Author : Rusnadi Padjung

Summary : Three modules of Macros model-L1D, L2C, and L2SS- were used to simulate the growth and yield of two rice varieties, soybean, corn, cowpea, and peanut and determine the potential productivity of such crops at different planting dates under rainfed condition at Maros, South Sulawesi, Indonesia. The risk of different cropping patterns were also quantified and the most feasible cropping pattern for rainfed riceland area at Maros were also determined. Hydraulic properties of the soil based on a soil survey report and direct measurement of soil samples done at IRRI as well as daily historic climate data of Maros for 15 years were used to run the model. The simulation showed that it was less feasible to grow soybean, corn, and cowpea as pre-rice crops. Mean simulated yield of these crops at different planting dates had ranges of 0-1.22, 0-0.11, and 1.26-4.59 ton/ha, respectively. Double-cropped rice was feasible, but the second crop was prone to tungro disease. Soybean, peanut, and cowpea was possibly grown after rice. To accomodate these crops, rice was transplanted between 16 December and 16 January so that the upland crops were sown on 1 April, 1 May, and 16 May for soybean, cowpea, and peanut, respectively. Simulated yields at this planting date were 5.84-6.76 ton/ha for rice and 2.51, 0.66, and 2.02 ton/ha for soybean, cowpea, and peanut, respectively.