Influence of Burning Practice in Shifting Cultivation under Different ...
Influence of Burning Practice in Shifting Cultivation under Different ...
Influence of Burning Practice in Shifting Cultivation under Different ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics403<strong>Influence</strong> <strong>of</strong> <strong>Burn<strong>in</strong>g</strong> <strong>Practice</strong> <strong>in</strong> Shift<strong>in</strong>g <strong>Cultivation</strong> <strong>under</strong><strong>Different</strong> Climates on Nutrient DynamicsSota TANAKA*Graduate School <strong>of</strong> Kuroshio Science, Kochi University, B200 Monobe, Nankoku 783-8502, JapanKeywords: Japan, nutrient dynamics, shift<strong>in</strong>g cultivation, Sarawak, ThailandAbstractThis paper presents a comparison between the traditional shift<strong>in</strong>g cultivation systems that have been reported<strong>in</strong> previous studies. The aim is to exam<strong>in</strong>e the <strong>in</strong>fluence <strong>of</strong> different burn<strong>in</strong>g practices on soil nutrient dynamics <strong>under</strong>temperate (Japan), tropical monsoon (northern Thailand) and tropical ra<strong>in</strong> forest (the Malaysian state <strong>of</strong> Sarawak, Borneo)climates. The system <strong>in</strong> Japan <strong>in</strong>cludes cereal cropp<strong>in</strong>g cont<strong>in</strong>uously for three to four years. The amount <strong>of</strong> fuel (plantmaterial to be burned) is estimated to be 50 t ha -1 at most. Ignition is started from an upper slope, and the land is burnedslowly and carefully downward. The system used by the Karen people <strong>of</strong> Thailand consists <strong>of</strong> a s<strong>in</strong>gle year cropp<strong>in</strong>g <strong>of</strong> ricefollowed by 10–15 years <strong>of</strong> fallow. <strong>Burn<strong>in</strong>g</strong> is carried out at the end <strong>of</strong> the dry season and a fire is ignited at a lower slope. Thesystem <strong>in</strong> Sarawak is similar to that employed <strong>in</strong> Thailand. In each <strong>of</strong> these two regions, the amount <strong>of</strong> fuel is around 100 tha -1 after 15 years <strong>of</strong> fallow. The <strong>in</strong>creases <strong>in</strong> soil temperature from burn<strong>in</strong>g are <strong>in</strong> the order Thailand > Japan > Sarawak,where the differences can be attributed to soil moisture content and the direction <strong>of</strong> fire ignition. The effect <strong>of</strong> soil burn<strong>in</strong>g isthus more obvious <strong>in</strong> Thailand and Japan than <strong>in</strong> Sarawak. After three to four months <strong>of</strong> burn<strong>in</strong>g, the soil m<strong>in</strong>eral N content<strong>in</strong> many regions decreases to the <strong>in</strong>itial pre-burn<strong>in</strong>g level. A comparison between the level <strong>of</strong> nutrients <strong>in</strong> ashes and soilssuggests that the addition <strong>of</strong> ash plays an important role <strong>in</strong> elevat<strong>in</strong>g nutrient levels <strong>in</strong> Japan and Sarawak. However, this maynot be the case <strong>in</strong> Thailand. The <strong>in</strong>creased nutrients return to their <strong>in</strong>itial levels with<strong>in</strong> one year <strong>in</strong> Sarawak and Thailandand after three or four years <strong>in</strong> Japan, which could be due to differences <strong>in</strong> the nutrient-hold<strong>in</strong>g abilities <strong>of</strong> the soils as wellas to climatic <strong>in</strong>fluences. These differences <strong>in</strong> soil nutrient dynamics are considered to be reflected by the different cropp<strong>in</strong>gsystems used <strong>in</strong> the regions.1. IntroductionShift<strong>in</strong>g cultivation systems are agricultural methodsthat require low <strong>in</strong>put. Such methods are still commonlyconducted <strong>in</strong> tropical regions; however, <strong>in</strong> the past,they were also widely practiced <strong>in</strong> temperate regions.Traditional shift<strong>in</strong>g cultivation systems practiced by<strong>in</strong>digenous farmers are generally believed to be welladaptedto the climate and environment conditions <strong>of</strong>particular regions, and therefore to be well-balancedand ecologically sound. Intensified systems, with anextended cropp<strong>in</strong>g period and a shortened fallow period,can cause land degradation, such as nutrient depletion anderosion. Irrespective <strong>of</strong> whether a system is traditional or<strong>in</strong>tensified, the role <strong>of</strong> burn<strong>in</strong>g practices is considered tobe positive <strong>in</strong> terms <strong>of</strong> land preparation, weed and pestcontrols, and <strong>in</strong>creased soil fertility. Although numerousstudies have been conducted on burn<strong>in</strong>g practices fromthe viewpo<strong>in</strong>t <strong>of</strong> soil science, most <strong>of</strong> them have focusedon changes <strong>in</strong> soil nutrient levels caused by burn<strong>in</strong>g andcrop production with<strong>in</strong> one field or one region. In contrast,several comprehensive <strong>in</strong>vestigations have reviewed*Correspond<strong>in</strong>g author: Sota Tanaka, E-mail: sotatnk@kochi-u.ac.jp, Tel: +81-88-864-5183, Fax: +81-88-864-5183Received 22 August 2011; accepted 22 December 2011
404S. Tanaka / Pedologist (2012) 403-414previous studies <strong>of</strong> tropical and subtropical regions, andhave evaluated the <strong>in</strong>fluence <strong>of</strong> burn<strong>in</strong>g practices on soils(Giard<strong>in</strong>a et al., 2000). Because the ma<strong>in</strong> purpose <strong>of</strong> suchresearch is to construct a model <strong>of</strong> the nutrient dynamics<strong>in</strong> shift<strong>in</strong>g cultivation ecosystems, data are compiled foranalysis from a variety <strong>of</strong> regions.However, assum<strong>in</strong>g that a shift<strong>in</strong>g cultivation systemis <strong>in</strong>deed well-adapted to the climatic and environmentalconditions <strong>of</strong> a given region, the significance and extent<strong>of</strong> the <strong>in</strong>fluence <strong>of</strong> burn<strong>in</strong>g practices on soil nutrientdynamics should change <strong>under</strong> different shift<strong>in</strong>g cultivationsystems and climates. To <strong>in</strong>vestigate this hypothesis, thepresent paper exam<strong>in</strong>es and compares the <strong>in</strong>fluence <strong>of</strong>burn<strong>in</strong>g practices <strong>under</strong> temperate, tropical monsoon andtropical ra<strong>in</strong> forest climates, based ma<strong>in</strong>ly on reporteddata from Japan, northern Thailand and Sarawak <strong>in</strong>Borneo, respectively. However, <strong>in</strong> Japan, quantitative datarelated to nutrient dynamics <strong>under</strong> shift<strong>in</strong>g cultivation arescarce because, except for a few isolated cases, shift<strong>in</strong>gcultivation stopped be<strong>in</strong>g practiced <strong>in</strong> 1950s or 1960s.2. Characteristics <strong>of</strong> shift<strong>in</strong>g cultivation systemsThe characteristics <strong>of</strong> traditional