Comparative assessment of soil fertility status of various agroecological regions under intensive cultivation in Northwest India.

Abstract

Assessment of soil fertility status at agroecological region scale can help draw sound nutrient management and cropping plans for sustainable agriculture. It can also forewarn about emerging issues especially in regions under long-term intensive cropping. To meet this objective, 500 surface soil (0-15cm) samples were collected from the five agroecological regions of Punjab state (India). The regions were Sub-mountainous Siwalik Hills (SSH), Northeastern Undulating (NEU), Piedmont and Alluvial Plain (PAP), Central Alluvial Plain (CAP), and Southwestern Alluvial Plain (SWAP) running from northeast Punjab to southwest Punjab in that order. Highest soil organic carbon (SOC) content (mean, 0.77%) was observed in the SSH region, despite it being dominated by coarse-textured soils (mean sand content 74.2%). The Piedmont and Alluvial Plain region showed the highest mean available potassium (K) content (mean 173.2kgha-1 with 76-865kgha-1 range) which can be attributed to K-rich mineralogy and higher K fertilizer use in the region. In contrast, relatively lower K levels in the Central Alluvial Plain region warned about K mining under predominant rice-wheat system. Higher electrical conductivity (EC, mean 0.95dSm-1) values in the SWAP region and in some areas in the CAP region hinted at the risk of land degradation due to salinity. The study revealed impending micronutrient deficiencies in certain areas. Overall, the investigations suggested dominant influence of climate and parent material on fertility status with agronomic interventions mainly affecting distribution of P, K, and Zn only.