Effect of potassium and zinc fertilizer on crop yield, nutrient uptake and distribution of potassium and zinc fractions in Typic Ustipsamment

A field experiment was conducted to study the effect of potassium and zinc fertilizer on status and content of potassium and zinc fractions and their effect on crop yield, nutrient uptake and nutrient availability in the soil. Significant increase in grain yield, straw yield, K uptake, and different K fractions in the soil (exchangeable K, water soluble K, Morgan's extractable K, lattice K and total K in the soil) were recorded with increase in K levels from 0 to 60 kg/ha. Zinc fertilization in wheat also significantly increased crop yield and Zn uptake but interaction between K and Zn was not found to be significant in respect of yield, uptake, and various K and Zn fractions. Water-soluble K showed significant and positive correlation with exchangeable K (r= 0.928), Morgan's extractable K (r= 0.983) and lattice K (r= 0.969), indicating rapid equilibrium establishment between these forms. Step wise regression analysis using different pools of K revealed the importance of water soluble K and lattice K influencing crop yield, K uptake by wheat. Similarly, application of 9 kg Zn/ha increased the Zn fractions present in soil and cm-relation data indicated that these fractions are in a state of dynamic equilibrium with each other. In the present study, DTPA-Zn accounted for 65% and 70% of the variation in grain yield and Zn uptake by wheat, indicating that DTPA-Zn was efficient in providing Zn nutrition to wheat.