TheImprovement ofTropical and Subtropical Rangelands

POTENTIAL OF FAIDHERBIA FOR DESERTIFIOATION OONTROL 855
Table 12-1 Fodder Value of Pods of Fl1dherbla albldt Compared with Peanut
Tops and Mature Native Grall
Total
yield
per ha
DinUjble protein
per kg per ha
dry weisM
Netp!M
per kg
dry weight
per ha
Faidberbla albjda
pods
Peanut foliage
Mature native
II'UI
2,500 kg '10 g
1,000 kg 60 g
.,000 kg 10 g
1,.0&8 Keal 1,820 Meal
'126 Kcal 2,268 Meal
S'18 Keal 1,500 Meal
Sourc..: Cbarreau and Nlcou (19'11)i Boudet and RiYire (196'1).
to 100 percent were found in the nitrogen, available phosphorus, and
exchangeable calcium content of the soil (Jung, 1967).
Studies by Dougain (1960) in Niger indicate that on a 10-cm
depth basis, which represents about 1,500 tons of soil per hectare,
the nutrient increases due to the presence of Faidher6ia al6ida were
equivalent to the following amounts offertilizer amendments per year:
300 kg nitrogen, 31 kg phosphorus as P 2 0 5 and 24 kg magnesium.
The tree also served as a windbreak, which protects crops and native
vegetation from mechanical damage and excessive transpiration
(Dancette, 1968).
Charreau and Vidal (1965) calculated that under Faidher6ia
al6ida trees in Senegal, millet production was 2.5 times that of crops
grown in the open, and protein content of the grain was up to
4 times greater. Dancette and Poulain (1968) demonstrated that
peanut production can be 36.7 percent greater under the influence of
Faidher6ia al6ida.
The nutritional benefit of Faidher6ia al6ida to crops grown beneath
the canopy is consistent with the "islands of fertility" concept
described by Garcia-Moya and McKell (1970) for shrubs and trees
in semiarid lands. Woody perennials extract nutrients from deeper
layers of the soil profile and deposit them at the surface in litter
(Charley, 1972; Fireman and Haywood, 1952; Rickard, 1965). These
plants also provide cover for animals and trap wind-borne debris.
Soil water retention may be as much as 43 percent higher under the
canopy of Faidher6ia al6ida (Charreau and Vidal, 1965). A more
favorable moisture and temperature environment will promote microbial
decomposition and nutrient release. Since Faidher6ia is a