shift<strong>in</strong>g cultivationsystems <strong>in</strong> several Asian countries are compared <strong>in</strong> Table 1.In Japan, burn<strong>in</strong>g <strong>in</strong> a traditional shift<strong>in</strong>g cultivationsystem had three tim<strong>in</strong>gs for burn<strong>in</strong>g, spr<strong>in</strong>g, summer, andautumn (Tachibana, 1995). A fire was ignited at an upperslope, which then slowly moved downward. Unburned orcharred fuels were subsequently piled up together andreburned. Many different phrases were used to expressthis burn<strong>in</strong>g method (Sasaki, 1972), for example, “honemade yaku” (burn to the core (hone = bone)) and “sokomade yaku” (burn down to the bottom).Among the groups practic<strong>in</strong>g shift<strong>in</strong>g cultivation<strong>in</strong> northern Thailand and Myanmar, the Karen and Lua’people practiced shift<strong>in</strong>g cultivation with short cropp<strong>in</strong>gand long fallow periods (Kunstadter, 1978). The time forslash<strong>in</strong>g and cutt<strong>in</strong>g was traditionally January to Februaryand that for burn<strong>in</strong>g was March to April (the end <strong>of</strong> dryseason). In Borneo, many tribes conducted shift<strong>in</strong>gcultivation, but the practices were similar to each other,with slash<strong>in</strong>g and cutt<strong>in</strong>g done <strong>in</strong> June and July and burn<strong>in</strong>gdone <strong>in</strong> August and September. In terms <strong>of</strong> the location<strong>of</strong> fire ignition, the area between Yunnan and Thailandseems to have formed a boundary; to the south <strong>of</strong> thisboundary, the <strong>in</strong>itial burn<strong>in</strong>g position was generally on alower slope. The author has observed that the Iban people<strong>in</strong> Sarawak always started burn<strong>in</strong>g from the lower part <strong>of</strong>a slope, even for young fallow forests <strong>of</strong> less than 5 yearsTable 1. Characteristics <strong>of</strong> traditional shift<strong>in</strong>g cultivation systems throughout Asia.Region Tribe Ignition from Cropp<strong>in</strong>gperiodCropReferenceJapan upper 3–4 y cereals Sasaki (1972)upper 3–4 y cereals, oriental paper bush + paper mulberryupper 1–2 y turnip + forest plantationYunnan upper 1–5 y rice, cereals Y<strong>in</strong> (2000)Thailand Lua’ upper 1 y rice Kunstadter (1978)Karen lower 1 y ricePhilipp<strong>in</strong>es Hanunóo upper (secondary forest)lower (primary forest)1 y rice Conkl<strong>in</strong> (1957)Borneo Iban lower 1 y rice Freeman (1970)Kantu’ w<strong>in</strong>dward 1 y rice Dove (1981)Kenyah lower 1 y rice Ch<strong>in</strong> (1985)Cereals <strong>in</strong> Japan are typically:(1st and 2nd years) Japanese barnyard millet (Ech<strong>in</strong>ochloa esculenta, hie), foxtail millet (Setaria italica, awa), and buckwheat (Fagopyrumesculentum, soba)(3rd and 4th years) soybean (Glyc<strong>in</strong>e max, daidzu), and adzuki (Vigna angularis, adzuki)
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics405old. Reburn<strong>in</strong>g was common <strong>in</strong> all regions. Fire ignitedfrom lower slopes moved rapidly upward <strong>in</strong> comparisonwith ignition from an upper slope.The length <strong>of</strong> cropp<strong>in</strong>g periods was also regiondependent. In the temperate regions, the cropp<strong>in</strong>g periodextended up to four or five years, whereas <strong>in</strong> the tropicalmonsoon and tropical ra<strong>in</strong> forest regions, a s<strong>in</strong>gle year<strong>of</strong> cropp<strong>in</strong>g was common. In Japan, cereals were usuallyplanted. Among them, Japanese barnyard millet, foxtailmillet and buckwheat were planted <strong>in</strong> the first and secondyears and beans (soy and azuki) were planted <strong>in</strong> the thirdand fourth years. In northern Thailand and Borneo, theprimary crop was upland rice.3. Amount <strong>of</strong> aboveground biomass to be burnedSugawara and S<strong>in</strong>do (1985) experimentally estimatedthat the actual amount <strong>of</strong> aboveground biomass slashedand cut to be burned (fuel) was 26.7 t ha -1 for vegetation<strong>in</strong> Iwate Prefecture <strong>in</strong> Japan that had la<strong>in</strong> fallow for 10years and was dom<strong>in</strong>ated by Quercus serrata (Table 2).In contrast, Takahasi (1947) reported fuels amounts <strong>of</strong>18.5 t ha -1 and 16.6 t ha -1 <strong>in</strong> his experiment <strong>in</strong> YamagataPrefecture. Although the length <strong>of</strong> the fallow periodswere not described <strong>in</strong> his paper, these are considered tobe around 7–8 years or longer judg<strong>in</strong>g from the context.For slash<strong>in</strong>g and burn<strong>in</strong>g agriculture accompanied bytimber harvest<strong>in</strong>g or forest plantation (Yakihata-zor<strong>in</strong>),fuels were ma<strong>in</strong>ly composed <strong>of</strong> the branches and leavesleft after timber harvest<strong>in</strong>g. Fuel amounts were reportedto be 40.7 t ha -1 for a deciduous broad-leaved forest mixedwith P<strong>in</strong>us densiflora <strong>in</strong> Shimane Prefecture (Su et al.,1995), and to be 15.2 t ha -1 for a 78-year-old Cryptomeriajaponica stand (Ohtsuka et al., 2006). On the other hand,much <strong>of</strong> the literature on folklore studies and culturaland social anthropology (e.g., Sasaki, 1972; Tachibana,1995) has described that for spr<strong>in</strong>g burn<strong>in</strong>g, the tim<strong>in</strong>g<strong>of</strong> slash<strong>in</strong>g and cutt<strong>in</strong>g fuel was <strong>in</strong> the previous summeror autumn, because <strong>of</strong> the long duration required to drythe fuel. Although fallow forests that were old or hadlarge amounts <strong>of</strong> aboveground biomass were used <strong>in</strong>spr<strong>in</strong>g burn<strong>in</strong>g, a significant portion <strong>of</strong> the biomass wasremoved to use as timber and fire wood. In areas proneto heavy snowfall, large-diameter trees were occasionallycut down on ground covered deeply with snow s<strong>in</strong>ce theycould easily be transported by us<strong>in</strong>g a sledge. In this case,because trees were typically cut at the snow-surface level,large stumps were left stand<strong>in</strong>g. In addition, some trunkswere kept aside, and after burn<strong>in</strong>g the rema<strong>in</strong><strong>in</strong>g fuel,these trunks were laid down along the contour l<strong>in</strong>es toprevent erosion and to create footholds on steep slopes. Incontrast, summer and autumn burn<strong>in</strong>gs were conductedafter dry<strong>in</strong>g the fuel for only 1–2 weeks, suggest<strong>in</strong>g thatyoung fallow forests with small amounts <strong>of</strong> the biomasswere used for this. Judg<strong>in</strong>g from these facts, relativelysmall amounts <strong>of</strong> fuel seem to have been burned <strong>in</strong>Japanese shift<strong>in</strong>g cultivation systems, perhaps around 50t ha -1 at most for a spr<strong>in</strong>g burn<strong>in</strong>g and 10–20 t ha -1 at mostfor summer and autumn burn<strong>in</strong>gs.Figure 1 shows the amounts <strong>of</strong> aboveground biomass<strong>in</strong> fallow forests