiun system<br />
and this more rapid re-use of the small amounts of available<br />
nutrients present in hill soils can be interpreted aa an<br />
jndication of improved soil fertility,<br />
In his fence-line study, Floate (1972) found that grazing led<br />
to:<br />
i) Reductions in the ratios of c.rrSon (c) to N and P for phnt<br />
rewins and of soil to 4O cm depth. Such ratio& are<br />
often thought of as indicatcrr s of soil fert;iUty.<br />
a) Increases, in b &la total and organic P but no significant<br />
ohange in the concent ration of available P in the top 40 cm<br />
iii) mPn herease in soil pK but not in base saturation,<br />
Howard & Howard (1 976) recorded higher nitrogen cronteflts and<br />
a lower C/N ratio in the top 3.5 cm of eoil Kith grueingn<br />
bspi rntory actidty of the soils was higher on the ungmz#d<br />
area, probably as a result of conversion of herbage to faeces<br />
with a lower mspiratory activity (Floate, 1970). During<br />
& Radoliffe (1962) found th~t the top 4 cn of the duneenriched<br />
soil of sheep-tmcks on hills In New Zealand had is. higher C
content, a mch higher N content, and a lowor GIN mtio<br />
than other soil on the fill.<br />
The above comments refer to nutrient cyoling in unimproved<br />
3051s. If lime andor basic slag are applied on a grazd<br />
area, mrked increases in aoil fertility occur *om enhanced<br />
decomposition, reduction of cat formtion and improved base<br />
status (Shaw, 1 95 8).<br />
Liming and other soil am el ioration<br />
treatments are usually coupled with increased atooking.<br />
This leads to a f'u*her jncrease in the proportion of th@<br />
herbage production which is chamellad through the anid<br />
alld a firther reduction in the mwnt of decomposing herbage<br />
on the soil surface loat ate, I 970, 4 972).<br />
It also leads<br />
to hcreaeed utilisation of relatively unpalatable species<br />
and ult-tely<br />
a change in sward composition towards dminance<br />
by more palatable graminaceous sp~e5~9. Plate et al.<br />
(1 9'731, for exaple, showed f hat e Nardus sward oauld be<br />
changed to a palatable gms s-dominated sward using oatrolled<br />
intensive grazing i l ime + NP + Potaeaium (K) + awface<br />
seeding, but at R high cost.<br />
1-e sult s in Xale s .<br />
Jones (1 967) obtainad sindlar<br />
From the soil consemation viewpoint, if shesg are to be kepk<br />
in kigh rainfall areas, a management regime is requimd wfiich:<br />
- . .<br />
i) maintainsacontinuousproteotive coverof palatable<br />
hsfiage plants and asswiated plant remains<br />
+<br />
) maintains the soil in as fertile condition and 'rPith<br />
as good structure as possible.<br />
Qhese requirements are at levst park- met by the H.F.R.O. '8<br />
prwosals for a t w-past ure systea involving:<br />
- i) imprbfrelilmt of the part of tb available pasture nhioh<br />
can be nost acanmically improvd, that is, that on the better<br />
sails already oarqing soms %matis-Festuoa orbracken
12<br />
d m<br />
use of the herbage prductioll an U s<br />
by heavy intedttent cGopping<br />
area<br />
iii) h~avior use of the uni~roved area especially ahrig<br />
the sumer (~adie, Arnatrong Bc Wxmell, q973);<br />
This approach allovis m h heavier overall stocking with sheep<br />
and some cattle. The latter are less selective in their<br />
grazing thm sheep an& they c ontrol and reduce the coarser<br />
herbage species (Fenton, 1937). In field trials, mimd<br />
grazing has led to a higher output of sheep flesh plus a<br />
bonus of some cattle flesh (i'iamop, 1965) and my therefore<br />
be desirable on oconornic zs well as ecological grounds.<br />
In the Lake District, although the H.F.R.O.'s proposals have<br />
not been put into practice to any sppmciable extent,<br />
improvement a d 'nore efficient use of the lomr altitude<br />
grazing3 with better soils is favoured. In particular,<br />
the use of herbicides such as asulam for bracken is being<br />
tried. Soil changes resulting from such treatment s and fion<br />
associated practices, such ns reseeding and stockin& with<br />
oatt le, are currently undescribed,<br />
01 Removal of nutrients from the ~yst en in the animal crop<br />
Several authors have calculated removal of nutrients in the<br />
hi11 sheep crop per unit area per year. Comparable data for<br />
hill cattle do not appear to be available although Dean et al;,<br />
(1 975) calcuated removal of' nitrogen fron a short-grass<br />
prairie in northern Colorado by yearling Herefod heifera<br />
dang June-August Tho two grazing intensities used, 0.1 1<br />
and 0.37' - 0.48 animals ha1, are af a similar order Qo t hose<br />
found on British bill grazings and they led to N removall over<br />
.<br />
-?<br />
the three nanf;hs of mepsct ively 59.2 kg and 4 5 -4 kg 100 ha
Crisp (1 966) collectsd informtion on the nutricnt budget<br />
for an 83 ha peat-c o v ~ catc,tlment ~ d on the fdmr House National<br />
Nature Reserve is, tk-~ northam Bomines onrJrying about 4 8 shoep<br />
fYm April' t o Oatobur only (Table 3). Nutrient outputs in<br />
sheep were sna31 in relation to a) outputs in water =d eradiqg<br />
peat, b) nutrient ressnes in ths pat, c) and inputs in<br />
precipitation.<br />
lhoraove r, other studies indicate that<br />
precipitation contains only part of the total nutriunt input<br />
(PP* 29 - 30)* + RZemndar ('1974) indicc?tr3d +ha+<br />
-1 -1<br />
E3 fixation of the orfier of. at lsest 10-20 kg 100 ha yr occurs<br />
commonly on t undrdnoorland type sitaa in the Northern Hemisphore,<br />
Two out of five values for Pennine moorland mre excessively<br />
-f -f<br />
high, 3790 and 1@9 kg q 00 ha yr .<br />
&wes (I 966) and hwos .& Welch (I 969) calculated nutriont removal<br />
.<br />
in sheep for the whole ErIoor lIouse National Natllre Resarve of 9850<br />
ha stocked wieh a masdnun of 8500 sheep from April to October<br />
..(Tabla 4). hires (1 966) also cdoulated omparable figures for<br />
the Lake District, assuming a stocldng density of 2.5 han'<br />
a:&mq&out the year able 4). In tkc absurce of other<br />
conpsrable output data we havo compared these loesas with the<br />
nutrient input o pub liahcd in p wcipitation for the Lake Di st ric-t;<br />
(Table 4).<br />
Data for both areas emphasize the nutrient renova1<br />
in sheep in relation to nutrient input. Supporkin-g data are<br />
also available for other areas. Jmes (4 971 and pers, corn,)<br />
and ~oberts & James (1 972) reporting work done on a R. %ye<br />
catchment of 2043 ha in the Plynlinm ares of %ales, eatbated<br />
that 5060 kg 100 ha-lP-' of calcium (Caf was removed<br />
4 -1<br />
in tho sheep crop of c. 2.5 sheep ha yr , whereas atreamat er<br />
output was 2930 kg 100 ha-' and input in pooipitation was<br />
-1 -.1<br />
5mkg100ha yr . Flonte (pers.oomo.) estioatedfhat,<br />
t-g a high estimate of 2.5 lambs (900 kg, 0.s P) produced<br />
per acre of Scottish hill land, less than 20 kg 1CO hanq of<br />
P are removed mually from a soil nutrient pool in excess of
200000 kg 1 M) ha-'. Grant (pars. o ma. ) otllculitcd that<br />
1.6-72.0 kg potassium (K), 9-72 kg Ca, 5-40 kg P and 3 - 240<br />
kg N 100 ha-'<br />
was removed fro^ the Scat tish hill ooosyatcm by<br />
a a le of lads and cast ewes rvith recpectivcly 0,5-0.66 waea<br />
ha-'<br />
and 7% lambing success and 1-2 owes hh' and 100$6 lilmbing,<br />
