Crop simulation programs allow analyzing and exploring various tillage-rotation combinations and management. This study was conducted to apply and evaluate the DSSAT program under Egyptian conditions. The study was carried out to investigate the effect of tillage system, fertilizer rates and cereal/legume rotation on the crop yield and soil quality. The CERES-maize and CROPGRO-broad bean models were used to simulate the studied crop yield.
Field observations showed that, the effect of tillage systems during the summer season of 2013 did not differ significantly due to studied maize traits. Regarding, winter season of 2013/2014), the results showed that, CA tillage system increased significantly all studied broad bean traits as compared with the other tillage systems. Referring to, the summer season of 2014, CA system scored the significant high values for the studied maize traits.
As for the effect of studied NPK fertilizer levels, results indicated that, 100% of the recommended doses of NPK favored the values of the studied maize and broad bean traits significantly during summer 2013 and winter 2013/2014, as compared by 50% of the recommended dose of NPK fertilizers, while, there are no-significant difference between the two fertilizer levels for maize traits in the third season (summer, 2014).
With regard to, the first order interaction effect between the tested factors, results of the three trial seasons revealed that, growing maize or broad bean under the condition of conservation agriculture (CA) and fed by 100% or 50% of the recommended dose of NPK fertilizers scored the greatest values for most of maize studied traits and broad bean, and the differences between them did not reach the significant level. On contrast, the lowest value were resulted under the condition of Conventional agriculture (CT) and fed by the 50% of the recommended dose of NPK fertilizers.
The models that were used in this study also reflected this trend. The CERES-maize and CROPGRO-broad bean models greatly discovered stimulation for grain yield/fed., harvest index as affected by interaction effect between tillage systems and fertilizer rats, which their RMSE ranged between excellent and good, RMSE = (8.44, 12.19) and (11.70,16.79) and (0.15, 12.02) for summer 2013, winter 2013/2014 and summer 2014 seasons respectively, through (maize→ broad bean→ maize) crop sequence.