tokens: By conjunctively simulating the effects of different influencing factors ( climate , soil , management , crop characteristics ) on crop production , models allow to ( 1 ) better understand the mechanism behind improved water use efficiency , to ( 2 ) schedule the necessary irrigation applications during the drought sensitive crop growth stages , considering the possible variability in climate , to ( 3 ) test DI strategies of specific crops in new regions , and to ( 4 ) investigate the effects of future climate scenarios or scenarios of altered management practices on crop production .