that are <strong>under</strong> shift<strong>in</strong>g cultivation systemsby the Karen and Lua’ people <strong>in</strong> northern Thailand andMyanmar, and by several tribes <strong>in</strong> Borneo. In contrast, theactual fuel amounts for burn<strong>in</strong>g have seldom been reported.For the same number <strong>of</strong> fallow years, the amounts <strong>of</strong>aboveground biomass did not differ substantially betweenforests <strong>in</strong> Thailand and Myanmar and forests <strong>in</strong> Borneo,although they were generally higher <strong>in</strong> the former if threeBorneo plots with large biomass are excluded. It mightbe surmised that vegetation recovery <strong>in</strong> Thailand andBiomass(t ha -1 )Table 2. Aboveground biomass to be burned (fuels) <strong>in</strong> Japan.Forest conditionReference26.7 10 y fallow forest Sugawara and Sh<strong>in</strong>do (1985)18.5 7–8 y fallow forest Takahashi (1947)6.6 7–8 y fallow forest Takahashi (1947)40.7 Secondary forest after timber harvest<strong>in</strong>g Su et al. (1995)15.2 78-year-old C. japonica plantation after timber harvest<strong>in</strong>g Ohtsuka et al. (2006)
406S. Tanaka / Pedologist (2012) 403-414Fig. 1. Number <strong>of</strong> fallow years and the aboveground biomass <strong>of</strong> forests <strong>under</strong> shift<strong>in</strong>g cultivation systemsMyanmar is slow compared with Borneo, due to therebe<strong>in</strong>g less precipitation and severe dry seasons <strong>in</strong> theformer. However, Fukushima et al. (2007) reported that theKaren people’s method <strong>of</strong> cutt<strong>in</strong>g trunks at 1 m above theground when fell<strong>in</strong>g trees led to faster regrowth and thatthe growth <strong>of</strong> bamboo species <strong>in</strong> this region was vigorous,result<strong>in</strong>g <strong>in</strong> rapid recovery <strong>of</strong> aboveground biomass.Lua’ and Karen people are also reported to have cut <strong>of</strong>fbranches and left the trunk alive for large-diameter trees(Kunstadter, 1978). Traditionally, shift<strong>in</strong>g cultivators <strong>in</strong>Borneo would cut down trees at a po<strong>in</strong>t above the buttressroots <strong>in</strong> primary forests or old fallow forests. However,nowadays, shift<strong>in</strong>g cultivation systems are rarely used forsuch large forests and cultivators usually clear-cut fallowforests with a cha<strong>in</strong>saw. In addition to the differencebetween slash<strong>in</strong>g and cutt<strong>in</strong>g methods, higher soil nutrientcontent <strong>in</strong> Thailand (as discussed below) might alsocontribute to the fast biomass recovery. Thus, assum<strong>in</strong>gthat the amount <strong>of</strong> aboveground biomass is equivalent andthat tree species dom<strong>in</strong>ate fallow vegetation, the amount<strong>of</strong> fuel for burn<strong>in</strong>g is expected to be considerably higher <strong>in</strong>Borneo than <strong>in</strong> Thailand and Myanmar—at least <strong>under</strong> theKaren and Lua’ people’s systems.4. Soil temperature <strong>in</strong>crease dur<strong>in</strong>g burn<strong>in</strong>gFigure 2 plots the maximum soil temperaturesrecorded by a number <strong>of</strong> <strong>in</strong>vestigations dur<strong>in</strong>g burn<strong>in</strong>g<strong>in</strong> the three regions. Data (13) and (14) <strong>of</strong> Thailand andall Sarawak data were measured <strong>in</strong> shift<strong>in</strong>g cultivationexperiments by the current author (Tanaka et al., 2001;Kendawang et al., 2004; 2005). With<strong>in</strong> each region, the soiltemperature tended to be higher with <strong>in</strong>creas<strong>in</strong>g amounts<strong>of</strong> fuels. However, a comparison <strong>of</strong> temperatures and fuelamounts among regions shows that temperature <strong>in</strong>creaseswere considerably higher <strong>in</strong> Japan and Thailand than <strong>in</strong>Sarawak. The differences between soil temperature<strong>in</strong>creases might be expla<strong>in</strong>ed based on the position onthe slopes for ignition and the soil moisture conditions asfollows.For shift<strong>in</strong>g cultivation <strong>in</strong> Japan, the period for dry<strong>in</strong>gfuels was from several months to a half year for spr<strong>in</strong>gburn<strong>in</strong>g and one to two weeks for summer and autumnburn<strong>in</strong>gs. The amount <strong>of</strong> fuels seemed to be smallirrespective <strong>of</strong> the burn<strong>in</strong>g season. However, becauseburn<strong>in</strong>g was <strong>in</strong>itiated from an upper slope, the soil surfacecould be heated for a long duration, result<strong>in</strong>g <strong>in</strong> sufficienttime for heat transfer <strong>in</strong>to subsurface soils. Conversely,with soils usually moist, even <strong>in</strong> spr<strong>in</strong>g (a relativelydrier season), and with water hav<strong>in</strong>g a large specific heatcapacity and heat <strong>of</strong> vaporization, the soil temperaturecould <strong>in</strong>crease above 100 °C only for surface soils at adepth <strong>of</strong> about 1–2 cm. In Thailand, by burn<strong>in</strong>g time atthe end <strong>of</strong> the severe dry season (three months aftercutt<strong>in</strong>g), the fuels seem to be sufficiently dry. Although<strong>in</strong> the author’s experiment, fuels were ignited at a lowerslope, the positions for ignition were not reported fordata (9)–(12). In the author’s experiment, the fuels werealmost completely burned. Figure 2 <strong>in</strong>dicates that soiltemperatures at 2–3 cm depth could <strong>in</strong>crease to about100–200 °C because <strong>of</strong> the soil’s low moisture contentat the end <strong>of</strong> the dry season. In Sarawak, the period fordry<strong>in</strong>g fuels was commonly about 2–3 months, and so <strong>in</strong>experiments, large tree trunks were cut <strong>in</strong>to pieces <strong>of</strong> 1 mlength <strong>in</strong> order to hasten dry<strong>in</strong>g. Therefore, the fuels wereconsidered to be well-dried and the burn<strong>in</strong>g comparable
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics40798.5 t/ha45 t/ha34 t/ha18.5 t/ha16.6 t/ha15 t/haN.D.Large stemsBranches & leavesReburnReburn100 t/ha20 t/haN.D.300 t/ha100 t/ha300 t/ha100 t/ha300 t/ha100 t/haFig. 