mededelingen der zittingen bulletin des seances - Royal Academy ...

— 256 —
Residential plot ............................................................................................................ 0.10 ha
— Banana and associated crops ...................................................................................... 0.10 ha
— Rotation crops ............................................................................................................. 0.20 ha
Season A : cassava : 0.05 ha, beans : 0.125 ha, sweet potatoes : 0.025 ha ;
Season B : cassava : 0.05 ha, beans : 0.025 ha, maize : 0.1 ha ; sweet potatoes :
0.025 ha ;
— Fodder crops ................................................................................................................. 0.10 ha
— Industrial crops ............................................................................................................ 0.20 ha
— Forest ............................................................................................................................. 0.10 ha
— Anti-erosive hedges (10 %) ....................................................................................... 0.10 ha
T otal...................................................................................................................................... 0.90 ha
Valley soils per farm : 0.02 ha, of which 0.015 ha cultivable.
The expected yields of the different crops are listed in table 6. The reference
yields obtained by fertilizer experiments on the best soils are still below the
potential yields simulated from climatic data (Sys 1991). The results of the
calculation of the energetic balances are summarized in table 7.
Crop
Table 6
Estimated crop yields under intensive farming in the Butembo test area
Reference
yield
(kg/ha)
Consumable yield (kg/ha)
S l.l (86) S l,2 (80) S2 (52) Valley soils
Banana 25,000 19,350 18,000 11,700 _
Cocoyam 20,000 15,480 14,400 9,360 —
Cassava 22,000 17,028 15,840 10,296 —
Sweet potatoes 20,000 15,480 14,400 9,360 —
Beans 3,200 2,437 2,264 1,458 3,200
Maize 4,000 3,066 2,850 1,842 4,000
Table 7
N um ber of food portions of 2,220 Kcal produced per km 2 under intensive farm ing conditions
in the Butem bo test area
Suitability
class
Cultivable
surface area *
(ha)
Farm
size
(ha)
Number
of farms
Daily energetic
value of the
farm
(Kcalories)
Daily energetic
value of the
suitability class
(Kcalories)
Number of
food portions
of 2,220 Kcal
S l.l 30.91 0.9 34.3 14,944 512,579 231
S I,2 23.12 0.9 25.6 13,954 357,222 161
S2 4.63 0.9 5.1 9,248 47,164 21
Total/ mean 58.66 0.9 65.0 14,107 916,965 413
* The valley soils are excluded.