King & fiichols on (j 964.) e st j-mated that nutrierit removal in<br />
sheap prducts in Scotland amounted to 22 kg Ca and 11 kg P<br />
103 he-' with 0.625 sheep ha-' ,<br />
Althorn the above calmlatiuns vary in c*~?-lyticyl d-:kc umd<br />
and in the rhtio of weights of. -sheep cczrcase .to wool, sheep<br />
consistently appear to remove small anounta of nutfie~zts :but<br />
+,his stcltecont I'L quirb s thm~<br />
qu~llif'icakions.<br />
1 ) As mny authors hzvo shcim, sheep are highly selecti vo grazers,<br />
so fiutrient rcmovnl is conccntr;:ted on the most palatable<br />
parks of the sward particuhrly A ~ r o s t i * w grasslad.<br />
The latter my comprise less than 2%<br />
of e mixed moor<br />
in the Pennin~s (hies & Welch, 1 969) with 2.2 sheep hav'<br />
but my support an averege of up to ~bmt 9 sheep ha-'.<br />
This is in the range of 5.6-18.2 ewe units ha-' found for<br />
similar grassland in Wales (Hughes et a1 '1964). Assuning<br />
9 sheep ha-', then the loss of P in sheep at Moor House is<br />
about 29 kg 100 hn',<br />
c* 5% of the input in the rain,<br />
vhcreas for the Lake District the P loss would be abaut<br />
30 kg 103 hdl, sirr&lar to that in precipitation. Fiannop<br />
(I 965) exprcsaed some doubts about the ~ bility of Scuttish<br />
hill soils to replenish the P rensoved h sheep.<br />
Smila~<br />
aoubts my also apply for P and other nutrients in the Lake<br />
District for the areas of more palatable herbage,
2) A high percentage of soil nutrients is not readily<br />
available to plants, particulwly in the mt , acid,<br />
leached crganic soils of the Lake District, either<br />
because, nutrion Es are in resistant or~anic mztter 'in<br />
peat, or in soil horizons below the rooting zone, of<br />
herbage species. Perhaps t h rzte ~ of removal of<br />
nutrients in sheep ought t o be related to tho rate<br />
at which nutrients can be supplied to herbage plats<br />
from the rooting zone rather than to the total soil<br />
nutrient pool.<br />
Although Rams &kdelch (1969) gathered<br />
a vast amount of data on the sheep arid vegetation at Moor<br />
House they mere forced to state that .,..I1<br />
as little is<br />
known about other factors such as uptake of nutrienks by -<br />
roots at hbor House, it is at praaent inpossible to<br />
de-terruine whether individuu swards or vegetation types<br />
are declinir,~ in their stock of minerals and nutrientsn,<br />
3) Although levels of removal are currently low in relatio&to<br />
nut liont a in precipitation, this fact doea fiat necessarily apply<br />
during the psst few hundrod 9 ers.<br />
In this period not mly<br />
is the record of sheep densities inoomplat& but also data<br />
on nutrient inputs are 1mlcing.<br />
Composition of precipi-<br />
tation is known tc v~ry with the because of factors suoh<br />
aa changes in air pollution and d nd direction,<br />
We 'canncb<br />
therefore assess accurately the imporbance of removal of<br />
nutrients by animal a in the past.<br />
Effects of agficultuml vehicles<br />
Damage to soil and vegetation by wheeled and tracked ~ehiclea may be<br />
conaidexlable on and around well-used tracks especially where the soil<br />
is wet. The effects include many of those already mentioned in<br />
association with trampling by animls,
Pressures exerted on soils and vegetation by agricultuml tr
Bayflel,n (197J) in{ioated paco longthB o? r5-7t ott for $alLera on Scottioh<br />
bj.U path8. lJreso velues ar.e con6ider€tly lalt€r than tho6o for sheep<br />
o! cattLe (15 ".d<br />
45 cir !. /r. ). Further dil.oct co@lerisoo botwegD<br />
prE69u!,ea ex€rtod or. anoas couFactetl by grazlng aninsls anil Man i9 d.ifficuLt<br />
because of ilifforonoes 1n locoootion and 1n loceotorla bghavlou! ardcucrent\y<br />
LEpolsille because of laak of suitablo alrta fon: use of peths by<br />
sb66p ald oattlo or eve!6ge us6 of rhole areas ly !ran.<br />
The effoot of tr6.e!!ing by Mar1 dr soil anal vegotation has been mrc,b<br />
d.ocuDented ani. discusseA (Lid.dle, 1975, Lu11 1959, llarlen 1974; Speight,<br />
197tt cf atso pp. J - 8) so only ell outtine of the iJ4)e6 of chaEgps<br />
rehj.ch occur rcill bo given here. Chsppel1 (19fl) rorting on chalk<br />
gre.lalanil, foubd that as trpepllng lncreaseal th€ so1l bulk d.ensity<br />
i,Dcreased. anal ra.ter stability of soi.1 aggregates, soil noiature co.'ltent<br />
aatl !tu&!era of soil ani.uals all alecredseil. Ch€4ica1 change6 rBre not<br />
6iSnificant<br />
or cou]-l nct be testeil becaus€ of bulkfutg ctr sa!0plos but<br />
tenal€noies exi.sted. for increasea l-n pet'cebtag€ of ir'on in th6 rgduced<br />
(terrous) fotro, aEolurt of a@oniun l{ and peqc€ntage total N and. aearpaae!<br />
Lr1 s.eoturt of bitrato, perceotage or8anic C ard C/N tlatio. StoLla! C<br />
and N t!"onas l{etr folrna on sheap-paths by D:rj.!!g & naac]-iffe (1962).<br />
ooElosLtion of the sward. charges conaid€lably<br />
gn heavll.Jr tt'anpled. aleas<br />
(Bates 1915; Bayfi€ld., 1971 ; Chappelr, 1971i Daai,es,'19J8; Liddle &<br />
Br.8tgL.sdth, 1975t). This has beeo attriluted. to dlffer.enoos in tbe<br />
rEsistenco of diffsl9trt speoies to physical daaago (e.g. Bafoa, 1915)<br />
and, in tho responso of different<br />
er8. soll rooisture status (LiddJ-e & erei.g-SEith,<br />
s.trFcieg to changed soil ooDilLtlong<br />
19Db) or soil<br />
tenpeletu'€ (Liad.b a Mooft, 1978). Vogetatlolr oover usually alecr€asos<br />
with tmnp1ln6 (!atos, 19r5) lut veeetation dj.v€roity es.y alecr€ase<br />
or i-ncrease d.opendtng on trenplln8 intonsity ana initial condition of tho<br />
!€Betetl-on (Irtddfe, 1975; VtaLaE, 1971 and FI. 5 - 8).
Appreciable mechar~icel damage to vegetation leads to .duction in<br />
vegetation height (~iddle, A9751 and in the dxy weights of #daX<br />
parks of plants (Duffey, 1972) although Lfddle and Greig-Wth<br />
(19~b) indicate that low levels of trampling at, for example,<br />
path margins, may stimulate p roducti on.<br />
Any change in the t ype<br />
or amount of live or dead plant material in or on the soil is<br />
likely to lead to changes in the mLcroclimate around the soil<br />
surf'ace (Liddle & Moore, I 974) and in the soil biology (Chappell,<br />
1971; may, 49731.<br />
Damge to soil and vegetation by skis and wheeled vehicles my be<br />
oonsiderable and continual locally and include many of the. effects<br />
associ&ed with trampling by Man and animals (sayfield, 1973a, 1973b;<br />
Lull, 4959). Pressurss exerted by a family cnr amount toabouk 0.95 kg<br />
-2<br />
cm on soft ground or 1.5 kg cm2 on hard ground, that is about the<br />
same as p-ressuros exerted by the uheep hoof (Table 4 ),<br />
In the Lake Disk rid, comercinlly oqaniaed skiing, except for<br />
sdl amount of grass-skiing, has not gained a foothold so the<br />
major effect a of associated construction works (~ayfield, 1 973a3<br />
are not seen. Tiheeled vehicle damage, including that resulting from<br />
use of motor-cycles an the fells (~riends of the Lake District, 1975),<br />
appears to be slight.<br />
Effects of trees and forest=<br />
a) ~ffects df trees<br />
Forest soils exhibit peculiar charactsriatics acquired under.<br />
the influence af three soil-forming fautors uncommon in ather<br />
soils - tree roots, forest littor and apecifSc organisms<br />
whose edstence depends on the forest vegetation (~ilde, 1958).
