Crop Yields and Nutrient Uptake in a Cropping Sequence under Resource Constraints

In a three year study on the production potential of maize-wheat-green gram rotation and nutrient removal under constraints of fertilizers and irrigation, it was seen that a reduction in fertilizer dose from 100% of the recommended amounts of N and P to 75 and 50% levels resulted in an overall decrease of 13 and 26% in grain yield, respectively. When the frequency of irrigation was reduced from 5 or 6 to 3 or 4 (total volume of water being the same in either case) it did not cause much variation in the yield of wheat. Similarly, the reduction in number of irrigation from 8 or 10 to 4 or 5 did not affect grain production in green gram. Nitrogen and phosphorus uptake by the crops decreased with curtailment in fertilizer dose while such effects due to variations in irrigation was found to be marginal.