Nutrient Utilization Indices of NPK and Drought Management in Groundnut under Sandy Soil Conditions

ABSTRACT

In arid zones, farmers are obligated to reduce water amounts used in irrigating their lands. Consequently, reduction in final yields is realized. Thus, dealing with such a case became a decisive act. We tried to investigate the acceptable degree of lowering irrigation water with sustaining the productivity of groundnut as a way for managing drought conditions. Therefore, in summer seasons of 2016 and 2017 at the Experimental Research and Production Station, National Research Centre, Egypt, field trials were conducted with growing groundnut plants under three irrigation levels, i.e., 50%, 75%, and 100% of crop evapotranspiration (ET_c), denoted as I₅₀, I₇₅, and I₁₀₀, respectively. N, P, and K contents in seed and shoot and their yields in addition to harvest and partitioning indices were estimated. In spite of irrigating groundnut plants by normal water amounts, I₁₀₀, caused the maximum weight of seed biomass yield ha?1 and seed N and P contents, I75 was similar to I₁₀₀ for producing shoot biomass yield ha?1 and seed K content. Moreover, N and P yields (for shoots and seeds) and k yield (for seeds) showed the maximum values with I₁₀₀. Differences in all nutrient harvest indices (NHI, PHI, and KHI) between I₁₀₀ and I75 were not significant. Furthermore, I75 statistically leveled with I₁₀₀ in nutrient partitioning indices, viz., NPI, PPI, and KPI. In conclusion, groundnut straw residues produced by 25% less water supply than normal may share in managing drought stress by releasing nutrients and saving irrigation water in arid areas.