Long-Term Manuring and Fertilization Effects on Soil Physical Properties after Forty Two Cycles under Rice-Wheat System in North Indian Mollisols

Abstract

An investigation was carried out at Norman E. Borlaug Crop Research Centre of G. B. Pant Univ. Agric. & Tech. Pantnagar, U. S. Nagar, Uttarakhand, India in order to study the influence of long-term applications of fertilizers and manures on different soil physical properties after forty two cycles in silty clay loam textured Typic Haplustept under rice-wheat cropping sequence during 2012-13. The field was laid out in a randomized block design comprising of ten treatments. Various soil physical properties were measured in surface and sub-surface soil after harvest of rice and wheat crops after 42 cycles and it was found that in 0-60 cm soil layers, the bulk density was significantly lower in 100% NPK + FYM over other treatments. The balanced application of NPK decreased the bulk density in all the soil depths. Irrespective of soil depths, the control plot invariably showed higher bulk density. The soil receiving 100% NPK fertilizers with FYM recorded significantly higher hydraulic conductivity, water holding capacity and mean weight diameter in soils of all four depths, respectively as compared to control and all other fertilizer treatments. Application of P in combination with N significantly increased the hydraulic conductivity in comparison to where N was applied alone. Mean weight diameter increased with increasing fertilizer dose from sub optimal 50% NPK to 100% NPK optimal dose of NPK. The present investigation clearly points out the significance of balanced use of nutrients including FYM in rice-wheat cropping system for improving the various physical soil properties over a long period.