2. Soil temperature <strong>in</strong>crease dur<strong>in</strong>g burn<strong>in</strong>gto the shift<strong>in</strong>g cultivation system <strong>of</strong> the local people.However, soil temperature <strong>in</strong>creases were small, up toabout 100–150 °C at 3 cm depth even when burn<strong>in</strong>g 300t ha -1 <strong>of</strong> fuels. This small <strong>in</strong>crease is attributed to the fuelignition on the lower part <strong>of</strong> the slope as well as the moistsoils <strong>in</strong> the area. Irrespective <strong>of</strong> the region, <strong>in</strong>creases <strong>in</strong>soil temperature below a depth <strong>of</strong> 5 cm were negligible.5. Nutrient transfer from fuels to ashAsh addition by burn<strong>in</strong>g is widely accepted toalleviate soil acidity and fertilize soils to elevate nutrientcontent. However, only a portion <strong>of</strong> nutrients accumulated<strong>in</strong> aboveground biomass are transferred <strong>in</strong>to ash, and onlya proportion <strong>of</strong> those nutrients <strong>in</strong> the ash are <strong>in</strong>filtrated<strong>in</strong>to the soils.Nutrients <strong>in</strong> the aboveground biomass are released<strong>in</strong>to the atmosphere through volatilization or the dispersal<strong>of</strong> m<strong>in</strong>ute particles dur<strong>in</strong>g burn<strong>in</strong>g, where the extent <strong>of</strong>these losses is dependent on the type <strong>of</strong> nutrient and theburn<strong>in</strong>g conditions (Raison et al., 1985). Volatilizationtemperatures <strong>of</strong> typical soil nutrients are 277 °C for P, 774°C for K, 1,107 °C for Mg and 1,484 °C for Ca, althoughthese temperatures are different depend<strong>in</strong>g on theelements’ form. Several organic forms <strong>of</strong> N decompose ataround 200 °C and are released as NH 3 or NO x <strong>in</strong>to theatmosphere, whereas nitric acid is volatilized at 82.6 °C.Because fuel combustion temperatures are from severalhundred to more than one thousand degrees Celsius,the majority <strong>of</strong> N and a significant portion <strong>of</strong> P, K and Mgare lost due to volatilization. In contrast, temperaturesseldom exceed the level required for Ca volatilization.The rema<strong>in</strong><strong>in</strong>g nutrients dur<strong>in</strong>g burn<strong>in</strong>g are transferred<strong>in</strong>to the result<strong>in</strong>g ash and charcoal. However, a percentage<strong>of</strong> ash will also be lost due to updrafts dur<strong>in</strong>g burn<strong>in</strong>g.Few studies <strong>of</strong> shift<strong>in</strong>g cultivation systems <strong>in</strong> Japanand Southeast Asia have been concerned with nutrienttransfer from aboveground biomass to ash and from ash tosoils. Therefore, nutrient data compiled by Giard<strong>in</strong>a et al.(2000) <strong>in</strong> Central and South America are listed <strong>in</strong> Table 3with some modification. The percentage <strong>of</strong> each nutrienttransferred from vegetation <strong>in</strong>to ash were estimated to
408S. Tanaka / Pedologist (2012) 403-414AbovegroundBiomass(t ha -1 )Table 3. Nutrients <strong>in</strong> aboveground biomass and ash (Giard<strong>in</strong>a et al., 2000).Biomass nutrient (kg ha -1 ) Ash nutrient (kg ha -1 )N Ca Mg K P N Ca Mg K PMexico 110 944 1535 ND 346 27 28 696 ND 90 11Brazil 34 342 311 35 75 7 6 92 9 20 2Brazil 95 834 783 95 270 24 4 177 16 54 5Brazil 292 1390 90 ND 545 62 47 477 ND 211 18Brazil 361 2420 955 ND 500 62 40 486 ND 316 35ND: no data available.be 3% for N, 49% for P, 50% for Ca and 57% for K. Afterburn<strong>in</strong>g has been completed, a proportion <strong>of</strong> nutrientstransferred to the ash will then be lost due to w<strong>in</strong>d andrun<strong>of</strong>f water. Although scant data <strong>of</strong> such losses areavailable, <strong>in</strong> the case <strong>of</strong> Mexico <strong>in</strong> Table 3, the amounts<strong>of</strong> N and P that <strong>in</strong>filtrated <strong>in</strong>to soils were 7 and 5 kg ha -1 ,respectively (Giard<strong>in</strong>a et al., 2000).6. Effect <strong>of</strong> ash addition on soil propertiesAsh addition to soils elevates soil nutrient levelssuch as exchangeable base cations and available P. Levels<strong>of</strong> N are also <strong>in</strong>crease to an extent if vast amounts <strong>of</strong> fuelare burned. As discussed above, nutrient <strong>in</strong>put to soilsthrough ash addition is affected by various factors bothdur<strong>in</strong>g and after burn<strong>in</strong>g. Therefore, a detailed discussionabout absolute amounts <strong>of</strong> nutrients added to soils, orabsolute <strong>in</strong>creases <strong>in</strong> soil nutrient levels due to ash<strong>in</strong>puts, has little mean<strong>in</strong>g <strong>in</strong> comparison <strong>of</strong> the ash effectsamong regions, as <strong>in</strong> the present paper. In this section,the significance <strong>of</strong> ash addition effects on soil fertility isdiscussed <strong>in</strong> terms <strong>of</strong> the duration <strong>of</strong> these effects.Table 4 lists surface soil properties <strong>of</strong> areas <strong>under</strong>shift<strong>in</strong>g cultivation systems before burn<strong>in</strong>g and <strong>in</strong> fallowTable 4. Surface soil properties <strong>of</strong> areas <strong>under</strong> shift<strong>in</strong>g cultivation systems before burn<strong>in</strong>g or <strong>under</strong> fallow.Depth pH T-N CEC Exchangeable cations Available ReferenceCa Mg K P(cm) (g kg -1 ) (cmol ckg -1 ) (mg kg -1 )JapanIwate* 0–5 4.98 28.6 0.47 0.45 0.11 ND Sugawara and Sh<strong>in</strong>do (1982)Iwate* 0–5 5.10 28.7 0.42 0.49 0.10 ND Sugawara and Sh<strong>in</strong>do (1983)Iwate* 0–5 5.00 29.3 0.37 0.44 0.11 ND Sugawara and Sh<strong>in</strong>do (1985)Niigata* 0–5 5.60 5.0 ND 17.4 5.45 1.90 7.07 Ohtsuka et al. (2006)ThailandKhon Kaen* 0–5 6.3 3.0 20.3 16.1 5.9 0.4 6.67 Tulaphitak et al. (1983)Mae Hong Son** (Sedimentary) 0–10 5.90 2.7 17.2 3.15 2.09 0.76 5.02 Funakawa et al. (1997)Mae Hong Son** (Granite) 0–10 5.85 3.3 17.0 1.85 1.75 0.67 5.45 Funakawa et al. (1997)Sarawak, MalaysiaBalai R<strong>in</strong>g<strong>in</strong>* 0–5 4.01 3.4 19.4 0.19 0.26 0.2 5.3 Tanaka et al. (2004)Sabal* 0–5 4.77 2.2 4.88 0.04 0.34 0.08 3.6 Tanaka et al. (2004)Niah* 0–5 4.62 2.2 14.9 1.25 1.01 0.43 13.8 Tanaka et al. (2005)Mujong** 0–10 4.95 2.6 20.4 0.83 0.79 0.28 7.5 Tanaka et al. (2007)ND: no data available; *before burn<strong>in</strong>g; **average values <strong>of</strong> fallow forests <strong>of</strong> various ages.T-N: total nitrogen; CEC: cation exchange capacity.
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics409forests. In spite <strong>of</strong> the limited available data and theexceptions <strong>in</strong> those data, the pH and exchangeable cationlevels were <strong>in</strong> general highest <strong>in</strong> Thailand, followed byJapan and then Sarawak. The levels <strong>of</strong> available P werelow <strong>in</strong> all regions. The level <strong>of</strong> CEC was highest <strong>in</strong> Japan,suggest<strong>in</strong>g a larger content than <strong>in</strong> the other regions<strong>of</strong> soil organic matter and 2:1 type clay m<strong>in</strong>erals. Fromthese properties, the <strong>in</strong>herent soil fertility level <strong>in</strong> terms<strong>of</strong> soil pH and nutrients is considered to be higher <strong>in</strong>Thailand than <strong>in</strong> Japan and Sarawak. Table 5 comparesthe soil nutrient stocks at several <strong>of</strong> sites listed <strong>in</strong> Table4, calculated from the soil properties at depths <strong>of</strong> 0–5 cmor 0–10 cm. Relat<strong>in</strong>g the soil nutrient stocks <strong>in</strong> Table 5with the ash nutrients <strong>in</strong> Table 3, the burn<strong>in</strong>g <strong>of</strong> only 50 tha -1 <strong>of</strong> fuels <strong>in</strong> Japan (spr<strong>in</strong>g burn<strong>in</strong>g) and Sarawak (abouthalf <strong>of</strong> the fuel amounts burned <strong>in</strong> Mexico (110 t ha -1 )or Brazil (95 