TI will consider the effects of trees under only two headings,<br />
i) roots ii) litter. SQil org~niams are associated a.kWy with rooks<br />
and plant remaim and will theref ore be discussea briefly under bOth<br />
he acting s .<br />
The soil-atabuzing action of" tree rods is w11-known<br />
(~ournier,'1972). In many U s District woodhnda on steep<br />
slopes, an acornlation of soil and/or atones and moat<br />
advanced soil profile development occurs on the upslope side<br />
of tree bases or of the main swace roots,<br />
th~t trms<br />
This Sldjcatas<br />
am inhibit hg saw downhill sail ~ovement but<br />
that they are not preventing this navement entirely.<br />
Clearly,<br />
Chese observations do not iniiaate that trae roots are preventing<br />
soil erosion which would have occur-red in the absence of tmea.<br />
The distribution of tree roots in the 803.1 depends partly<br />
on tree specibs and partly on soil characteristics. It<br />
used t a be thought that certain species, for example spruces,<br />
wen typically shallm-rooting whereas others', for example<br />
pines a d many deciduous trees, =re deeprooting. This view<br />
has now been largely discounted and it is becdng clear th~t<br />
m y<br />
species can adapt their rooting form and depth &en<br />
infl~noed by soil characteristics such as shallow depth,<br />
stminess or a high watertable (Strtton, 1969).<br />
%em roots come into contact with rock they appear to<br />
cause appmciable physical disintegration and chemical<br />
mathering.<br />
Kla~lsing (1 956), for example, suggested that<br />
in a beech wood granite and diorite weathered at rates of<br />
respectively 1 .2 and 2.1 mm year"' . Evidence of weathering<br />
in forests by the action of acids leached f'rom okgao
mtedals, by carbon dioxiae produoed by the rwts and by<br />
the action of soil micro-organism is reviewed in Lubz 8e<br />
Chandler (I 946). Voigt (I 965) and Wed, Davey & Cook<br />
(1969) give further det~5ls;<br />
Ons of the mnin functions of roots is absorption of water<br />
and nubdents from the soil. The wcorhiaal f'unej. growing<br />
in and around the root tissues helps the plant h the absorptian<br />
of nutrients, particularly phosphorma. bhen a root dies or is<br />
killed by felling of the tTee the organic matter, it cantahs<br />
is slowly deoomposed by the joint action of ad1 baoteria,<br />
hgi md soil animals and the contained nutrients are released<br />
alowly hto the soil, The presence of root chamnels 5n soil<br />
re&ers the latter more permeable to air and water whereas<br />
organic mtter from root decomposition helps to maintain the<br />
hwa level throughout the soil profile. These effeota are<br />
par*t;icUrly important in an area such as the W Dis tr3ot<br />
where the high minfaI.1 tencla to Bach the soil of nutrients,<br />
and deep-burrowing earthworms are often abserrt beoause of hi&<br />
soil a-ty.<br />
a) Litter'<br />
Utter, the fallen dead branches, le~ves, flowers and frufta,<br />
acts as a blanket or: tho soil surPace protecting the underlStjng<br />
soil and the roots an& soil organisms it contaim againat<br />
extremes of tempemture, direot insolation, and the direct<br />
impact of rai~ and restrict jng eveporntion *om the soil.<br />
The nutdents in litter can only beoome available to plants<br />
by deoompositian of the litter under the influence of<br />
numerous dZffeerent types of soil arganisms.
Litters differ in their oomposition.<br />
Some, such as many<br />
coniferous litters and beech, have a low lime and nitrogen<br />
content but contain relatively high amounts of acidio<br />
materials, gibre and polyphenolic bornpounds , whereas<br />
athers, such as ash or elm, are rich in bases and n5trogen<br />
and low in acidic material and fibre,<br />
The polyphenolic<br />
ampounds inolude the tannins found, in large quantities<br />
in some tree barka.<br />
During senescence of the leaf or<br />
needle, the polyphenolic material in the cell sap interaots<br />
~5th the protein of the cell protoplasm by a prcxess sidbr<br />
to the tanning of hides,<br />
The presenae of tanned protein<br />
and of the other litter oharacteristics mentioned abovo helps<br />
to explain 57hy certain litters are leks digestible a d mom<br />
unpalatable to soil a m l a and more resistant to microbial<br />
attack than others (~andls~, I 954).<br />
Trees which prduce slow-dec mposing litters bring about<br />
a redistribution of nutrients in the soil prof'ile ~5th a<br />
concentration largely near the a oil surface.<br />
af nut dents may be imobili zed in plant remains.<br />
Large amounts<br />
Ovingtan<br />
(195973, 19621, for example, showed that, in a 55year old pine<br />
plantation, amounts of nutrients equivalent to 1% (~a) to 9@<br />
(N) of the nutrients in the standing trees were pre~lent b the<br />
plant remains on the soil surface.<br />
During percolation of<br />
min-water, nutrients are leached from the remains and iron and<br />
aluminium are noved down the profile under the hf'luence of<br />
acidic mterials and polyphenols from the If tter, the process<br />
of podzolization,<br />
obvious accumulctians of<br />
The mourrence of podzolization and of<br />
nutrient-poor Litter under<br />
conifer and some hardwood trees are perhaps the main reasons<br />
why some species have acquimd the reputation as soil<br />
".<br />
degraders, however, the justification for this reputation<br />
remaina ccncrwersial (Page, 1968).
Although the eWect of tree litter on scil is only partially<br />
understood certain points nrs now clear. Th@ amounts of<br />
bases, polyphenola and other mterials which affect soil<br />
profile development vary not only betvmen species but also<br />
within species depen&ing on the status and type of 3021<br />
on which the trees are gr&g (~ork, 1942; Coulson e'c al.,<br />
t960). This 5uplies that it my be possible to alter the<br />
effect of thc trees on the soil by altt!ring the soil base<br />
st3tus. Some species, for examplebirch, are ofken regarded<br />
as soil improvers (1)5&leb~, 1952; Gardiner, 1368) but this<br />
view has been challeqed and is still controversial (blulie,<br />
1956). One cause of such controversy is the tendency of<br />
some workers to focus thefr attention on the superficid- sail<br />
layera, -here some changes undoubtdly occur (0vh&oa, 1 P~J),<br />
rather than considering nutrient content, nutrierut; availability<br />
and &,her characteristicn of the &ole soil profile in relation<br />
to the +,me's requirements.<br />
Podzolization appears to be unavoidable under conifers on<br />
some sites inEurope. It is rapid and complete under pine on<br />
poor sands or under spruce on fietefiured soils wLch previously<br />
carried deciduous forest whereas on dho r soils it is only<br />
partial with inoreases in the amount of superficial plant<br />
remins, acidity and C/N ratio for humus rich layers<br />
(Faurnier, 7972). Blisck (1974) indicated a similar picture<br />
for Czechoslavakia where 20-4% spruce mixed w%th brmdleaved -<br />
trees caused no adverse effects on moist alluvial soils at<br />
100-200 m altitude and increusing percentages wrt: tolerated<br />
as altitude and rainfall Fnoroased until, at AIOO-1200 TI pum<br />
spruce produced no significant deterioration of brorm f orast<br />
soils. Productivity was roduced significantly if s too high<br />
percentcge of spruce waa plated partly because of soil<br />
degradation physically and inadequate nutrient availability<br />
and also because of high ht orception of precipitation by<br />
spruce dmng the grodg season. G e m v~orkers, in general,
also associate pcdzulixetion ~ t decrea~ed<br />
h tree productivity<br />
but Gensales morking in the Harz mowhains and Holmegwrd<br />
et d., in Dennark Fourld no reduction in timber vollllne prduction<br />
even ove-t. three generations of trees on the sane sites ;pith sli&tly<br />
pdzolized soils of unspecified types (~omlisr, 1972).<br />
Effects of fomstm<br />
%a main effect? of forestry include soil compaction ad<br />
disturbance associated with forestry operations, ohanges in<br />
mount and quality of run-off water, nhich has an obvious<br />
bearing on loss of soil nutfionts and particulate matter,<br />
and removal of nutrients in the tree crop.<br />
i) Soil corqaction and disturbance<br />
The mxhurn direct effect on thlj soil occurs dur5ng<br />
site prepamtion prior to plating when drainage oper~tions,<br />
ploughing and mawking sevsrely Listurb a d to sme axtent<br />
mix the soil, and during hamtisting when hsa.vy macbinexy<br />
movssinto the forest.<br />
pp, .t5-?6 a'bova indicate thensw<br />
range of pressures exertedby veUolas fi&Q to bcr used in<br />
fmests hovmver, as Lull (7959) points out, weight my not<br />
be very important as pronounced effects have been fmnd<br />
with small preaaures. Under met conditions, nacxoscopio<br />
pore space was mduced by half and infiltration rate by 8@g<br />
after one pass by a crawler tractor (ofpp, 1~16).<br />
? 0-26 of total area my be conpacted during tr~ict or logging<br />
but area affected can be much reduced by maximum use of<br />
rwds and of lcg slides or averfiead cable-mys.
