Nain, A.S.Sonam2019-07-182019-07-182019-06http://krishikosh.egranth.ac.in/handle/1/5810115408The current focus of Indian agriculture is to maximizing the production by optimizing the limited resources so that production system could be sustained over a longer period of time. Considering this fact, the present study was conducted to optimize input resources in chickpea by calibrating the crop simulation model on experimental data set under Tarai region of Uttarakhand. The experiment was laid during rabi 2017-18 at Norman E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar with three dates of sowing and two irrigation levels. CROPGRO-Chickpea model was used as a tool to achieve the objective and was calibrated using rabi 2017-18 experimental field data. The important finding of the study is that sowing on 29th November resulted into highest number of root nodules per plant as well as maximum dry weight of nodules per plant. The relative increase in number of root nodules per plant was found to have negative correlation with temperature (R²=0.36) and positive correlation with RH (R²=0.34). Similarly, relative gain in dry weight of root nodules per plant possessed negative correlation with temperature (R²=0.32) and positive correlation with relative humidity (R²=0.21). The model could capture all phenological stages reasonably. The growth and yield parameters of chickpea could also be simulated very well with RMSE less than10%. Under non-limiting condition of other resources, the model identified first fortnight of November sowing date to produce maximum yield. Nitrogen and irrigation were optimized by considering four rabi seasons. Varying number of doses of nitrogen (18kg/dose) from one to three caused an increase in yield of chickpea but the relative increase per dose followed a decreasing trend. Another important finding was that if sowing date is delayed, nutrient use efficiency is also declined, therefore excess amount of nitrogen application results into wastages of resources. In case of failure of winter rains, model suggested two irrigation (one at pre-flowering stage and other at pod development stage) for crops sown up to first fortnight of December and three irrigation (at early vegetative stage, pre-flowering stage and pod development stage) for crops sown during 2nd fortnight of December. However, if limited water is available, one irrigation during the initiation of pod development stage was simulated to be optimum by the model. If winter rain occurs, only one irrigation during sensitive stage of chickpea facing stress should be applied.ennullThesis