t ha -1 )) would be expected to substantiallyelevate soil nutrient levels. For the summer and autumnburn<strong>in</strong>gs <strong>in</strong> Japan, ash effects are considered somewhatunlikely because the amounts <strong>of</strong> the fuel are thought to be10–20 t ha -1 as discussed <strong>in</strong> Section 3. In contrast, becausethe levels <strong>of</strong> soil nutrients are orig<strong>in</strong>ally relatively high <strong>in</strong>Thailand, ash effects might not be appreciable, althoughthe alkal<strong>in</strong>e components could play an important role <strong>in</strong>alleviat<strong>in</strong>g the acidity levels <strong>in</strong> the subsoils (Funakawa etal., 1997).Table 6 lists the duration after which elevated pH andnutrients levels due to ash addition return to their <strong>in</strong>itialpre-burn<strong>in</strong>g levels. In Japan, accord<strong>in</strong>g to a series <strong>of</strong> studiesby Sugawara and S<strong>in</strong>do (1982; 1983; 1985), this period wastypically after three to four years (third or fourth harvest).However, <strong>in</strong> many cases, the levels still rema<strong>in</strong>ed high atthe last measurement. In Ohtsuka et al.’s study (2006),the levels <strong>of</strong> pH, exchangeable Ca and available P werestill elevated at the end <strong>of</strong> their measurement period(three months after burn<strong>in</strong>g). In the cases <strong>of</strong> ThailandTable 5. Nutrient stocks <strong>of</strong> surface soils before burn<strong>in</strong>g.Depth T-N Exchangeable (kg ha -1 ) Available Reference(cm) (kg ha -1 ) Ca Mg K P (kg ha -1 )Iwate, Japan 0–5 ND 47.0 27.3 21.5 ND Sugawara and Sh<strong>in</strong>do (1982)Mae Hong Son, Thailand 0–10 2700 630 240 297 5.0 Funakawa et al. (1997)Balai R<strong>in</strong>g<strong>in</strong>, Sarawak 0–10 3200 25.5 21.9 63.6 3.9 Tanaka et al. (2004)Mujong, Sarawak 0–10 2750 166 91 109 7.5 Tanaka et al. (2007)The bulk density <strong>in</strong> calculation was assumed to be 1.0 g mL -1 .Table 6. Duration after which elevated pH and nutrients levels due to ash addition returned to <strong>in</strong>itial pre-burn<strong>in</strong>g levels.Measurement <strong>in</strong>tervals pH Exchangeable Available ReferenceCa Mg K PMonths after burn<strong>in</strong>gJapanIwate 1, 7, 19, 31, 43 19 31 43 19 ND Sugawara and Sh<strong>in</strong>do (1982)Iwate 1, 4, 16, 28, 40 40 NR NR NR ND Sugawara and Sh<strong>in</strong>do (1983)Iwate 1, 4, 16, 28, 40 28 NR 16 NR ND Sugawara and Sh<strong>in</strong>do (1985)Niigata 0, 0.25, 1, 2, 3 NR NR 1 2 NR Ohtsuka et al. (2006)ThailandKhon Kaen 0, 3, 8, 11, 16, 18, 22 11 ND ND 8 NR Tulaphitak et al. (1983)Sarawak, MalaysiaBalai R<strong>in</strong>g<strong>in</strong> 0, 3, 7, 12 12 NR NR 12 7 Tanaka et al. (2004)Sabal 0, 3, 7, 12 3 NR 7 7 7 Tanaka et al. (2004)Niah 0, 1, 3, 7, 12 NR NR 3–7 7 3–7 Tanaka et al. (2005)NR: not returned to; ND: no data available
410S. Tanaka / Pedologist (2012) 403-414(Tulaphitak et al., 1983) and Sarawak (Tanaka et al.,2004, 2005), elevated pH, exchangeable K and Mg, andavailable P returned to the <strong>in</strong>itial levels by harvest<strong>in</strong>gtime, or with<strong>in</strong> one year. Despite evidence be<strong>in</strong>g scarcedue to the lack <strong>of</strong> <strong>in</strong>formation, several potential reasonsfor the differences seen <strong>in</strong> the duration <strong>of</strong> ash effects aretentatively proposed as follows. The first reason is thedifference between clay m<strong>in</strong>eralogical composition andthe charge characteristics <strong>of</strong> the soils <strong>under</strong> differentclimates. The second reason is that leach<strong>in</strong>g <strong>of</strong> ashnutrients might be more severe <strong>in</strong> Thailand and Sarawakthan <strong>in</strong> Japan. Although the annual precipitation is similar<strong>in</strong> Thailand and Japan, cropp<strong>in</strong>g <strong>in</strong> Thailand occurred <strong>in</strong>the ra<strong>in</strong>y season. The third reason is that the differencemight be partially attributed to the geographical location<strong>of</strong> Japan, which is adjacent to the Ch<strong>in</strong>ese cont<strong>in</strong>ent andsurrounded by ocean—the passageway <strong>of</strong> many typhoons.The annual amounts <strong>of</strong> nutrients passed to soils byprecipitation <strong>in</strong> Kochi Prefecture have been reported tobe 5.3 kg ha -1 for Ca, 3.1 kg ha -1 for Mg and 2.6 kg ha -1for K (Yamada et al., 2004), suggest<strong>in</strong>g that <strong>in</strong> comparisonwith the amounts <strong>of</strong> nutrients conta<strong>in</strong>ed <strong>in</strong> ash and soils,an appreciable amount <strong>of</strong> nutrients can be added throughprecipitation. At a location fac<strong>in</strong>g or near the ocean, seasalts can also be added dur<strong>in</strong>g the pass<strong>in</strong>g <strong>of</strong> a typhoon.In addition, nutrient addition through dry deposition canbe expected. Inoue et al. (1998) reported that yellow sandphenomenon derived from the Ch<strong>in</strong>ese cont<strong>in</strong>ent couldtransport nutrients, such as Ca, to Japan.7. Soil burn<strong>in</strong>g effectThe soil burn<strong>in</strong>g effect is a phenomenon <strong>in</strong> which theNH 4 -N level <strong>of</strong> soils is <strong>in</strong>creased dur<strong>in</strong>g burn<strong>in</strong>g and theN m<strong>in</strong>eralization is stimulated after burn<strong>in</strong>g. Note thatthe soil burn<strong>in</strong>g effect <strong>in</strong> situ implicitly <strong>in</strong>cludes somecontribution from ash <strong>of</strong> m<strong>in</strong>eral N and the stimulation <strong>of</strong>N m<strong>in</strong>eralization as a result <strong>of</strong> <strong>in</strong>creased soil temperaturedue to removal <strong>of</strong> forest cover. Although the majority <strong>of</strong>previous studies on the soil burn<strong>in</strong>g effect have beenconcerned only with N, <strong>in</strong>creases <strong>in</strong> other nutrients byheat<strong>in</strong>g, such as available P and exchangeable K, can bealso <strong>in</strong>cluded (Andriesse and Koopmans, 1984). Accord<strong>in</strong>gto Sakamoto et al. (1993) and Simamoto et al. (1995), the<strong>in</strong>crease <strong>in</strong> NH 4 -N can be attributed to a deam<strong>in</strong>ationreaction caused by heat<strong>in</strong>g. Those authors also <strong>in</strong>dicatedthat the amounts <strong>of</strong> both NH 4 -N and easily decomposableorganic N beg<strong>in</strong> to <strong>in</strong>crease at a relatively low temperature<strong>of</strong> 50 °C. Furthermore, they suggested that, whereas Nfractions at around 50 °C are derived ma<strong>in</strong>ly from themicrobial debris result<strong>in</strong>g from soil heat<strong>in</strong>g, the proportion<strong>of</strong> N orig<strong>in</strong>at<strong>in</strong>g from soil organic matter <strong>in</strong>creases withtemperature above 100 °C. Accord<strong>in</strong>g to a series <strong>of</strong> studiesconducted by Mitsui et al. dur<strong>in</strong>g World War II (Moritsukaand Matsuoka, 2008), the maximum levels <strong>of</strong> NH 4 -N andN m<strong>in</strong>eralization were recorded at 200 °C, and the levelsFig. 3. M<strong>in</strong>eral nitrogen levels <strong>in</strong> slash and burn experiments <strong>in</strong> Otoyo town, Kochi Prefecture, Japan, <strong>in</strong>northern Thailand and <strong>in</strong> Sarawak
