How we used APSIM to simulate conservation agriculture practices in the rice-wheat system of the Eastern Gangetic Plains

Examples of how to simulate performance conservation agriculture (CA) and conventional tillage (CT) practices using cropping systems models are rare in the literature, from Eastern Gangetic Plains (EGP). Here we report a comprehensive evaluation capacity APSIM for simulating CA CT under diverse range (CT vs zero (ZT)), crop establishment options (puddled transplanted rice unpuddled rice), residue, N rates, irrigation two sites EGP that differed soil type, water table dynamics, agro-climatic conditions. We followed robust procedure model parameterisation, calibration, validation, then undertook statistical analyses evaluate performance. have demonstrated when different values key input parameters employed (i.e. change properties (Ks, BD)), rooting (xf- root hospitality, kl- extraction efficiency) microorganism activity (F biom - fraction organic matter present as microbial biomass F inert matter), performed well performances management across environments EGP. Model was markedly better full-N than zero-N, but both still considered acceptable. In addition well-watered fertilised treatments, able capture an observed failure rainfed accurately, illustrating ability response wide stress environments. As by criteria, effect system, irrigation, tillage, N-application rate within bounds experimental uncertainty, hence is now deemed suitable tool scenario around relevant practices. • calibrated validated CT, Modifying several BD, xf, kl, Fbiom, Finert) generic factors captures treatments APSIM's zero-N gives confidence indigenous supply being accurately simulated. successfully captured rice. simulated NO 3 -N dynamics error.