B h s (Xersonal com~unication) has pointed out that<br />
evidence of effects of compaction on f'oraat pr~~uctfon is<br />
scanty*<br />
Youngberg (1959) examined the growth of Douglm<br />
fir seedlings in soils cornacted by tmctors during<br />
lomng,<br />
Growth was aignific&tly less on coqaoted soils<br />
coqsrutd with that on the apparently undisturbed soils of<br />
clear felled arsa, probably because of poor aeration and<br />
low nitrogen in the former soils. Porest soils in<br />
general are light a d e: aily comgacted (~ull, 1959) but<br />
they are usually little disturbed for long per5ods and are<br />
therefore able to mcwer frw severe compaction or<br />
disturbance w ith the aid of mtural biological and physical<br />
processes.<br />
fi) &awes in the --off<br />
water<br />
In British plantations, 1&5kc:/i of the incident precipitation<br />
fails to reach the ground because of interception by the<br />
tree canopy and only 0.w-0.32"/0 of the t &a1 flows down<br />
tho atems of trees (Ovh&on, 1954). Trees therofom<br />
reduce considerably the amout of water available for soil<br />
leaching and also the direct impact of rain rn the soil.<br />
Appreciable quantities of water which have been taken up<br />
by the roots are lost via the leaves as traspimtion.<br />
As a result. of interoeption plus trznfipimtiorq tree s<br />
8speciUy conifers, tend to dry out the soil. This is<br />
seen ,best in the shrinkage of peat soib aftor aff'orentation<br />
(~inns, 1968). Trees also reduce run-off wter to only<br />
28-5% of incident preoipitat ion, conifers tending t o give<br />
lower f5-s than hardwoods (Ovingt on, t 962).<br />
Compafisons of' total evaporation from forest and grassland<br />
or of water yield from f 0-st<br />
givon variable msult s<br />
and grcsslund catchments have<br />
u utter, I 968). This variEtbility
25<br />
is associated hith variability in the pattern of rainf'a.ll<br />
and in the ev~porztion of intercepted ~ at~r (~ubter, 1972;<br />
Stewart & Oliver, 1972). Evaporation is likely to be<br />
fastest and hence possibly greater during the warmer<br />
conas. In low-growhg vegetation, t nnspiration and<br />
evaporation are of sirrjlar magnitude but evspara.tion of<br />
interoepted water fr~m for< st is gruater than transpimtiion<br />
loss (~ufter, 19681, up to five tines greater under windy<br />
conditions because af the aercdynar;jc roughness of the tree<br />
oanopy (Ruttar, 1972).<br />
In watershed studies at Cmeeta, USA (~oover, 19441,<br />
clearfelling of mixed hardwoods increased run-off<br />
by nearly 53% wid m-off as a p ercentage of incident<br />
rainfall from to 59$ (c. 41 -6% according to ITi3bert,<br />
1967). D~ta from ot ht r sites sunnariaed by Hibbert (1967)<br />
indicate incmases in run-of"E of the same mJer or less<br />
seer clea~felling forest. At Coweta, eetablisbnt<br />
and growth of pines for 36-1 7 years on two catchments<br />
reduced streamflow to 2 6 below the value expected for a<br />
hrdwood st snd {Swank & Dqlasa, .1974),<br />
fieparation of an area for planting of trees ort~n involves<br />
drainage operations. Fron studies by Pafntor ot al., (1974)<br />
on catchaents with variable soils (peaty pdzols, pe&t,<br />
boulder clay, sand) on Plynljmon in riel~s and at Cmlburn<br />
in north-west England the se operations can led to a<br />
1000-fold incr~ase in los~<br />
of particulate matter and<br />
presumbly also in nutrients. A similar b& sndler<br />
ef'fect occurs mhen an are:. is clearfelled (~omlan et .al.,<br />
19&; Likens et al., 19?0), although Packer (q 967)<br />
conoludes that clearfelling itself is virt-
. .<br />
harmless and it is the subsequent logging operations<br />
~ i c h increase sail erosion and strer:n turbidity (~rness,<br />
1967; Packer, 1967). Likens et al., (1970) studied<br />
effects of clear-felling an am. of a e d har&mods ~12th<br />
sms pine and fir in north-east USA. Their eqerimental<br />
area had a continental type of climate but in sane respeots<br />
resembled parts of tho Lake District . Altitude ranged<br />
f'rm 229-1 006 m, rainfiill was about ? 23 cm cnd the soil<br />
was acid podzolic glacial till overlying acid metafnarphic<br />
rock. The =in results wem as follows :<br />
I , hual run-off of wzter increased by 39% in the first yea<br />
and 2% in the second year afiw clearfelling over the<br />
values expected if the forest had not been cuk.<br />
Particulate matter in streamv'ratcr incr~zsed from about<br />
25 kg to 100 kg ha-', with an increase in inorganic<br />
particulate matter from about a half t o t hree-quarters<br />
of tho total.<br />
Concentrations of a11 rn j or ions, except ammonium, sulphat e<br />
and bicarbonate, ftl the stremwater increased five months<br />
nrter deforestation, Nitrate shm ed a 41 -fold and 56-fold<br />
horease in the first 2nd second years rcspctively afier<br />
clear-felling.<br />
4. The incroase ii cat ions was explained by a change in the<br />
nitrogen cycle jn the forest system, In the un3isturbd<br />
. .<br />
system, any nitmte produced during decomposition of plant<br />
rewins was conserved by uptake by plerrt s but *en the<br />
vegetation tvss removed, nitrate plus associated cations were<br />
readily washed out of the aoil.<br />
Wdrogen ions replace& the<br />
cations in bErth the deomposhg organic natte~ and on<br />
inorganic material 3.
5. Sulphate in st rean-wat ar decreased bec2use ~f increased<br />
run-off and eliaimtion of sulphate generation within the<br />
syst8D.<br />
6, Sremmaker tenperaturea were higher aftar deforestation<br />
0 0<br />
and varied 3 -4 C diurnally in smer ompamd with virkual<br />
constancy prior to felling.<br />
The mnzgement pr:~ctices used by =ens<br />
ot al. , provention of<br />
regrowth of all vegetation afier clearfelling by use of<br />
herbicide, no cunatruction and use of forest roads and no<br />
removal of felled trees fiorc their site, were very different<br />
frm norm1 forestry opcrat ions in IT, S.A. and ix Europe so<br />
their results are likely to he of limit ad applicability<br />
generally.<br />
Soppor (1 975) has placed then in the cwtexb<br />
of results f'rm numerous other catckment studies in North<br />
America and canaluded that sediment and turbidity problems<br />
can be minindaed by careful siting and const metion of Logging<br />
rwds, stream tenporature changes can be avoiba by leaving<br />
a narrow strip of trees or brush alongside strew: and<br />
nutrient losses following clea~cutting are snaU to negligible<br />
if rapid revegetation of the site occurs, The iqortunce<br />
of a contkuous vegetation cover 2nd its associakd litter layer<br />
in retaining nutrients on a site hsts been stressed by Thorns<br />
Bc G~iga1 (I 976) for evergreen mountain laurel in Tennessee,<br />
Tam et d., (197b) also reviewed the effecta of forest<br />
operations with particular relevance to Europe. They provide<br />
evidenoe that nitrate - 1V increases up to &fold in water fiwn<br />
clear-cut areas parkicularly on the more fertile soils,<br />
Addition of N fertilizers, particulmly armaonim nitrate, can<br />
lead to large tnore&ses in N content of atrear~water and<br />
ground water. The fate of added nitrogen on c1ea.r-felling<br />
is debatable but the scanty available avidence suggests that
the soil. pXua vegetation will be able to retdn moet of it<br />
on site. Sopper (1975) oonoluded that use ofN fertilizers<br />
leads to only temporary increases in the N cmtent of run-off<br />
wtter, Phosphorus and other elements [Ire lost in drainage<br />
water f rm poat lands particularly aft ur fertilization with<br />
soluble phosphates am et al., I 974). The latter zuthors<br />
also express concorn th2t increased fertilizer use could lead to<br />
marked chcnges in soil and wator acidity,<br />
iii) Removal of nutrients in tirabor<br />
m n g the past 80 years or so, and particularly during the<br />
past 20 yecra, numerous dutc have been coUscted on the amounts<br />
of organic mtter and nutrients in the various parts of tmes<br />
of a various species grow5ng under a ~ d range e of site conditions<br />
(@in& on, 1 962; Rede, 1 956; Rodin & Bazilevich, I 967).<br />
Ovjngtonls (1959a, 1959b) study of Scots pine is one example of<br />
this type of work (?able 5). He felled a soriss of sam2le<br />
trees of different ages all growing on virtually the same soil<br />
type and in the sane area and measured the wights and chelnical<br />
composition of their cmp~nent pa*s.<br />
roots, needle fzll and on the soil,<br />
He also gathered data. on<br />
He ws then able to estimte<br />
the rates of accumula.tion of nutrients in different parts of<br />
the tree and in plant remains as v~ell as changes in the soil with<br />
time.<br />
For comparison with the tree aata, we have assembled data on<br />
inputs of nutrients in precipitation (~abla 5). These are<br />
of the same order ns values &ven in Table 3 for Moor House<br />
and published data for othsr pwts of Britain, (~gner&<br />
Eriksson, 1958/.t959; Madgvfick & Ovington 1959).
