Long-term simulation of yield per unit area and time in crop sequences differing in intensification.

CAVIGLIA, O.P.AND SADRAS, V.O.

Brisbane, Australia

Congreso; 4th International Crop Science Congress.; 2004

Wheat-soybean double crop is the main element of cropping intensification in the southeastern pampas of Argentina. The long-term impact of including double cropping in the entire crop sequence is unknown. Locally calibrated DSSAT models and climatic records (30 years) were used to estimate the yield of crop sequences combining wheat, soybean and maize. Annual glucose yield averaged between 5.9 and 8.7 t ha-1. Intensification, quantified with the intensification sequence index (ISI; #crop per year) increased the average annual yield and its coefficient of variation. Annual glucose yield increased from 10 to 28% with increasing intensification sequence index (ISI = # crops per year). In parallel with the increase in yield, greater ISI resulted in higher coefficients of variation. Broader comparisons indicated both wheat-maize and double cropped wheat/soybean-maize could lead to highest annual yield. Lowest yields were obtained with wheat-soybean and double cropped wheat/soybean-soybean. Simulations highlighted the contributions of wheat to stability and of maize to productivity of cropping systems in the southern Pampas.