Influence of tillage, water regimes and integrated nitrogen management practices on soil quality indices in rice (Oryza sativaL.) in the Indo-Gangetic plains

Abstract

A field experiment was conducted on sandy clay-loam soil at New Delhi, during 2004 and to investigate the effect of irrigation regimes, namely, continuous submergence, one-day drainage, and three-day drainage, and integrated nutrient management practices on the soil biological health parameters under rice cultivation. The non-puddled soils showed significantly high soil respiration (17.32%) and soil microbial biomass carbon (45.51%) activity than the puddled soils. However, the soil dehydrogenase enzyme activity was 65.26% higher under puddled soils than the nonpuddled. Among the integrated nitrogen management, substitution of 25% recommended dose of nitrogen (RDN) as biofertilizer resulted in highest (560.02 mg TPF g 71 soil 24 h 71 ) enzyme dehydrogenase (DH) activity and application of entire RDN as organics supported the highest soil microbial biomass carbon (218.29 mg g 71 soil) and respiration activity (56.67 mg CO 2 [100 g 71 soil 24 h 71 ). In comparison with other organic N inputs, substitution of sewage-sludge for 25% RDN resulted in the least soil respiration (47.67 mg CO 2 100 g 71 soil 24 h 71 ), low DH enzyme activity (313.37 mg TPF g 71 soil 24 h 71 ) and soil microbial biomass carbon content (183.85 mg g 71 soil). The present study suggests that inorganic, organic and bio-fertilizer combinations significantly improved soil health parameters.

Conservation tillage and optimal water supply enhance microbial enzyme (glucosidase, urease and phosphatase) activities in fields under wheat cultivation during various nitrogen management practices

“…The combination of inorganic and organic N forms improved the rhizospheric enzymatic properties in conservation tillage and water regimes. These observations may be attributed to the stratification of soil organic matter in the upper (0-15 cm) layer of the soil in the conservation tillage system in contrast to conventional tillage where an even distribution of organic matter exists throughout the soil profile, so more organic C exists in upper layer, which accounts for the higher microbial population and respiration rate in comparison with the alternate method of tillage where there is an even distribution of crop residues (Singh G et al 2009). …”

“…The recommended dose of N in this region for wheat is 12 g m 72 (Singh G et al 2009). Wheat cultivar (cv.)…”

“…Soil enzymes are considered to be a major index for soil microbial activity and soil organic carbon status (Singh G et al 2009). These include aand b-glucosidase and urease (Bandick and Dick 1999).…”

“…b-Glucosidase has been suggested as an assay that reflects soil management effects and has microbial significance because of its role in the carbon cycle. It has been reported that urease activity is very crucial for the soil N metabolism and is found to be positively affected by the use of organic manure compared with chemical N fertilizers (Mikanova et al 2009;Singh G et al 2009). Phosphorus is an essential, but limiting macronutrient that plays a critical role in plant metabolism and development.…”

Conservation tillage, optimal water and organic nutrient supply enhance soil microbial activities during wheat (Triticum Aestivum L.) cultivation

“…Tillage affects the physical, chemical, and biological properties of the soil (34). A proper tillage can alleviate soilrelated constraints whereas an improper tillage leads to a deterioration in soil structure.…”