Of the average mnwl upkke of nutrients over the 55 yaws,<br />
a high percentage passes into the leaves and rlltimatoly<br />
Peturns to the soil surface in dead needles, branohm md<br />
cones. Soae nutrient uptake is mtaimd in the tree crm<br />
and roots (not sho~m inTable 5). Only a sraall percentage,<br />
ofken less than 16, is retahed in the trunks.<br />
Clewly,<br />
avemgc annual nukrtent lossea fion the nystem in tree trunks<br />
alone, vrhich can be regarded as losses from the soil, are very<br />
law a d could be accounted for approximat- by nutrient iJlpurt<br />
in p~cipitation. However, precipitation auppliea only part<br />
ofth6 nutrient input,<br />
Droplets and fine dust prticlsa<br />
(aerosols) originating from dusty roads, sea spray and other<br />
sources a180 contain nutrients and they enter the systerr. even<br />
during dry weather.<br />
The size of this input at Thetford is<br />
unknown but Nhite (1969) estinated annul aerosol inputs<br />
t o a deciduous woodland near Grunge-ove r Sands to be I 2520 kg<br />
100 ha-' Na, 630 kg I00 ha-' K, &20 kg 100 ha-' Ca and 12 kg<br />
103 hav' P, The N input in Table 5 is alro a, minimum value as<br />
ztmospheric N is fixed biologically by micro-organisms in soil<br />
and on leaves or ~s atuospheric ammi-trzpped<br />
in acidic<br />
plant residue s. Ovingt an (1 $2) indicated that M fixat ion<br />
in fore st rmy be ab out two-f our times t h6 amount s of N in<br />
precipitathn qu&ed in Table 5, but Jones et al,, (1974),<br />
basing their calcul~tions on nitrogen fixation masu~nents in<br />
b Douglas fir canopy and soil in the southern Lake District ad<br />
tree data from Ovingtonrs studies in sou'sherm Endand plantation<br />
(summized in Ov%n.&on, 1962), estbated t ota3. N fhati on of<br />
-1<br />
757-4974 kg 400 h 3 yr with 58-E$ of tho fixation occurring<br />
in the tree canopy. Alexander (197b) gives a range of &3500<br />
kg N 100 hi1 yr1 fixed in --<br />
Detula, Plnua and Fcea forest soils<br />
on tundra-type sites in the Northern Bomisphere. Brows et al.,<br />
(1969) recorded up to 4900 kg N 103 ha-' yr' fixed in various<br />
moderately acid fore at soils in kuebeo.
'flcathcring of Ixinelal soil mil rock provides sax nutrients<br />
but relevant data on rates of noztht;xting per unit ama under<br />
ficlc conditions are unavailable.<br />
Wference a betnean inputs<br />
and outputs of nutrients for a site .my be taken only as a rough<br />
guide to wecthring rates because of the coaplexity of eaoh<br />
system, the usu~lly lob; pmcision in wtjaaulls~~ent of system<br />
cqononts a:!the existence of long-tern trends in sone<br />
oompments.<br />
None of the most relevant available input and<br />
output dzta for a.fforested catchments, four quoted in Likens<br />
et al., (1967) and one in Jmes (19?1), include estincltr;.? of dl<br />
possible nutrient inputs and outputs.<br />
Although prduction of coqloto nutrient balance sheets for<br />
forests is difficult, car,sidemtiofi of av&luble data above as<br />
EL whole leads to the conclusion that managed fomst systcns tend to<br />
accumlnte nutrients and do not deplete the soil of nutrients<br />
excessively as swestetl by hmie (1956) who under-rated the<br />
importance of the various nutricnt inputs to the fomst.<br />
Rennie prduced some cseful dnt~<br />
on average nutrient uptakes<br />
by trees nnd parts of tmes over 50 and. -100 ycar3 and we have<br />
wed these on a ndified besis to outimte re~oval a? nutrients<br />
in tree stens during forestry operatiorla (Table 6). Bede<br />
used published data on yield,- nutriont caposition and dIY<br />
weights of trees in European forests as a bcsis for his<br />
calaulz-klons, the data coming fro^ 42 originG1 st~ies<br />
includhg<br />
trees in growtl-1 clcsses I - V on prcdoclinmtly acid s d y<br />
soils and soao base-rich soils,<br />
Data vmre grouped into p,ines<br />
(two species), other conif~rs (the aPec$es) and hardwoods<br />
(ei&t species).<br />
Rennie did not explain fUZy why he<br />
sepamted off pin8 data fror, oth:..r data, but he implied that<br />
this was because loa nutrient denand mas expected for this<br />
group
Our estjm~tes of nutrient removal (Table 6) exclude brush<br />
timber of less thm 7 cm in diameter. If brush tiahor ras<br />
removed frm thc aite, the values given would have to be<br />
inoreased by about 37-5s ((~a), 54-615 (K) and 69-8%<br />
{P).<br />
Figures produced by otbr aubhors for individual nutrients<br />
for othclr sites (~vington, 1962) &en differ nw3erLcally h r n<br />
those given in Tables 5 and G but &l agree in stressing the low<br />
percentage of nutriont u?take removed in timber,<br />
Itennie did<br />
not provide data on N removal so rough estimes of loss jn<br />
trunk tiber wen) obtained *am K or Ca loss and the r
stressed, nutrients are ruuoved fim circulztion for many<br />
years in the woody parts ot' tmes and this hobilization my<br />
have a mjor effect on the nutrient stztus of the site,<br />
Renniet~ (4956) datA for tote.1 uptake exclude nutrients in<br />
foliage and roots of thinninp and in litter buk support; our<br />
statements above.<br />
Ef f emnce s bet wean nutrient cycling in coniferous and deciduous<br />
f omst s include nutrient return in litter.<br />
Litte~fall on a<br />
dry weight bc:sis is -l5-16% gruater in coniferous forests than<br />
isi deciduous forests and mineral oontent of conifer litter is<br />
about 35-36% of that in deciduous litter excluding Fagaceae<br />
ray & Gorh, 1364). ~utrients in conifir litterfall per<br />
unit area, excluding N, are th~refore about 41% OF those for<br />
deciduous $ree~. For sites grmhg cmkfsrs, the advantage<br />
of' law nutrient demand is off set by p Mutt ion of large<br />
quantities of nutrient-poor and slowly decomposing litter<br />
which ~ay affect soil characteristics in undesirable way~(~.at<br />
but which, navertheless, my help to retain nutrients on a site<br />
(Thorns Grigal, 1976). The reverso is true<br />
for many deciduous trees with otkur litters occupying an<br />
internesate position.<br />
Compariam of the effects of ~raeina animls and tmas an the scil<br />
The main differences and similuxitius in tho ecological effects of<br />
grazing and forestry fsll into two main classes, a) effects on the<br />
soil and b) renova1 or loss of nutrients frm the systerrl in aniraals<br />
or timber, in solutf on and as particulate material.<br />
a) Effects on the soil<br />
Soil coqaction an4ior disturbance by anids, &n and vehicles<br />
.v- IOC;E- on path$ and r=ds tath bath EXL far+<br />
*and<br />
foxcstry but this does nat appozr to be a major proBlen
over large areas largely because of the low intensity or<br />
frequency of use and because affected meas tend to recover<br />
naturally (pp, 3 - 8 & 23 - &). Both uses also lead to<br />
changes in vegetation which reflect back on the soil<br />
(pp. 8 - 12 12 19 - 23). Data are not avajl&le which<br />
allow a comparison of chan~s in soils and vegetation for the<br />
two uses in the Lake District.<br />
Evapotranapimtion is higher for foest than for non-forwst<br />
areas (~ouglasa, 1967;<br />
OvFngt on, A 968; Ilutter, I 9681, largely<br />
because of the higher evaporation in forests, trampifition<br />
ten&g<br />
to be the sane b forests and grassland in the Bdtish<br />
climate (~ter, 1968). This leads to a drier soil and lower<br />
run-off for fornuts than for non-forest.<br />
The tree canopy<br />
together with the layer of' plant remains on the soil surface,<br />
help to protect the soil *om<br />
the direct impact of W all and<br />
from climatic extremes thus f avhg root growth and activiS&.<br />
In corrtrad, on grazed non-forest areas, management tends to<br />
reduce the protective influmoo of vegetation and plant refiaba<br />
by encouraghg grazing of tho award and reducing the amount<br />
of p h t ramins on the soil stirface.<br />
Tree roots undoubtedly bind tho soil on slqes better than the<br />
roots of hsrbcgo Species. It is well-bow for. exmple,<br />
that gullying cnn be halted if trees can be planted around<br />
the rin of the gully.<br />
Whether it is necessary to plant trees<br />
h a particular area to prokect the soil against erosive<br />
influences mst ulthately depend on the a&es<br />
of erosion and<br />
soil fomtim under normal climate and the frequency, severity<br />
and erosive influence of olimatic extrenzes. In comercid.<br />
foreats, the times of planting and tuber extraction are Uely<br />
to be the crikical periods f o soil ~ erosim whereas on a grazed<br />
ares erosion potential changes gradually reaching a critical<br />
point only when hi&<br />
qotbntial coincides with extreme o-te.
