NITROGEN MANAGEMENT UNDER CONSERVATION AGRICULTURE IN MAIZE (Zea mays L.)

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Date
2016
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DIVISION OF AGRONOMY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
The application of nitrogen in conventional way under residue retention in conservation agriculture attracts losses due to volatilization and immobilization that leads to lower crop yields and resource-use efficiency that gives more environmental footprints and decreases farm profitability. A field study was conducted on ‘Nitrogen management under conservation agriculture in maize (Zea mays L.)’ during kharif 2015 in an ongoing long-term experiment since 2012 at New Delhi. The soil of the experimental site was sandy loam in texture with neutral pH having low N, medium P and high K availability. The treatments consisted of two cropping systems: maize-mustard-mungbean (MMuMb) and maize-wheat-mungbean (MWMb); two residue management practices of with (WR) and without residue (WoR) and four N management practices of control, prilled urea (PU), sulphur coated urea (SCU) and neem coated urea (NCU) arranged in split-split plot design and replicated thrice. The growth parameters and yield attributes of maize were enhanced by the application of WR, MWMb and NCU. After water stress significant decrease in canopy temperature was recorded with WR (-3.39 0C) compared to WOR (-1.84 0C). Significantly superior yields viz., stover (10589 kg/ha) and grain yield (5786 kg/ha) under MWMb, cob (7548 kg/ha), stover (10489 kg/ha) and grain yield (5804 kg/ha) in residue management while, cobs (8382 kg/ha), stover (11989 kg/ha) and grain (6701 kg/ha) by application of NCU were recorded. However, SCU resulted in significantly higher HI (33.7%) than control (25.3%), but it was statistically at par with PU (33.2%) and NCU (32.8%) application in our study. The significant effect on the N, P, K, Fe, Zn and Cu concentration and uptake of maize grain and stover was recorded with residue, cropping system and N fertilization practices. The treatments of WR, MWMb and NCU recorded higher PFP, AE, ANR and PE of applied N along with enhancement in water productivity and its efficiency. These treatments recorded lower bulk density and penetration resistance in soil with enhancement of organic carbon at different depths. The increase in mineral N at various crop growth stages and other nutrients availability at harvest (Fe, Zn, Cu and K) was also found in WR, MWMb and NCU treatments. However, at 45 DAS significantly highest mineral N was recorded in PU where split application was done at 30 DAS. The microbial biomass carbon and enzymatic activities (dehydrogenase, floresein diacetate and ß Glucosidase) were also recorded significantly higher by WR at flowering and at harvest stage of the crop. Similarly, MWMb cropping system enhanced the net returns and BC ratio to the tune of 13.0 and 12.7 per cent, respectively over the MMMb but no significant effect or residue was found on these parameters. Among the N application, significantly highest net returns (₹77153) and BC ratio (3.27) were obtained by the application of NCU, net returns fetched by NCU was at par with the application of PU. However, the highest net return was obtained by the interaction between MWMb*NCU*WR while the highest BC ratio was recorded with MWMb*PU*WoR which was at par with MWMb*NCU*WR in fourth ZT maize. It was concluded that the basal application of NCU and residue retention in MWMb system found significantly superior for enhancing yield, profitability, resource-use efficiency and soil health in maize under conservation agriculture.
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T-9504
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