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics411decreased at temperatures <strong>of</strong> more than 300 °C. NO 3 -N disappeared at 200 °C. Although these studies wereconducted <strong>under</strong> laboratory conditions, the temperatureswere mostly with<strong>in</strong> the range reported dur<strong>in</strong>g burn<strong>in</strong>g <strong>in</strong>shift<strong>in</strong>g cultivation systems (Table 2).Figure 3 reveals changes <strong>in</strong> m<strong>in</strong>eral N levels <strong>of</strong>0–5-cm soils dur<strong>in</strong>g slash and burn experiments by thepresent author <strong>in</strong> Otoyo Town, Kochi Prefecture, Japan(unpublished data), <strong>in</strong> northern Thailand (Tanaka etal. 2001) and <strong>in</strong> Sarawak (Kendawang et al., 2005). Soilsamples were collected from reburned spots <strong>in</strong> KochiPrefecture, and from plots after 100 t ha -1 fuel burn<strong>in</strong>gs <strong>in</strong>Thailand and Sarawak. The soil moisture content beforeburn<strong>in</strong>g and the maximum temperature dur<strong>in</strong>g burn<strong>in</strong>gwere 35% and 90 °C (temperature measured at 3 cm depth)<strong>in</strong> Kochi Prefecture, 17% and 297 °C (2.5 cm) <strong>in</strong> Thailand,and 38% and 70 °C (3 cm) <strong>in</strong> Sarawak, respectively. Beforeburn<strong>in</strong>g, the levels <strong>of</strong> m<strong>in</strong>eral N and the proportions <strong>of</strong>NO 3 -N <strong>in</strong> the m<strong>in</strong>eral N were higher <strong>in</strong> Kochi Prefectureand Sarawak than <strong>in</strong> Thailand, suggest<strong>in</strong>g that the formerhad higher soil microbial activities due to preferableconditions and high soil moisture contents. The amount<strong>of</strong> NH 4 -N was <strong>in</strong>creased by the soil burn<strong>in</strong>g effect <strong>in</strong> allregions. The NH 4 -N level was highest <strong>in</strong> Kochi Prefecture,and is attributed to the higher soil organic matter <strong>in</strong> thisregion and the longer heat<strong>in</strong>g duration due to burn<strong>in</strong>gfrom an upper slope and reburn<strong>in</strong>g. However, compar<strong>in</strong>gthe pre-burn<strong>in</strong>g levels, the <strong>in</strong>crease <strong>in</strong> NH 4 -N was moreremarkable <strong>in</strong> Thailand, followed by Japan and Sarawak,reflect<strong>in</strong>g the differences <strong>in</strong> soil moisture content and<strong>in</strong> the soil temperature <strong>in</strong>crease. Nitrate N levels weredecreased by burn<strong>in</strong>g <strong>in</strong> all cases, especially for Sarawak,which partially <strong>of</strong>fset the benefit <strong>of</strong> NH 4 -N <strong>in</strong>creases.Nitrification activities recovered at a relatively earlystage <strong>of</strong> cropp<strong>in</strong>g. Note that <strong>in</strong> all regions, the soil burn<strong>in</strong>geffect dim<strong>in</strong>ished dur<strong>in</strong>g a s<strong>in</strong>gle crop cycle, suggest<strong>in</strong>gexhaustion <strong>of</strong> the available N pool.Accord<strong>in</strong>g to Japanese farmers’ perceptions, reburn<strong>in</strong>gresulted <strong>in</strong> high crop productivity (Sasaki, 1972; Nomoto,1984). Based on the author’s observations, the color<strong>of</strong> surface soil at around a depth <strong>of</strong> 1 cm occasionallychanges to red or brown at such reburned spots, as wellas at well-burned po<strong>in</strong>ts <strong>of</strong> a s<strong>in</strong>gle burn<strong>in</strong>g, <strong>in</strong>dicat<strong>in</strong>gthe combustion <strong>of</strong> soil organic matter and the result<strong>in</strong>gloss <strong>of</strong> N. Although, to the author’s best knowledge, an<strong>in</strong>vestigation <strong>of</strong> this phenomenon has not been conducted,such perception might be expla<strong>in</strong>ed thusly: a significantamount <strong>of</strong> N supplied from thick ash deposition at suchpo<strong>in</strong>ts may <strong>of</strong>fset the loss <strong>of</strong> soil N by burn<strong>in</strong>g. In addition,heat can be conducted to deeper soil layers dur<strong>in</strong>greburn<strong>in</strong>g and the soil burn<strong>in</strong>g effect may occur theretoo.Although the soil burn<strong>in</strong>g effect is <strong>in</strong>dispensablefor crop production <strong>under</strong> a shift<strong>in</strong>g cultivation systemwithout fertilizer application, the nature <strong>of</strong> the effect canbe thought <strong>of</strong> as squeez<strong>in</strong>g the soils’ available N pools tosupply m<strong>in</strong>eral N to crops at the expense <strong>of</strong> NO 3 -N.8. ConclusionBy tak<strong>in</strong>g <strong>in</strong>to account the variations between regionalash effects and soil burn<strong>in</strong>g effects, as discussed above,the differences between shift<strong>in</strong>g cultivation systems<strong>under</strong> temperate (Japan), tropical monsoon (Thailand) andtropical ra<strong>in</strong> forest (Sarawak) climatic conditions can be<strong>in</strong>terpreted as follows. In Japan, ash effects that elevatethe levels <strong>of</strong> exchangeable cations and available P can lastfor a long duration (three to four years after burn<strong>in</strong>g). Ifthe ability <strong>of</strong> soils to supply N, which decreases dur<strong>in</strong>gcropp<strong>in</strong>g, can be compensated for, cropp<strong>in</strong>g can cont<strong>in</strong>ue.Such compensation is the reason for cropp<strong>in</strong>g beans <strong>in</strong>the third and fourth years <strong>in</strong> Japan (Table 1). In Thailand,although the soil burn<strong>in</strong>g effect is important for cropproduction, ash effects might be relatively unimportantbecause <strong>of</strong> the <strong>in</strong>herently high level <strong>of</strong> soil nutrients thatalready exist. In contrast, <strong>in</strong> Sarawak, ash effects areimportant to alleviate soil acidity and supply basic cationsand P dur<strong>in</strong>g crop production, but the soil burn<strong>in</strong>g effectmight be relatively <strong>in</strong>significant. Farmers <strong>in</strong> Thailandand Sarawak must abandon their fields after one cropbecause <strong>of</strong> the decrease <strong>in</strong> available N <strong>in</strong> Thailand, and thedecreases <strong>in</strong> all nutrients <strong>in</strong> Sarawak.Although only a rough comparison could be performed<strong>in</strong> this study because <strong>of</strong> the lack <strong>of</strong> available data, further<strong>in</strong>vestigation can contribute to our <strong>under</strong>stand<strong>in</strong>g <strong>of</strong> therole <strong>of</strong> fallow periods <strong>under</strong> low <strong>in</strong>put shift<strong>in</strong>g cultivationsystems, as well as to clarify<strong>in</strong>g the mechanisms <strong>of</strong> landdegradation <strong>under</strong> <strong>in</strong>tensified systems. Presently <strong>in</strong>
