Impact of Conjunctive Nutrient Management Practices on Soil Quality Indicators and Soil Quality Indices under Maize (Zea mays)-Wheat (Triticum aestivum) Cropping System in Hill and Mountainous Inceptisol Soils of Northern India

Abstract

A field experiment was conducted in the rainfed Inceptisol soils of Rakh Dhiansar in Kandi areas of Western Himalayas of South Kashmir and Kumaon from 2001 to 2005. The main focus of the present study was to quantify the impact of conjunctive nutrient management practices on soil quality parameters, to identify the key indicators of soil quality using data redundancy technique and to compute integrated soil quality indices (SQIs) and relative soil quality indices (RSQIs) as influenced by the conjunctive nutrient management treatments in hill and mountainous Inceptisol soils in Northern India under maize-wheat system. Out of the total 10 treatments, five treatments viz., T1: control, T2: FYM @ 10 t ha−1 + 20 kg N ha−1, T3: FYM @ 10 t ha−1 + 30 kg N ha−1, T4: FYM @ 10 t ha−1 + 40 kg N ha−1 and T5: green manuring with sunhemp + 20 kg N ha−1 were selected for the soil quality assessment studies. The nutrient management treatments significantly influenced the SQIs which varied between 3.69 to 5.66 across the management treatments, while the RSQIs varied between 0.63 to 0.96. Of all the nutrient management treatments, the application of FYM @ 10 t ha−1 + 40 kg N ha−1 maintained significantly highest SQI of 5.66, which was at par with the application of FYM @ 10 t ha−1 + 30 kg N ha−1 and green manuring with sunhemp + 20 kg N ha−1 both of which maintained SQI of 5.40. Irrespective of their statistical significance, the relative order of performance of the nutrient management treatments in maintaining the soil quality indices was: T4: FYM @ 10 t ha−1 + 40 kg N ha−1 (5.66) > T5: Green manuring with sunhemp + 20 kg N ha−1 (5.44) > T3: FYM @ 10 t ha−1 + 30 kg N ha−1 (5.40) > T2: FYM @ 10 t ha−1 + 20 kg N ha−1 (5.16) > T1: control (3.69). The percent contributions of each of these key indicators towards SQIs were also computed. It was observed that almost all the key indicators contributed more or less equally towards the SQIs except available N and available Fe, which contributed to a minimum extent of 2.27% and 1.90%, respectively. The percent contribution of the other key indicators was as follows: organic carbon (13.8%), available P (13.4%), available K (14.5%), available Zn (12.6%), microbial biomass carbon (13.7%), bulk density (15.2%) and mean weight diameter (11.6%).