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phosphate (TSP) were applied in 25 cm bands. The cowpea variety IPEAN V-69 was planted in rows 60 cm apart. Plot size varied from 100-200 square meters. Land preparation and planting methods consisted of clearing the area by slash and burn, followed by manual land preparation and planting with sticks.
The project area is inhabited by subsistence farmers who clear land from primary forest (PF) or secondary forest (SF) and farm it up to three years before abandoning it as waste land (WL). Cowpea trials were established on 13 locations. Eight were replicated and five were not. Yield results, averaged. across replications where appropriate, and the environmental index for each location are shown in Table 1. Analysis of variance using the model (4) with R = 1 is shown in Table 2.
For the criterion Mg ha', the response of the four treatments to environment, using modified stability analysis, is shown in Figure 7. It is clear that amendments are needed to maximize per ha yield from these soils. In the poorer environments (El< 1.32) CM produces the best results, and in the better environments (El > 1.32) TSP is best.
The biophysical characteristics of the better and poorer environments closely follows the nature of the land being used. That is, the better environments (El> 1.32) are all land taken from PF and in first or second year of use and SF in first year of use. All other categories (PF3, SF2, SF3, WL) are in the poorer environments. For farmers whose evaluation criterion is to maximize Mg ha', the research domain can be divided into two recommendation domains. For farmers with PF, and PF2, the recommendation is to use TSP. Farmers in all other cases should use CM.
Figures 8,and: 9-show.the. MSA. resultaifor the, alternate, evaluation criterion of kg per dollar of cash cost (kg/$CC), a criterion usually of great importance to farmers in this area who have little cash to spend for agricultural inputs. Figure 8 shows that for the better environments (here El> 1.25, but covering the same soil situations) FP is by far the best practice of those tested. In the first or second year out of primary forest, none of the other tested treatments would be acceptable to farmers for whom cash is very scarce and therefore need to maximize kg/$CC. For any other soil situation, however, either TSP or CM could be recommended even if the farmers had to use scarce cash to purchase the amendments.
The use of Figure 9 narrows the choice somewhat in the poorer environments. CM
produces very stable results compared to TSP which could result in fewer kg/$CC than FP. This leads to the recommendation of CM as the best choice of those treatments tested in cases where farmers use, or are forced by circumstances to use fields more than one year out of secondary forest or two years out of primary forest.
FOCUS ON INDIVIDUAL FARMERS. FARMS. AND FIELDS IN COMMERCIAL AGRICULTURE
Farmers, themselves, continually fine-tune.their systems to the specific resource-and
infrastructure conditions in which the farm and family are found. In addition to the crop varieties mentioned earlier, a number of innovations in farm equipment originated with producers. Perhaps the agricultural machinery industry has been the sector most active in capturing the experience of farmers and putting this into commercial practices. Many of the current tillage, planting, and harvesting units have reached their present form through farmer modification of what was on the market, and then tested and adopted by industry for the next generation of commercial units. The ridge tillage planters and cultivators are currently going through this phase of farmer modification. A number of cropping system innovations likewise originated with farmers. Annual windbreaks have been proven usefulto reduce, transpiration in cropsbetween thewindbreaks, and perennial
(