412S. Tanaka / Pedologist (2012) 403-414Japan, shift<strong>in</strong>g cultivation systems are be<strong>in</strong>g reconsideredbecause <strong>of</strong> their environmental friendly aspects and low<strong>in</strong>puts. Several trials have been carried out <strong>in</strong> order torestore shift<strong>in</strong>g cultivation practices, for example, as apart <strong>of</strong> green tourism or crop production similar to organicfarm<strong>in</strong>g. Such trials provide an opportunity to reexam<strong>in</strong>ethe nutrient dynamics <strong>in</strong> a Japanese shift<strong>in</strong>g cultivationsystem and to compare this with different systems <strong>in</strong>different regions.ReferencesAndriesse, J. P. and Koopmans, T. Th. 1984. A monitor<strong>in</strong>gstudy on nutrient cycles <strong>in</strong> soils used for shift<strong>in</strong>gcultivation <strong>under</strong> various climatic conditions <strong>in</strong> tropicalAsia. I. The <strong>in</strong>fluence <strong>of</strong> simulated burn<strong>in</strong>g on form andavailability <strong>of</strong> plant nutrients. Agriculture, Ecosystemsand Environment, 12: 1-16.Ch<strong>in</strong>, S. C. 1985. Agriculture and resource utilization <strong>in</strong>a lowland ra<strong>in</strong>forest Kenyah community. The SarawakMuseum Journal, 56: 1-322.Conkl<strong>in</strong>, H. 1957. Hanunóo Agriculture. A report onan Integral System <strong>of</strong> Shift<strong>in</strong>g <strong>Cultivation</strong> <strong>in</strong> thePhilipp<strong>in</strong>es, p. 209, FAO Forestry Development paperNo. 12. FAO, Rome.Dove, M. R. 1981. Subsistence Strategies <strong>in</strong> Ra<strong>in</strong> ForestSwidden Agriculture: The Kantu’ at Tikul Batu,Volume 1, p. 499, University Micr<strong>of</strong>ilms International,Michigan.Freeman, D. 1970. Report on the Iban, p. 317, Monographson Social Anthropology 41, Athlone Press, London.Fukui, K. 1974. Yakihata no Mura, p. 418, Asahish<strong>in</strong>bunsha,Tokyo (<strong>in</strong> Japanese).Fukushima, M., Kanzaki, M., Hla, M.T. and Yazar, M. 2007.Recovery process <strong>of</strong> fallow vegetation <strong>in</strong> the traditionalKaren swidden cultivation system <strong>in</strong> the Bago mounta<strong>in</strong>range, Myanmar. Southeast Asian Studies, 45: 317-333.Fukushima, M., Kanzaki, M., Hara, M., Ohkubo, T.,Preechapanya, P. and Choocharoen, C. 2008. Secondaryforest succession after the cessation <strong>of</strong> swiddencultivation <strong>in</strong> the montane forest area <strong>in</strong> NorthernThailand. Forest Ecology and Management, 255: 1994-2006.Funakawa, S., Tanaka, S., Kaewkhongkha, T., Hattori, T.and Yonebayashi, K. 1997. Physicochemical properties <strong>of</strong>the soils associated with shift<strong>in</strong>g cultivation <strong>in</strong> northernThailand with special reference to factors determ<strong>in</strong><strong>in</strong>gsoil fertility. Soil Science and Plant Nutrition, 43: 665-679.Giard<strong>in</strong>a, C. P., Sanford Jr., R. L., Døckersmith, I. C. andJaramillo, V. J. 2000. The effects <strong>of</strong> slash and burn<strong>in</strong>g onecosystem nutrients dur<strong>in</strong>g the land preparation phase<strong>of</strong> shift<strong>in</strong>g cultivation. Plant and Soil, 220: 247-260.Hashimoto, T., Kojima, K., Tange, T. and Sasaki, S.2000. Changes <strong>in</strong> carbon storage <strong>in</strong> fallow forests <strong>in</strong>the tropical lowlands <strong>of</strong> Borneo. Forest Ecology andManagement, 126: 331-337.Inoue, K., Hamaura, H., Hiradate, S. and Kasai, O. 1998.<strong>Influence</strong> <strong>of</strong> Asian Long-Range Eolian Dust on ChemicalComponents and Inorganic Dust Deposits <strong>of</strong> Ra<strong>in</strong>water<strong>in</strong> Northeast Japan. Japanese Journal <strong>of</strong> Soil Science andPlant Nutrition, 69: 445-456 (<strong>in</strong> Japanese with Englishsummery).Ipor, I. B. and Tawan, C. S. 2004. Succession <strong>of</strong> fallowsafter shift<strong>in</strong>g cultivation <strong>in</strong> Sungai Sarawak bas<strong>in</strong>,Kuch<strong>in</strong>g, Sarawak. Proceed<strong>in</strong>gs from IUFRO Divison 5,Research Groups 5.11 and 5.12, 3: 19-27.Kamada, M., Nakagoshi, N. and Takahashi, F. 1987. Effects<strong>of</strong> burn<strong>in</strong>g on germ<strong>in</strong>ation <strong>of</strong> viable seeds <strong>in</strong> a slash andburn agriculture soil. Japanese Journal <strong>of</strong> Ecology, 37:91-100 (<strong>in</strong> Japanese with English summery).Kendawang, J.J., N<strong>in</strong>omiya, I., Kenzo, T., Ozawa, T.,Hattori, D., Tanaka, S., and Sakurai, K. 2007. Effects<strong>of</strong> burn<strong>in</strong>g strength <strong>in</strong> shift<strong>in</strong>g cultivation on the earlystage <strong>of</strong> secondary succession <strong>in</strong> Sarawak, Malaysia.Tropics, 16, 309-321.Kendawang, J. J., Tanaka, S., Ishihara, J., Shibata, K.,Sabang, J., N<strong>in</strong>omiya, I., Ishizuka, S. and Sakurai, K.2004. Effects <strong>of</strong> shift<strong>in</strong>g cultivation on soil ecosystems<strong>in</strong> Sarawak, Malaysia. I. Slash and burn<strong>in</strong>g at BalaiR<strong>in</strong>g<strong>in</strong> and Sabal Experimental sites and effect on soilorganic matter. Soil Science and Plant Nutrition, 50:677-687.Kendawang, J. J., Tanaka, S., Shibata, K., Yoshida, N.,Sabang, J., N<strong>in</strong>omiya, I. and Sakurai, K. 2005. Effects<strong>of</strong> shift<strong>in</strong>g cultivation on soil ecosystems <strong>in</strong> Sarawak,Malaysia. III. Results <strong>of</strong> burn<strong>in</strong>g practice and changes<strong>in</strong> soil organic matter at Niah and Bakam experimental
S. Tanaka: <strong>Influence</strong> <strong>of</strong> burn<strong>in</strong>g <strong>in</strong> shift<strong>in</strong>g cultivation on nutrient dynamics413sites. Soil Science and Plant Nutrition, 51: 515-523.Kiyono, Y. and Hastaniah 2005. Patterns <strong>of</strong> slash-andburnland use and their effects on forest succession–Swidden-land forests <strong>in</strong> Borneo-. Bullet<strong>in</strong> <strong>of</strong> Forestryand Forest Products Research Institute, 4: 259-282.Kunstadter, P. 1978. Subsistence agricultural economics<strong>of</strong> Lua’ and Karen hill farmers, Mae Sariang District,Northwestern Thailand. In P. Kunstadter, E. C.Chapman, and S. Sabhasri Eds. “Farmers <strong>in</strong> the Forest”,pp. 74-131, the University Press <strong>of</strong> Hawaii, Honolulu.Matsui, Y. 1946. Yakihata Kaikon, p. 192, Hoppoushuppansha,Sapporo (<strong>in</strong> Japanese).Moritsuka, N. and Matsuoka, K. 2008. Past and presentstudies on the agronomic effects <strong>of</strong> soil heat<strong>in</strong>g.Japanese Journal <strong>of</strong> Soil Science and Plant Nutrition, 79:505-510 (<strong>in</strong> Japanese with English summery).Nomoto, K. 1985. Yakihatam<strong>in</strong>zokubunkaron, p. 680,Yuzankaku, Tokyo (<strong>in</strong> Japanese).Ohtsuka, T., Mo, W., Uchida, M., Sako, H. and Koizumi, H.2006. Slash-and burn agriculture <strong>in</strong> a Japanese Cedar(Cryptomeria japonica D. Don) Plantation: Effects <strong>of</strong>fire on nutrients and soil emissions <strong>of</strong> carbon dioxide.Elsevier Oceanography Series 73: 395-416.Pair<strong>in</strong>tra, C. and