Residual phosphorus and zinc influence wheat productivity under rice–wheat cropping system

Continuous cropping of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) deplete soil fertility and crop productivity. One strategy to increase crop productivity under rice–wheat system is balanced application of crop nutrients. Field experiment was conducted to assess the impact of phosphorus (0, 40, 80, 120 kg P ha(−1)) and zinc (0, 5, 10, 15 kg Zn ha(−1)) on the productivity of rice genotypes (fine and coarse) and their residual effects on the grain yield (GY) and its components (YC) of the succeeding wheat crop under rice–wheat cropping system (RWCS) in North Western Pakistan during 2011–12 and 2012–13. After rice harvest in both years, wheat variety “Siren-2010” was grown on the same layout but no additional P, K and Zn was applied to wheat crop in each year. The GY and YC of wheat significantly increased in the treatments receiving the higher P levels (120 > 80 > 40 > 0 kg P ha(−1)) and Zn (15 > 10 > 5 > 0 kg Zn ha(−1)) in the previous rice crop. The residual soil P and Zn contents after rice harvest, GY and YC of wheat increased significantly under low yielding fine genotype (B-385) as compared to the high yielding coarse genotypes (F-Malakand and Pukhraj). The residual soil P and Zn, GY and of wheat increased significantly in the second year as compared with the first year of experiment. These results confirmed strong carry over effects of both P and Zn applied to the previous rice crop on the subsequent wheat crop under RWCS.