Models for crop parameters due to normal load of tractor and number of passes.

Multiple passage of power machinery system particularly heavy machines with high wheel loads creates sub-soil compaction which results into increasing in soil bulk density & penetration resistance and reduction in crop germination, growth as well as yield. This study was conducted to determine the wheat crop growth and yield models could be developed to predict growth as well as yield of crop considering normal load and number of passes of tractor. A 36-plot experiment consisting of 12 treatments with three replications were set up using a randomized block design in a uniform field of Division of Agricultural Engineering, IARI, New Delhi. Prediction models were developed between compaction parameters (normal loads and number of passes) and crop parameters like (a) plant height, (b) number of plants per meter, and (c) yield. Further, another relationship between crop yield and sub-soil bulk density and penetration resistance were established and their sensitivity analysis was done. The best fit model for plant height and number of plants per meter row was quadratic. However, the best fit models between yield vs soil bulk density and yield vs penetration resistance for critical layer and whole soil were exponential and quadratic, respectively. The developed model is not more sensitive for number of plants per meter row and yield vs soil bulk density. However, model was more sensitive to plant height model as well as yield vs soil penetration resistance. [ABSTRACT FROM AUTHOR]