Laboratory analysis was made on the soil samples collected (October 2013) from an on-going long-term field experiment (in progress since Kharif 2009-10) at Department of Soil Science, PAU, Ludhiana to investigate the effect of manure and chemical fertilizers in rice (Oryza sativa L.) - wheat (Triticum aestivum L.) system. The organic manure through bio gas slurry (BGS) @ 6 t ha-1 was incorporated along with nitrogen fertilizer (N @ 80 and 120 kg ha-1 ), phosphorus fertilizer (P @ 30 kg ha-1 ) and potassium fertilizer (K @ 30 kg ha-1 ) to the rice crop. The results of our study reported that the total Zn decreased with increase in soil depth, whereas the increased concentration of total Cu, Fe and Mn was observed at lower soil depths. Higher concentration of total Zn, Cu, Fe and Mn was also found in the treatments where organic manure (BGS) was added @ 6 t ha-1 along with N @ 80 kg ha-1 and K @ 30 kg ha-1 to the rice crop. The results of this study were of practical utility since application of manure and chemical fertilizers together increased total Zn, Cu, Fe and Mn in the surface soil whereas, their concentrations decreased with depth. | Long term effect of manure and fertilizers on depthwise distribution of total Zn, Cu, Fe and Mn under rice-wheat system
