In situ microbial decomposition of rice residue through integrated nitrogen management under conservation tillage in wheat (Triticum aestivum L.)
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Date
2022
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Punjab Agricultural University, Ludhiana
Abstract
The present investigation entitled “In situ microbial decomposition of rice residue through integrated nitrogen management under conservation tillage in wheat (Triticum aestivum L.)” was carried out for two consecutive rabi seasons of 2017-18 and 2018-19 at two locations viz. Ludhiana and Ladhowal. Experiment I was laid out with 3 replications in split plot design, consisting of six nitrogen management options to hasten the microbial decomposition i.e. N1- no application of N i.e. control, N2- N120, N3- N120+ 3% urea spray on in-situ rice residue after harvesting paddy, N4- N120 (25% of total N added through FYM on rice residue just after paddy harvest and 75% N added through urea to the succeeding wheat), N5- N150+ 3% urea spray on in-situ rice residue after harvesting paddy and N6- N150 (25% of total N through FYM and 75% N through urea to the succeeding wheat) in main plots and four microbial sprays on in-situ rice residue after paddy harvest i.e. uninoculated control (M1), Aspergillus sp. (M2), Delftia sp. (M3) and consortia (Aspergillus sp.+ Delftia sp.) (M4) in sub plots. Experiment II was laid out in RBD with 3 replications consisting of ten treatments i.e. control, one, two and three sprays, each of Delftia sp., Aspergillus sp., consortia (Delftia sp.+ Aspergillus sp.). The treatment with one spray was initiated within two days of harvesting paddy and subsequent sprays (two and three sprays) were conducted at an interval of 10 days from previous spray. Growth attributes like plant height, number of tillers, DMA and LAI improved in N5, ultimately produced better yield attributes in terms of productive tillers, spike length, number of grains/spike leading to highest productivity of succeeding wheat as compared to other treatments. Micrometeorological observations (viz. lower canopy temperature, maximum NDVI and PAR interception), quality parameter (viz. protein content, hectolitre weight, dry and wet gluten content), phenology, N uptake by grain and straw were found to be higher in N5 at Ludhiana and Ladhowal during rabi 2017-18 and 2018-19. Microbial traits i.e. bacterial, fungal, CDB, SSB population, MBC, MBN, DHA and UA were maximum in N6 and the lowest in N1 and; NS N fixers and actinomycetes population were determined higher in N1. On the other hand, foliar application of Delftia sp. (M3) on in-situ rice residue improved the number of productive tillers, spike length, grain yield, harvest index, NDVI, PAR interception, quality aspect, N uptake by grain and straw over the uninoculated control. Maximum bacterial, CDB, SSB, NS N fixers, actinomycetes population as well as MBC, MBN, DHA, UA were found in M4, while maximum fungal population in M2. Trend for NUE indices (AE, PE аnd ARE) varied for different treatments. None of the interaction effects were found to be significant for any growth and yield components. In experiment II, growth parameters, yield attributing characters, NDVI, PAR interception, grain yield, phenology, N uptake by succeeding wheat grain and total N uptake, maximum microbial traits, MBC and MBN showed a non-significant increase with three sprays of Delftia sp. on in-situ rice residue (D3) over the uninoculated control and number of sprays of Aspergillus sp. (A1, A2, A3) during both the years of study at both the locations. The increase in grain yield with D3 over control ranged from 11.1-14.9% and 11.3-14.9% at Ludhiana and Ladhowal, respectively. Quality parameters, CDB, actinomycetes, NS N fixers and SSB population, DHA and UA were also found higher in D3 at most of the intervals and in C3 at some intervals. Fungal population was found maximum in A3. Microbial spray might have helped to increase wheat yield. Hence, spray of microbes under N @150 kg/ha regime increased the succeeding wheat yield with faster decomposition of rice residue.
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Rajbir Singh (2022). In situ microbial decomposition of rice residue through integrated nitrogen management under conservation tillage in wheat (Triticum aestivum L.) (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.