Application of SOYGRO in Argentina

Abstract

In Argentina, soybean (Glycine max (L.) Merr.) is an important crop. Eighty percent of soybean oil and 95% of soymeal are exported, which represents 50% of the country’s agricultural exported product. In the last years, the sowing area with soybean crop has increased, reaching more than 6 10⁶ ha in 1995. This area is planted with different maturity groups in dryland conditions with an average yield of 2.5 ton ha⁻¹. Soybean is usually planted as the first crop at the beginning of November or as second crop after wheat from the beginning of December until late December. Although the National Institute for Agricultural Research (INTA) has been developing several maturity group strips according to latitude, the farmers use different maturity groups with overlapping criteria. During the last three years, INTA has been calibrating and validating the Soybean Model included in DSSAT V2.I and V3.0 (Decision Support System for Agricultural Transfer). Specific objectives were: (i) to calibrate the soybean SOYGRO model for cultivars used in Argentina, (ii) to predict soybean yield for Argentina during l992–93 and 1993–94 growing seasons and (iii) to determine research needed to improve the ability of the model to predict soybean yields under weather and soil conditions of Argentina. The production was calculated using satellite information in order to determine the surface cultivated with soybean, and the SOYGRO model to calculate the yield according to planting date, soil and climate condition in the main soybean region. According to the Government Department of Agriculture, soybean production was 11.05 10⁶ton, and 11.31 10⁶ton for crop seasons 1992–93 and 1993–94 respectively. By using the SOYGRO model, the production was overestimated by about 5% for both years. The results suggest that the effect of low temperature during grainfilling might cause deviations in yield which cannot be simulated by the model. The results showed that SOYGRO could be used to predict the final yield of soybean in calculating the average yield in broad conditions of soil, climate and planting date.