Effect of zinc application methods on apparent utilization efficiency of zinc and potassium fertilizers under rice-wheat rotation.

Apparent utilization of zinc (Zn) and potassium (K) fertilizers was examined in rice (Oryza sativaL.)-wheat (Triticum aestivumL.) using combinations of no K; soil applied K levels and no Zn; soil and foliar applied Zn. Application of 33.2 kg K ha−1in rice and 24.9 kg K ha−1in wheat along with foliar spray of 2 kg Zn ha−1at 30 and 60 days gave the highest mean grain yields. Foliar application of zinc increased Zn concentration in flag leaves, grain, and straw of rice and wheat and K concentration in flag leaves of rice and straw of wheat significantly. Potassium application increased Zn concentration in rice grain and straw and K concentration in wheat straw significantly. Zinc and K increased the uptake of each other in grain; straw and total uptake by both crops significantly. Zinc fertilizer enhanced the utilization of soil K. Potassium fertilizer enhanced the utilization of applied Zn. [ABSTRACT FROM AUTHOR]