Long-Term Effect of Different Cropping Systems on Soil Physico-chemical Properties of Soil: Environmental Implications and Sustainability

Abstract

Rice (Oryza sativa L.)-wheat (Triticum aestivum L.) a dominant cropping system in Punjab Region, Northwestern India, overtime is believed to have negative effect on the soil and water quality. The present study was conducted in an ongoing long-term experiment at the research farm of the School of Organic Farming, Punjab Agricultural University, Ludhiana, to compare the effect of different cropping systems on soil physico-chemical properties. Ten treatments (cropping systems) were laid in a Randomized Complete Block Design (RCBD). The treatments were rice-wheat (CS1), maize-wheat (CS2), basmati rice-wheat-cowpea green manure (CS3), maize-mustard-cowpea green manure (CS4), maize-potato-spring groundnut (CS5), maize-peas-spring groundnut (CS6), maize+ cowpea (fodder)-maize fodder-oats fodder-sathi maize fodder (CS7), sorghum multicut fodder-barseem fodder (CS8), maize (cobs/fodder)-potato-onion (CS9), and baby corn-potato-okra (CS10). Soil samples were collected from four soil depths (0-7.5, 7.5-15, 15-22.5, and 22.5-30 cm) under each cropping system and analyzed for particles size, soil pH, EC, soil organic carbon, aggregate associated carbon, bulk density, porosity, water stable aggregates, MWD, and penetration resistance. Significantly lower soil pH was reported in CS4 and CS8 compared to other cropping systems. Soil EC was significantly higher in CS5 and CS10 while lowest in CS4. Soil organic carbon (SOC), aggregate-associated carbon (AAC), and mean weight diameter (MWD) were significantly higher in CS7 and CS4. Soil bulk density (BD) and penetration resistance (PR) were significantly higher in CS1 and lowest in CS4. SOC was 19% higher in CS7 and BD was 16% lower in CS4 compared to CS1. Soil porosity and water-stable aggregates (WSA) were also found significantly higher in CS4 and CS7 whereas lowest in CS1. The increase in soil depths significantly increased the soil pH, BD and PR, whereas decreased the soil EC, SOC, AAC, porosity, MWD, and WSA. The cropping systems (CS4, CS7, CS8, CS6, CS5, CS3) with green manure/legume/fodder crops in rotation resulted in better physico-chemical properties through the addition of organic matter to the soil compared to cereal-cereal rotations.