Effect of continuous application of fertilizers on soil properties and crop yield
1998
Subhani, A. | Rashid, M.Z. | Ahmad, S. (Soil and Water Testing Lab., Multan (Pakistan)) | Akhtar, S.
Three nitrogen (N) sources viz.; ammonium sulphate, ammonium nitrate, urea and one Phosphate (P) source i.e. single superphosphate (SSP) were tried for 17 years @ 150-200 kg N or P2O5 ha-1 singly or in combination to observe their effects on soil properties and wheat yield. Application of N or P alone caused a decrease in crop yield during the last few years but no consistent differences were recorded amongst the three N sources. The maximum yield during each year was obtained with combined application of N and P. All fertilizer treatments reduced soil pH and the greatest reduction in pH was caused by ammonium sulphate alone. Whereas ECe, total soil N and CEC were increased by fertilizer treatments. Phosphorus alone or in combination with N increased the soil available P while N alone decreased it. All fertilizers decreased the degree of dispersion and this decrease was relatively more pronounced with P alone or in combination with N while the hydraulic conductivity was increased by all the fertilizer treatments except urea.
显示更多 [+] 显示较少 [-]