)4<br />
In gener:r1, t!€e roots extond- to d. greator soil depth<br />
tbs.n ao rcots of herbagc species (Douglass, 1967; tutter, 1968).<br />
fhis iryfies that Bore Eator ana nutriedts are potentLo.lly<br />
aveilcblc to trces than to herba6e spccier. In 3Jdition,<br />
trees alpoer to be ablc to orploit nutrior* s in the<br />
under]J.ing rock by ct vely etroo-r-6ing physical blcak up<br />
aril cheidca]- weathexing jn the rootin8 zone ( ?p. 19 - ?9).<br />
erazed upland pd3tur"cs, unLikc forest<br />
accurulate a l-arge store of nutrients<br />
systens, do not<br />
in the stanaing vogetation<br />
so their nutli.ent cycl-ing tonals to be faster than that in<br />
woodlands, palticularry where aost of thei! pri!',ary prcductioo<br />
is d.iverted into thc grizing criDa I ( pp. B - 1Z).<br />
Both<br />
for€sts ana Brassf.anas retuE) Iargs qua.btit:es of org&rlic natter<br />
and nutriontr to the soil su!f.!ce :j.rrnu€ll-Jr and tlds return<br />
tends to coLmteract th( leuching Lffect<br />
of high rainfrll<br />
larticulail-y in forests where nutrients t6nd. tc be brou8ht up fron<br />
ihe deope r soil- or rock. Data given jlr lray & cor*ra$ (1964)<br />
s.rld. Rodin & Bazilevich<br />
(1967) togethe! suggest that ailowtd<br />
of Litter-faL1 n@y be silrj.lar for both lanrl-uses in & given<br />
clillatic zobo. The rates of decoi0positlon of J.eafy pLolt<br />
l€Eains anC of releaso of tho containeal nutrients<br />
appecr to be<br />
high]-Jr rarlabl€ b1l6 of the salre ordor in forest and Erqssl.lnal<br />
(Laiter & Cft\gi, 1967t l,ii,koLa, ,195{). Lj-Edn6, fortilizer.<br />
adalitions a$d. incr€asetl stockirlg orr hil,l<br />
pastur€s encoulsge<br />
fast€r nutrient cycling r*lelEas the very slow alecoryosltion of<br />
woodJr&"lerial iI1 foresis tends to r€ aral cycli-n€.<br />
Both hil]-farrdng and. forestry can proiluoo changes ijl tho soi-1,<br />
srrch as decruases i.11 the o!€ianic aatter o! nutrieBt cort 6nt<br />
and irl availab],e nutricnts, w]rich nay be i-nter?teted as<br />
aeterioratio!.<br />
Ho1,lever, utleBs these changes lead to lates of<br />
erosion gree.ter than the rate of soil<br />
$ecessarily<br />
of !l3-j or ix+ort.nnce.<br />
for:Ft ion they arc nob
) Removal or loss of nutrients from the systom in animals or<br />
timber, in solution and as particulate matefial<br />
From Tnble 6, sheep production involves far less renoval<br />
of nutrients from the hill than forzstry, even for N which<br />
is muck more abundcmt in animal tissues than in plant<br />
matorial,<br />
Data given by King & Nicholean (*19&) for Ca<br />
and P removal in pines (af'ter Rennie, -1 956) and in a sheep<br />
crop (their o m estimates, p, 14 above) supports this<br />
0 onolusf on. The same c onclusi an would be reached from<br />
our estimates, even if the stocking density ma increased<br />
to 10 ha' , which mi&% be found under very intensive<br />
farming or on small favoured grazing areas with muck lower<br />
ovorall st ocking densities .<br />
Any major disturbance to both systems such as plougEng,<br />
burning, road-making, fertilizing, tends to result in a change<br />
in loss of soil or nutrients in the-run-off Water. This<br />
change is particularly marked during site preparation and at<br />
felling the in forestn (pp, 24.-281, an sspect which may<br />
exaggerate the difference in nutrient loss/removal between<br />
forests and grazed areas,<br />
Vie oonolude from the evidence assembles above that the<br />
vegetation, and to some e ~sn the soil characteristics<br />
of an upland area, may be changed to meet the requirements<br />
of s chosen land-use, but any change must be mde smoothly<br />
and a continuous vegetation cover must be maintained as<br />
'far as possible to avdd soil and nutrient Loss.
