SOIL QUALITY INDEXING OF AN ACID ALFISOL UNDER MAIZE WHEAT CROPPING SYSTEM AS INFLUENCED BY CONTINUOUS USE OF CHEMICAL FERTILIZERS AND SOIL AMENDMENTS

Abstract

newlineABSTRACT newlineKeeping in view the importance of soil quality in maize-wheat cropping system, the present investigation was undertaken with the objective of identifying physical, chemical and biological indicators of soil quality using data collected from a long-term fertilizer experiment being conducted since 1972 on maize-wheat cropping system at experimental farm of College of Agriculture CSK HPKV, Palampur. The experiment was laid out in a randomized block design with eleven treatments under long-term fertilizer experiment [i.e., control, 100% N, 100% NP, 100% NPK, 100%NPK + FYM, 100% NPK + Lime, 100% NPK + HW, 100% NPK + Zn, 100% NPK (-S), 50% NPK and 150% NPK] replicated three times. Soil samples from surface (0 0.15 m) and subsurface (0.15 0.30 m) were collected after harvest of 39th wheat crop during 2010 11 and were analyzed for physical, chemical and biological properties. On the basis of the long-term yield data, sustainable yield index (SYI) was calculated. Highest (0.854) and lowest (-0.116) overall SYI values were found in 100 per cent NPK + FYM and 100 per cent N treatments, respectively. As per multivariate statistical analysis techniques, saturated hydraulic conductivity, soil pH, labile carbon, available P and K, DTPA extractable Zn and nitrogen mineralization were found to be the most important MDS indicators in this study. Multiple regressions evaluated the efficacy of MDS taking SYI as goal (r2 = 0.98 and 0.95 for surface and sub-surface soil samples, respectively). Each MDS variable was transformed into score. The soil quality index (SQI) was calculated by using weighting factors derived from principal component analysis (PCA) for each scored MDS variable. The highest SQI values (2.848 and 2.811 for surface and sub-surface soil samples, respectively) were found in 100 per cent NPK + FYM treatment followed by 100 per cent NPK + Lime (1.673 for surface soil and 1.793 for sub-surface soil) and 100 per cent N treatment being the lowest (0.112 and 0.263, respectively for surface and sub-surface soils). It was concluded that the balanced fertilization along with manures (100% NPK + FYM) improved the soil aggradation process as well as biological activity of soil and maintained soil quality and sustainability of productivity. newline