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to the high P-fixation capacity of these soils an annual heavy application
of P is required.
In order to assess the supporting capacity of these soils, we have used the
following farm structure :
Residential plot .................................................................................................................. 0.25 ha
Rotation crops ......................................... ......................................................................... 0.30 ha
Green manure/fodder crop ............................................................................................. 0.20 ha
Industrial crop ................................................................................................................... 0.15 ha
Forest ................................................................................................................................... 0.10 ha
Anti-erosion hedges........................................................................................................... 0.10 ha
T otal...................................................................................................................................... 1.10 ha
The residential plot will be used alternatively for maize, beans and vegetables.
The crop rotation includes the following crop pattern :
Season A
White potatoes................................................................................................................... 0.10 ha
B eans..................................................................................................................................... 0.20 ha
Season B
W heat.................................................................................................................................... 0.10 ha
Sorghum .............................................................................................................................. 0.20 ha
The expected consumable crop yields are given in table 16, and the results
of the calculation of the energetic balances are summarized in table 17.
Table 16
Estim ated crop yields under intensive farming in the Masisi test area
Crop Reference
yield (kg/ha)
Consumable yield (kg/ha)
S l ,l (100) S l,2 (80)
W hite potatoes 18,000 16,830 12,870
Beans 2,600 2,300 1,836
M ai/e 2,400 2,133 1,701
Sorghum 2,600 2,322 1,854
W heat 3,000 2,624 2,084
3.3. T h e S o u t h K i v u t e s t a r e a
The South Kivu test area is located NW of Bukavu, on the western slope
of the Kivu mountain range just north of the parallel 2° 30’ S. The geological
substratum is characterized by Paleozoic formations of the Urundi and Ruzizi
systems, alternated by basalt flows and granite intrusions. The digitized soil
mapping units were regrouped in suitability classes (table 18).