Some evidence suggests that natural inputs to the f o ~ s t<br />
are greater than those to the gmzod system (Davies, 1969;<br />
Mindernan & Leeflang, 1 968) but outputs, other than the<br />
crop,iire si.nilar for both land-uses (pp. 12 - 15 & 23 - 32,<br />
. . Roberts & Jams, 1972) the ecosystems are undisturbed.<br />
This is reflected in the greater accmuktion of nutrients<br />
in the f omst than in the ~ r~zed system (pp. 28 - 32).<br />
1% gratefully ecknavdedp the advice md informtian madily given by<br />
Dr. 'dl. 0. Binns of the Foroskry Comrdssion, Dr. M. J, noate of the<br />
IUll Farming hsearch Organization and cur oalleagues in the Institute<br />
of 'Terrzstfial Ecolw in particular, Dr. D. P. Ball, hks. c. Cumins,<br />
Mr. A, 3. P. Gore, Dr. 0. W, Heal, Professor F. T. Last, X%ss P. M.<br />
Latter, Dr. J. E, Satchell, and Mr. D, iklch,
pendix: The effects of land use and manawntent on upland ecosystems,<br />
with particular reference to soils in the Lake District,<br />
Merle~vod Research and Development Paper No. 68.<br />
K. L. Bocock and J. K. Adamson<br />
Swnmam- and conclusiana<br />
These notes, based an a paper by Bocock and Adamson, summarise the<br />
main effects of land-use and management on upland ecosyste~s in the<br />
Lake District, with particular referunoe to soils.<br />
Most of the<br />
relevant data used were oollscted out side the Lake District . Unless<br />
we have indicated reserv~tions about the applicability of bta to<br />
Iake District conditi.4, the reader may assume that we have considered<br />
and accepted its zpplicability.<br />
Particular enphasis is placed on the effects of hill-farming, forestry<br />
and recreation. Any or all of these may occG on a water catand<br />
the lakter use has few special features, so it will be covered<br />
in discussion of the other uses.<br />
1<br />
The altitudinal zone, which is of partioular interest here, lies<br />
between the intensively managed coantul plain$ ' and valley b ott oms<br />
with deep, predominantly fertile soils and the viTtu8ll.y soil-less<br />
and unmanageable high mountain t opa, Soils range from well-drainedJ<br />
b rovm earths carrying &ras tis-Feat ucn grassland, frequently invaded<br />
by Reridium, on the lower fells, to nutrient-poor, often peaty, but well-<br />
-<br />
drened soils with Calluna and vaccinium, or poorly. aerzted gleys with<br />
Nardus grassland,on the higher gentlo slopes.<br />
Stagnant, or nun-<br />
stagnant bogs, dominated respectively by Eriophcrum and MoUia, occur<br />
on level arezs at most altitudes in the zone of interest,<br />
The &in effects of the grazing animal include treading of the soil<br />
and vegetation, defoliation of' the vegetation, and removal of nutrients<br />
from the ecological system in the animal crop,
The effect of tre-g varies with age, size, and. breed of animal<br />
involved, more specifically with hoof area, the pressure exerked<br />
on each hoof, the nursber of times, and the viay in which the hoof<br />
is applied to the ground per unit area and per unit time, and the pattarn<br />
of moveaent of the &Lima1 within an wea.<br />
The fm data available for hill breeds and conditions and -extra-<br />
polation from data for lowlands, indicate that cattle tmad twefour<br />
thos more he-lviu than sheep, and their stride ad<br />
am;& are respectively three and four times @eater.<br />
truvel about the same distance per day, around 2-5 km.<br />
hoof contact<br />
Sheep and cattle<br />
Such data<br />
suggest that, with the level. of stocking camonly found in MU1 mas,<br />
0.2-1.0 sheep ha-' or 0.2 cattle ha', -h of the pasture is tmmpled<br />
several times per year, Because of vegetation variation, food<br />
selection, and tho chara.cteristil?s of diurnal and sensorial movement<br />
of animis, trampling is ooncentrated on areas of more patdtable<br />
vegetation, 9.g.<br />
w-Festuca, or on muoh-used paths.<br />
Trampling muse soil ompaction and aisturbance and damage to the<br />
vegotztion but may also be beneficial by areatkg new sites for<br />
ea%ablishment of seedlings, by f idng seeda h the soil and by<br />
prom&%<br />
tillering.<br />
Soil oornpaction is conoentrated in the top few cms., of soil and i s<br />
gmatesh, on soils rich in clay, organic matter and moisture and lea&,<br />
on the aell-dra5nad sandy and stony soils, It brdsto changes in<br />
soil characteristics such as aeration, root pene$rabiEty, infiltrp tian<br />
rate, and thermal ~h~ractexistics, all of Mch cm affect soil<br />
- fertility and vegetation composition or performance.<br />
rn<br />
Small agficultural vehicles exert;' similar pressures to those oaloulated<br />
for animnls and their passage has simil-r ef i'ect s to those of animal<br />
tmmpling, but is concentr~ted more on established tmcka,
Soil coqaction does not appear to be a mjor proLlem in graeed<br />
hill and upland areas bec~use of low at mldng rates, infrequent<br />
use of agricu1tur:~l vehicles, recovery of conpacted so51 under the<br />
influence of the frequent mhter frosts and, in the aase of animals,<br />
by the swamping of trampling effects by the beneficial effects of dung<br />
and urine depositf on.<br />
Soil disturbance occurs on much-used tracks, particularly on soils<br />
rich in clay, organic mtter and moisture, on steep slopes where<br />
animls -bend to slip a d slide and for cattie rather than for the<br />
lighterst spping sheep. Any disturbed soil is suscefli ble to erosion<br />
aa can be seen on hill paths in wet weather, Hollows cPeaked on<br />
hill-aaes by sheep action are focal points for sheet ereaim.<br />
However, the extent to which the varying rates of erosion in the<br />
Lake Rstrict in the past and present can be attrihted to the<br />
effect' of aiimls is unclear,<br />
TraqLin~ and defoliation by grazing may result lt ditmge to, and hence<br />
in redwed produot ion by, plants,<br />
Ao plants differ in their sensi.blvi*<br />
to cLam?,ke and t o changed sail conditions resulting from trampling,<br />
grczing animals can elloourage changes in the vegetation composition vrhich<br />
my lead ultimately to soil changes associated with changes in the type<br />
and anount of ~ 1~n-k ramins redcbing the auil surface.<br />
On hill-land ungrazed by domest icuked atlimals , plant materia.1 eva&uaf ly<br />
dies and f oms prt of the, surfwe mat of plant remiins.<br />
The type of<br />
decomposition which this mt undergoes under the influence of the high<br />
rainfp-U and lon temperatures of upland areas, encoureges high acidity<br />
and 20wnutrrient availzbility in the upper soil,<br />
Gracing charnels<br />
an increased proportion of the herbage through the animal and so reduoea<br />
the supply to the'mt.<br />
The effeots of a reduced mt and of deposited<br />
dung and urino change the chemical characttfistics of the upper soil,<br />
increasing nutrient availability and turmover.<br />
Thi a, together with<br />
select iva f eedjllg by animls~ particularly by sheep, encourages changes<br />
in the vegetation,
Assessment of the importance of the various practices. and factors<br />
associt~ted with gr zing and which ixlf lucnco veget:iti.on<br />
and ultimately<br />
the soil ht~s not been carried out in the Lake Xntrict, but eviddnce<br />
from other upland rtre~ts suggssk thht intensity, tiaing, and 1oc::tion<br />
of grazing nrld use of fertilizers and herbicides are of prime impfiance.<br />
A complete assessment of the importance of removal of nutfient s in the<br />
aim1 crop cannot be mhuo for the Lake District: because of l ~ck of data<br />
on inputs of ni-trogen from variouv types of fixation, inputs of dl1<br />
nutrients in asroxols and froan rock weathering, and outputs of all nlrtrjeats<br />
in run-off.<br />
However, available data, ooupled with data from other<br />
sreas, suggests that removal in mirmls is likd~ to bo very anall<br />
in mlbtion to the total nutrient reserve in the eoil and to input<br />
in precipitation,<br />
Fhosphorus input in procipitatim and output in<br />
bmls are appraximteb equal, so, for this element, remural in<br />
animals may lead to an overall loss frm the system mhen all inputs<br />
and outputs a1.e aooounted for.<br />
Trampling of soil and vegetation is the main effect on soil associated<br />
dth recreation.<br />
Detailed cF,.znges are lik~ly to be s ~ l a to r those<br />
caused by animal trarrrpling, although few data have beon oollected in<br />
the Lake District, and data are not available gonemlly which a11mf<br />
detailed comparisons of the effeats of trampling by Man and by animls,<br />
;. Trampling aamage ia not considt,red t o be a EEL jor problem except on<br />
well-used footpaths, particul2rly an steep slopes, on v:&<br />
amas, and on tha higher altitude ridges,<br />
pe~ty<br />
Use of vehicles on<br />
unsurfaced tracks znd paths has similar effects to those produced<br />
by Mani s trampling end, currently, rarely produc~s significant d-e<br />
in the Lake Distdct.<br />
The win effeots of treos and forestry m the soil include those<br />
associated viith tme mots, plant remains, soil disturbance during<br />
forestry operations, influences on run-off iiatcr quality and, rcnovd.<br />
of nutrients from the system in timber.
