Assessment of Economics and Water Productivity of Four Crops Grown after Wet Season Rice under Differing Water Availability Conditions in Northeast Thailand

抄録

The economic profitability and water use productivity of four crops grown after rice harvest were assessed in two sub-districts, Dong Klang (DK) with limited water availability for irrigation, and Tung Pra (TP) with greater water availability, in Kornsarn District, Chaiyapoom Province, Northeast Thailand. Three households growing dry season rice, soybean, chili and field corn were purposively selected for each crop in each area. Higher crop yields were found in TP than DK for dry season rice, soybean and field corn (5000 vs 5513 kg/ha, 1646 vs 1971 kg/ha, 3633 vs 4563 kg/ha, respectively), while chili yield was higher in DK (14917 vs. 9083 kg/ha). Fertilizer cost was the main cost for dry season rice in both areas (39-42% of total production cost), followed by labor (27-38%), but irrigation cost was higher in DK than TP (21% and 9%). Seed cost was the main cost for soybean production in DK (43%), but combined harvester was highest in TP (41%). Labor for fruit picking was the main cost for chili in both areas (80-81%), and fertilizer was the main cost for field corn (36-53%). Net returns in both areas followed a similar pattern, chili> dry season rice > soybean ≥ field corn (18,838>1,880>827>598 USD/ha in DK; 15,462>1,512>540≈ 585 in TP), with higher net returns in TP due to lower costs. The benefit-cost ratio was highest for dry season rice in both areas; 4.06 and 4.86 in DK and TP, respectively. However, water productivity on a yield basis was lowest for rice in both areas (0.68 and 0.75 kg/m³ in DK and TP, respectively), and highest for field corn (0.98 and 1.23 kg/m³ in DK and TP, respectively). Measures to reduce water use for rice, and reduce costs and improve market access of other crops could improve water productivity and farmer income.