Promoting Cassava as an Industrial Crop in Ghana: Effects on Soil Fertility and Farming System Sustainability
Table 4
Estimated costs of production, gross revenue and returns on investment of (a) various crop sequences (b) maize grown after the sequences with N application to the maize and (c) maize grown after the sequences without N application to the maize.
Crop sequence
Economic yield (kg ha−1)
Total revenue (US$)
Cost of production (US$)
Total cost
Net revenue
Return on investment
Land
Input
Labour
(a) Crops in the sequence
1Cassava
31,000
2545.1
41.7
41.7
635.0
718.4
1826.7
254
2Pigeonpea
1,870
623.3
41.7
8.3
221.5
271.5
351.8
130
3Mucuna-maize-mucuna
2,016
365.1
41.7
41.7
247.4
330.8
34.3
10
4Cowpea-maize-cowpea
2,536 *(1,230)
1079.0
41.7
106,1
475.1
622.9
456.1
73
5Maize-maize-maize
3,287
595.2
41.7
36.1
386.1
463.8
456.1
28
6Speargrass fallow
0
0
41.7
0
0
41.7
−41.7
−100
(b) Maize after crop sequence with N application
CS 1
2,738
495.9
13.9
104.2
190.2
308.3
187.6
61
CS 2
2,974
538.5
13.9
104.2
196.5
314.6
223.9
71
CS 3
4,194
759.4
13.9
104.2
245.9
364.0
395.4
108
CS 4
2,331
422.1
13.9
104.2
177.0
295.1
127.0
43
CS 5
2,126
385.0
13.9
104.2
175.4
293.5
91.4
31
CS 6
2,848
515.7
13.9
104.2
224.4
342.5
173.3
51
(c) Maize after crop sequence without N application
CS 1
3,000
543.2
13.9
13.9
175.6
203.4
339.8
167
CS 2
2,423
438.8
13.9
13.9
165.5
193.3
245.5
127
CS 3
2,961
537.7
13.9
13.9
209.7
237.5
300.2
126
CS 4
1,772
302.8
13.9
13.9
155.2
183.0
119.8
66
CS 5
1,380
249.9
13.9
13.9
153.0
180.7
69.1
38
CS 6
1,048
189.8
13.9
13.9
173.7
200.9
−11.1
−6
1US$82.1 t−1. 2US$ 333.3 t−1. 3US$ 337.5 t−1 for cowpea and US$ 181.1 t−1 for maize.
*Yield of maize. CS 1: cassava; CS 2: pigeonpea; CS 3: Mucuna-maize-Mucuna; CS 4: cowpea-maize-cowpea; CS 5: maize-maize-maize; CS 6: speargrass fallow (source: [14]).