Tho soil b'cabilizing effect of tree roots is of particular importanoe<br />
on steep slopes. The zone of soil around tree roots is a site of<br />
active miners1 eathe he ring. The importace of the latter effect far<br />
forest in t:w 1,a.k~ District is unclear. The presence of root channels<br />
in aoil rer,dt.rs the latter more permeable to ~vatcx, wh:,reas rod<br />
decomposition adds humus and rat rients slowly throughout the soil profile,<br />
Plant renains on the soil surf~ce buffer the soil against the effects<br />
of clim'ie, part,icul&rly direct insolation and extremes of air temperature<br />
and rainfall,<br />
The rats and type of deompmftion of plant remains<br />
influences tho chemical and physical properties of the underlying soil,<br />
Conifer litter, like _Ca_lLun.n and Erica on moorland, has the rep*tian<br />
of causing physical, chemical and biological deterioration of soil,<br />
'%ilst these effects mmzia sonewhat controversial, and incomplete3y<br />
understoca it is clr;a,r that they vary with soil type, site characteristics<br />
and tree species.<br />
Flelevan'c locsl data a= fen arid indicate tendencies<br />
towards acidity, low n~trierrt cvczilability and podzolization in many<br />
upland soils but no clearly developed podzol profiles.<br />
Evidence from<br />
elset~here indicates that trees, even conifers, will grow well on<br />
aimilur soils to thona f3md in the Lake District without causing<br />
serious aoil degr~cation, although they m y cause the tendencie s<br />
indio~ted 2bove.<br />
The maJdmum dj-rcct eflcct of forerrtry operations on the soil occurs<br />
during site preparation cnd haroastir~g, both of tvbich involve use of<br />
heavy machinery ~:hich coqacts and disturbs soil, partly because of<br />
its om weight, and partly because of its use in ploughing, drt;bing<br />
or logging.<br />
Excegt for light cross-country vehicles and heavy trucks,<br />
such as timber lorries which can exert pmssurt2s ori the soil of up to<br />
-2<br />
about 8 kg ~ rn-~, vehicle pnssurus fall in the range 0.2-4.6 kg om ,<br />
aboat the sme as t h static ~ pressures exerted by anim~ls. One<br />
-2<br />
application of about 0.2 kg cn! can reduce soil pore space by<br />
and 1&2@<br />
of an area can be affected by vehicl~ a during tractor losing.<br />
Data from other aro:ta suggest a that soil cornp~ction by forestry is not<br />
a major problem, but that mrked vegeti-tion changes occur after ploughing,<br />
draining and ro~~liing. Theso chkng~s xi11 ultdtely reflect back<br />
on the soil.
Fo=sts have an appreciable influenoe an the hydrology of a site,<br />
including soil moisture st:it us md run- off. Frm spirtj.tion mtes in<br />
forest and grasslarid are of approximately the sa2.e ardor but forest3<br />
intercept up to half, but more commonly around 2@40;6 of precipilation,<br />
of'ten several tines the interception for grassland, Intercepted water<br />
is evaporated so the soil tends to be drier and less let~ched under<br />
forest than under dense grzssland.<br />
Site preparation leads to a 103s of particulate matter and nutrients in<br />
run-off, which may continue for several years after planting of the<br />
fo~st. Rcdnaking also incmases soil en& nutrient loss frcm the site<br />
temporarily.<br />
Felling, o specially clear-f elling, leads to hcreuse s in a Oi1 leachf ng,<br />
in run-off,<br />
run-off.<br />
and in the amounts of particulate mtsr5al and nutrients in<br />
Soil and nutrient loss is only slight if loming is<br />
carried out carefully, a h d if rapid regrowth of herbaceous vegetation<br />
occurs.<br />
Feliiiing lezds to increases of several OC in mean soil and<br />
at ream temperature and in the diurnal temperature mn ge.<br />
Tehperatul-e<br />
ohanges will have an appreciable effect on the numbers and activities<br />
of fauna, flora and microflora of these habitats.<br />
Fertilizers and herbicides used in fomstry, affect the quality of the<br />
run-off water only slightly and temporarily, if they are applied<br />
carefully. However, theywill have aom effect on the soil by<br />
altoring biolo&ic*.l zctiviky or the type and amount of plant remains<br />
reackdng the soil surfme.<br />
Forest systems, in contrast with non-forest systems, accumulate a large<br />
nutrient capital in the trees themsulves and in the plant remains on,<br />
and in, the soil, Factors which favour,this build up include evergreen<br />
oor~dition of mny forest trees, resistance to decmpoaition of litter,<br />
exploitation of n greater soil volume by tme root3 than by roots of<br />
pssland and moorland plmt s , except pe rfiapa Yteridium, greater t rapphg<br />
of aerosols &d possibly greater minerel weathering under fo~st than<br />
under non-f ore st.
Wy a few gpercenk of the nutrient uptake of trees, often less than 1C$,<br />
is retained in the trunk, and this is approximtely the same as nutrient<br />
amountc in preaipitation,<br />
to 4 ~ 9 of ~ those 2 in trunks of 1;he min trees.<br />
Brush timber contains nutrients equivalent<br />
Timbt-1~ extraction<br />
therefore removes only a smil fraction of the annual nutrient kcom<br />
to a site, but, nevertheless, removes muck nore - for some nutrient:<br />
mom than ten times more - than that removed h the minal crop,<br />
To summarize the above, the ckzractefistics of soils under different<br />
land uses and rnanagernerrts often differ mrkedly as a result of the use<br />
or mnagemnt.<br />
ahen use and ~nagement are altered, soil changes occur<br />
as natural adjustmeats of the ecosystem t o the factors applied.<br />
These<br />
changes rarely load to severe deterioration in soil quality, or to soil<br />
erosion, unless changes hax been made suddenly and without ca,wf'ul<br />
planning.
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fa!16 J. Part of the nutriont bueget for the BJ ha Rough Sile<br />
catchnent at Moor House, rood.ified afte! Criep (1%6).<br />
(kg 1@he year ' ).<br />
Na<br />
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N<br />
Prc^i -i +r+; ^h<br />
SoiL reservo 1<br />
510@<br />
3a7<br />
175t60<br />
896<br />
i79240<br />
57<br />
81500<br />
820<br />
50160<br />
Stl.eao uate!<br />
452L<br />
Feat erosj-ob 28<br />
Strean fauna O.14<br />
896<br />
M<br />
o'47<br />
5375<br />
48'<br />
o.09<br />
40<br />
o.5t<br />
294<br />
1\53<br />
5,58<br />
sh€6p (o.22 ha-1) 0.19<br />
1 .90<br />
1.18<br />
5.Jo<br />
lotal output 4552<br />
1'to5<br />
585o<br />
87<br />
1768<br />
'* EstiEeted frcn Crispts peat nutfient content de,ta anal an averts'gq<br />
peat depth of 1.5 n (Xaryeea weIch, 1969).
TabLe 4 Input of nutrierlts in lrocipitotion aod output of<br />
[utrie]tts in sbeep al14 $'ool_ in the Lak€ listrict<br />
on the lrbole Moor Houso N.N.R. (kg .1OO ha-1yr-1)<br />
a_lld.<br />
Ir€.ke Dj,strict<br />
precipitatioJ lgc-{/t+a f,o-1,rD 23-1@ 577-15@<br />
sheep2 1J.B 27.8 8.1| 57.9<br />
]r!o,9l liouse<br />
heeipftationf to: A96 57 82o<br />
Sheep[ f.1 23.a i.2 49.o<br />
1. Range of arailabl-e alata, after At]en €t al- (1968), Sutcljffe &<br />
cal:rick (1911), Iltdts (1969), lrldte et al (19/).<br />
2. After feffes (1966). Stookin8 dobsity 2.5 ha'1 .<br />
J. nrter Criep (1966).<br />
)r. .Af'ter Rawes & Welch (1969). SbockiDg d.onsity 2.2 ha'1 .
Table 5 hrt of the nutrj-ent bud.got for a plarrtation of Sryear<br />
old Soots pin6 at Thetfotd (t.g too t1t-ly"-1 ;.<br />
NaKCAPN<br />
Precipitationl 197c,51@ 19G540 65c',-12cn 21-1tx) 577-15|J.._<br />
Uptake by trees2 40 t51r+ t+13o 751' BnB<br />
riltter fa112 78 2556 4i52 5'14 6J62<br />
tross i.rl stelra<br />
(ttt:ur:.rlgs up<br />
to 55 years) 9 a78 J82 4 292<br />
loss i,n steraa<br />
(tfri:rnirgs up<br />
to 55 years alra<br />
cle.-r<br />
fe116d- stglca<br />
at 55 ycars) 18 2 6oL 58 45t<br />
l. lan8e of availallo data for the lake Dtstrict, of'ter AJLen et al-<br />
(t950), sutc:-irre & carrj.ok (19U ), nhite (1969) "rd'<br />
ltrhite st al<br />
. (1e71).<br />
2, .t'f]a Ovturgton (1959a, 195%).
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ISFXRE}, CL S<br />
Alsxaniler, V. (197f).<br />
A sJ.nthesis of the I3P Tundra Sio[[e<br />
circulqro1&r stud.y of ldtrog6n fixation.<br />
aJ]al Deconposition i-a lundra.<br />
In Sol-1 orAat]-isns<br />
(Holding, A. J., Hea]., 0. I;,<br />
Ma-c1o6n, S, f, Jr., & Flanagan, P. rl., Ed.s.), 10!-121 .<br />
5t oci.iol,n:<br />
lundra Bionc Steering Cooxrittee.<br />
./[1€n, S. !., Car1is16, A.<br />
. content of r€,inwater.<br />
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