Temporal and spatial variability of nutrient contribution towards productivity of hybrid rice and maize crops through omission plot technique in calcareous soils

n calcareous soils, field experiments were conducted at ۲۲ farmers’ field at different locations to evaluate the impact of omission of nutrient from fertilizer schedule towards nutrient contributions in hybrid rice and maize cropping system. Application of balanced dose of fertilizers yielded maximum in both hybrid as well as inbred crops. Omission of the nutrients reduced the rice equivalent yield (REY) over ample fertilization, and in general, N (۵۲.۵%) was most limiting nutrient followed by P (۱۹.۸%), K (۱۶.۲%), S (۱۱.۴%) and Zn (۱۰.۹). At permanent sites, decrease in yield was more pronounced in second and third year than the first year due to regular omission of the respective nutrients. The hybrid rice and maize yielded ۳۱.۸ and ۴۰.۰ percent more grain yield, respectively than the inbred crop with ample fertilization based on target yield. The yield potential and harvest index of hybrid crops was more than the inbred crops, so it accumulates more nutrients in its biomass than the inbred crops. Omission of nutrients also decreased the nutrient uptake over ample fertilized plot. Under hybrid rice-maize system, omission of N, P, K, S and Zn decreased the total uptake by ۶۱.۰, ۵۱.۵, ۴۱.۸, ۴۳.۰ and ۴۰.۷ percent, respectively over ample fertilized plot. Also, hybrid crop mines more nutrients than the inbred crops. The fertility was found to decline more in nutrient omission plots and unfertilized plots, while a build up was recorded in ample fertilized plot. The percent contribution of available nutrients to uptake by hybrid crops was more than the inbred crops. Thus, the study on nutrient omission helps a crop grower about the understanding of nutrient deficiency symptoms and application of nutrients especially secondary and micronutrients raised due to temporal and spatial variability in soils.

کلیدواژه ها:

Omission plot technique ، Nutrient contribution ، Calcareous soil.