An economic evaluation of selected soil and water management technologies for rainfed agriculture : a study case in the arid zones of Brazil

Abstract

Water harvesting techniques were used for increasing water availability for rainfed agriculture and for human consumption. The treatments involving soil and water management for cropping were as follows: (1) traditional; (2) microcatchment; (3) microcatchment plus fertilization with ordinary superphosphate (OSP); (4) microcatchment plus fertilization with manure; and (5) supplemental tank irrigation. A cistern with 50 m³ capacity was constructed to provide drinking water. The crop enterprises were cowpeas (Vigna unguiculata)/corn (Zea mays), and sorghum (Sorghum bicolor)/cactus (Opuntia spp.)/algaroba (Prosopis juliflora). Both were intercropped. The overall objectives of the study were: (1) to examine the impact of the application of water harvesting techniques together with crop management, with and 14 without fertilization on: farmer, (ii) profitability cropping, and (iii) labor benefit of a cistern based (i) financial position of the of each individual enterprise in utilization; (2) to estimate the on the costs of carrying water. All analysis were developed with the aid of Supercalc 4 spreadsheet software. Farm performance measures were: crop production; cash flows; income statements, net worth; cost and returns statements; and labor utilization. The impact of the household cistern was assessed through a benefit cost approach. From the results the following main conclusions were drawn: (1) microcatchment contributed marginally to increased yields; (2) microcatchment combined with OSP produced yield increases which were twice those of the traditional process; (3) tank irrigation with OSP quadrupled the traditional productivities; (4) the sorghum/cactus/algaroba enterprise presented a better cash position than cowpeas/ corn; (5) the farm can support the investments necessary for the application of water harvesting since it is financially liquid and solvent; (6) significant increase in net income was achieved when water harvesting was combined with fertilization for both enterprises; (7) the existing family labor potential on the farm is enough to supply the demand imposed by any one of the soil and water management treatment; (8) if opportunity cost of labor is involved in assessing the profitability of cropping, the most profitable soil and water management practice was tank irrigation; and (9) the construction of a cistern is an economical and feasible decision.