Kyuma, K. 1983. Chapter 2. Description<strong>of</strong> the experimental site. In K. Kyuma and C. Pair<strong>in</strong>traEds. “Shift<strong>in</strong>g cultivation. An Experiment at NamPhrom, Northeast Thailand, and Its Implications forUpland Farm<strong>in</strong>g <strong>in</strong> the Monsoon Tropics”, pp. 7-12,Faculty <strong>of</strong> Agriculture, KyotoUniversity, Kyoto.Raison, R.J., Khanna, P.K., and Woods, P.V. 1985.Mechanisms <strong>of</strong> element transfer to the atmospheredur<strong>in</strong>g vegetation fires. Canadian Journal <strong>of</strong> ForestResearch, 15: 132-140.Sabhasri, S. 1978. Effects <strong>of</strong> forest fallow cultivationon forest production and soil. In P. Kunstadter, E. C.Chapman, and S. Sabhasri Eds. “Farmers <strong>in</strong> the Forest”,pp. 160-174, the University Press <strong>of</strong> Hawaii, Honolulu.Sakamoto, K., Shimamoto, M. and Yoshida, T. 1993. TheComposition and Orig<strong>in</strong> <strong>of</strong> the Extractable OrganicSubstances <strong>in</strong> Heated Soils. Japanese Journal <strong>of</strong> SoilScience and Plant Nutrition, 64: 9-14 (<strong>in</strong> Japanese withEnglish summery).Sasaki, K. 1972. Nihon no Yakihata –Sono ChiikitekiHikakukenkyuu-, p.457, Kokonsho<strong>in</strong>, Tokyo (<strong>in</strong>Japanese).Shimamoto, M., Sakamoto, K. and Yoshida, T. 1995. TheContribution <strong>of</strong> Microbial Biomass N to Available SoilN <strong>in</strong> Heated Soils. Japanese Journal <strong>of</strong> Soil Science andPlant Nutrition, 66: 27-31 (<strong>in</strong> Japanese with Englishsummery).Su, J., Katagiri, S., Kaneko, N. and Nagayama, Y. 1995.Changes <strong>of</strong> soil temperature and ash<strong>in</strong>g extent <strong>of</strong> organicmatter dur<strong>in</strong>g the burn<strong>in</strong>g <strong>of</strong> forest floor. Transaction <strong>of</strong>Kansai Branch <strong>of</strong> Japanese Forestry Society, 4: 53-54 (<strong>in</strong>Japanese with English summery).Sugawara, S. and Sh<strong>in</strong>do, T. 1982. Studies <strong>in</strong> cropp<strong>in</strong>gsystem <strong>of</strong> slash-and-burn method <strong>of</strong> agriculture andits orig<strong>in</strong>. X. Effects <strong>of</strong> plant<strong>in</strong>g <strong>in</strong>tervals <strong>of</strong> Perillafrutescens Britton on weed vegetation <strong>in</strong> slash-and-burnfield. Farm Work Research, 45: 16-24 (<strong>in</strong> Japanese).Sugawara, S. and Sh<strong>in</strong>do, T. 1983. Studies <strong>in</strong> cropp<strong>in</strong>gsystem <strong>of</strong> slash-and-burn method <strong>of</strong> agriculture and itsorig<strong>in</strong>. XII. Weed restra<strong>in</strong><strong>in</strong>g effects <strong>of</strong> burned ash <strong>in</strong>some species <strong>of</strong> wood. Farm Work Research, 48: 9-16(<strong>in</strong> Japanese).Sugawara, S. and Sh<strong>in</strong>do, T. 1985. Studies <strong>in</strong> cropp<strong>in</strong>gsystem <strong>of</strong> slash-and-burn method <strong>of</strong> agricultureand its orig<strong>in</strong>. XVI. On the shifts <strong>in</strong> vegetation <strong>in</strong>the abandonment after slash-and-burn. Farm WorkResearch, 54: 73-80 (<strong>in</strong> Japanese).Sugawara, S. and Sh<strong>in</strong>do, T. 1988. Studies <strong>in</strong> cropp<strong>in</strong>gsystem <strong>of</strong> slash-and-burn method <strong>of</strong> agriculture andits orig<strong>in</strong>. XX. Effects <strong>of</strong> burn<strong>in</strong>g on weed restra<strong>in</strong>.Japanse Journal <strong>of</strong> Farm Work Research, 23: 111-116(<strong>in</strong> Japanese).Tachibana, R. 1995. Hakusanroku no Yakihatanoukou.Sono M<strong>in</strong>zokugakuteki Seitaishi, p.666, Hakusuisha,Tokyo (<strong>in</strong> Japanese).Takahashi, Y. 1947. Yamagata kennka niokeru yakihatachousa seiseki. Tohokunougyou, 1: 28-23 (<strong>in</strong> Japanese).Tanaka, S., Ando, T., Funakawa, S., Sukhrun, C.,Kaewkhongkha, T. and Sakurai, K. 2001. Effect<strong>of</strong> burn<strong>in</strong>g on soil organic matter content and Nm<strong>in</strong>eralization <strong>under</strong> shift<strong>in</strong>g cultivation system <strong>of</strong>Karen people <strong>in</strong> northern Thailand. Soil Science andPlant Nutrition, 47: 547-558.Tanaka, S., Kendawang, J. J., Ishihara, J., Shibata, K., Kou,A., Jee, A., N<strong>in</strong>omiya, I. and Sakurai, K. 2004. Effects
414S. Tanaka / Pedologist (2012) 403-414<strong>of</strong> shift<strong>in</strong>g cultivation on soil ecosystems <strong>in</strong> Sarawak,Malaysia. II. Changes <strong>in</strong> soil chemical properties andrun<strong>of</strong>f water at Balai R<strong>in</strong>g<strong>in</strong> and Sabal Experimentalsites. Soil Science and Plant Nutrition, 50: 689-699.Tanaka, S., Kendawang, J. J., Yoshida, N., Shibata, K.,Jee, A., Tanaka, K., N<strong>in</strong>omiya, I. and Sakurai, K. 2005.Effects <strong>of</strong> shift<strong>in</strong>g cultivation on soil ecosystems <strong>in</strong>Sarawak, Malaysia. IV. Chemical properties <strong>of</strong> the soilsand run<strong>of</strong>f water at Niah and Bakam experimental sites.Soil Science and Plant Nutrition, 51: 525-533.Tanaka, S., Wasli, M.E., Seman, L., Jee, A., Kendawang, J.J., Sakurai, K. and Morooka, Y. 2007. Soil properties <strong>of</strong>secondary forests <strong>under</strong> shift<strong>in</strong>g cultivation by the Iban<strong>of</strong> Sarawak, Malaysia <strong>in</strong> relation to vegetation condition.Tropics, 16: 385-398.Tulaphitak, T., Pair<strong>in</strong>tra, C. and Kyuma, K. 1983. Chapter4. Soil fertility and tilth. In K. Kyuma and C. Pair<strong>in</strong>traEds. “Shift<strong>in</strong>g cultivation. An Experiment at NamPhrom, Northeast Thailand, and Its Implications forUpland Farm<strong>in</strong>g <strong>in</strong> the Monsoon Tropics”, pp. 63-83,Faculty <strong>of</strong> Agriculture, KyotoUniversity, Kyoto.Yamada, T., Morisada, K., Sakai, A., Yosh<strong>in</strong>aga, S., Hirai, K.,Kato, M., Yoshida, K., Iwagawa, O., Miura, S., Inagaki,Y., Sh<strong>in</strong>omiya, Y., Takeuchi, I., Tabuchi, R., Sakai,T., Kuramoto, S., Mori, S., Ohguro, T., Kawasaki, T.,Matsumura, N., Kodani, E., Yoshida, M., Miyamoto, T.,Tsuzuki, N., Yamada, S., Imatomi, Y., M<strong>in</strong>eo, K., Yamazaki,S., Inoue, T., Tabata, M., Abe, Y., Hirota, T. and Kadota,H. 2004. Monitor<strong>in</strong>g <strong>of</strong> acidic precipitation’s effects onforest ecosystems -monitor<strong>in</strong>g <strong>of</strong> the ra<strong>in</strong> and forest <strong>in</strong>the h<strong>in</strong>oki stand <strong>in</strong> the Shikoku area-. Bull. FFPRI., 3:365-407 (<strong>in</strong> Japanese with English summery).Y<strong>in</strong>, S. T. 2000. Unnan no Yakihara. J<strong>in</strong>ruiseitaigakutekiKenkyu, p.238, Nour<strong>in</strong>toukeikyoukai, Tokyo (<strong>in</strong>Japanese).Z<strong>in</strong>ke, P.J., Sabhasri, S. and Kunstadter, P. 1978. Soilfertility aspects <strong>of</strong> the Lua’ forest fallow system <strong>of</strong>shift<strong>in</strong>g cultivation. In P. Kunstadter, E. C. Chapman,and S. Sabhasri Eds. “Farmers <strong>in</strong> the Forest”, pp. 134-159, the University Press <strong>of</strong> Hawaii, Honolulu.