Evaluating internal phosphorus requirement of rapeseed, chickpea, lentil, and wheat by seed analysis

Abstract

Foliar tissue in contrast to seed is considered a superior plant part for determining the nutrient‐element status of crops and soils. This study tested that generalization for oilseed, legume, and cereal crops. Internal phosphorus (P) requirements were estimated in pot culture experiments using a P deficient alkaline calcareous soil of Pakistan. The order of response (of grain yield) to P fertilization was rapeseed > wheat > lentil > chickpea. Phosphorus concentrations in whole shoots (≤ 30 cm) associated with 95% grain yields were: wheat and lentil, 0.28%; rapeseed, 0.27%; and chickpea, 0.18%. Critical P concentration in recently matured leaves were: chickpea, 0.39%; lentil, 0.33%; wheat, 0.30%; and rapeseed, 0.28%. Mature grains of crops, particularly of rape‐seed and chickpea, proved a good indicator tissue for evaluating P status of soils and plants. Phosphorus concentrations in seeds were associated with the P status of soil on which they grew. Internal P requirement in seeds were: rapeseed, 0.72%; chickpea, 0.37%; lentil, 0.26%; and wheat, 0.22%.