Thumbnail Image

Thesis

Browse

20181
Reset filters
Subject: Soil Science × Author: Anmol Singh × Start date: 2009 × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemRestricted
    Soil aggregate associated organic carbon and its impact on greenhouse gas emissions in different cropping system
    (Punjab Agricultural University, Ludhiana, 2018) Anmol Singh; Dheri, G. S.
    Crop production technologies may influence the potential of soil to act as a sink or source of global greenhouse gases (GHGs). Assessment of the impact of fertilizer and cropping system is required to identify best management practices (BMP) for soil carbon (C) sequestration and mitigation of GHG emissions. Nutrient management practices differentially influence organic C present within aggregates, which in time may affect rate of C mineralization and GHG emissions. The present study assessed the impact of long-term application of fertilizer and organic manures in maize-wheat (M-W) and rice-wheat (R-W) systems on aggregate stability, aggregate associated C and GHG emissions. Application of fertilizers and organic manures in both the cropping systems significantly improved the mean weight diameter and aggregate stability as compared to unfertilized control. The maximum increase in macro-aggregates was recorded in 100% NPK+farmyard manure (11.5%) under M-W and 100% NPK+straw incorporation (18.8%) under R-W. The higher concentration of C in recalcitrant fraction under R-W (38.6%) compared to M-W (16.6%) suggest that the soil conditions under R-W were more favorable for C stabilization. Irrespective of treatments total organic C was maximum in > 2 mm aggregate fraction with an average of 8.42 g kg-1 aggregate under M-W and 14.8 g kg-1 aggregate under R-W system. In general, long-term application of fertilizer integrated with organic manures (irrespective of aggregate fractions) improved total C and C fractions significantly as compared to sole application of fertilizer. The emission of CO2 and N2O was higher from macro-aggregates compared to micro-aggregates. Integrated use of fertilizer and organic manures may be the best management option for improving organic C and mitigating GHG emissions by increasing C stabilization and soil aggregation.