Understanding the interactions among organic manure chemical composition, decomposition and nitrogen (N) fertilization is critical for sustainable agriculture management. Six organic manures were incubated in a cultivated black soil with or without N addition for one year, and carbon dioxide (CO) emissions from these organic manures were monitored. Chemical compositions of the organic manures were determined by elemental analysis, proximate chemical analysis, and carbon (C)-13 nuclear magnetic resonance spectroscopy, and evaluated after cupric-oxide oxidation for lignin biomarkers. During the experimental period, 19-44% of manure C was decomposed without N addition, which decreased to 17-35% with N addition, except for the composted furfural residue with rice dregs. However, during different decomposition stages, N effect changed from stimulation to inhibition, or behaved as increasing inhibition. During stage 1 (days 0-100) when N stimulation effect reached a maximum, CO emissions from manure had positive relationships with labile C fraction indicators, including total sugars, soluble polyphenols, and lignin cinnamyl/vanillyl ratio regardless of N addition. N effect on manure decomposition was related to the C/N ratio and labile organic C content. During stage 2 (days 101-267), N effect shifted to inhibition, with CO emissions from manure negatively related to lignin vanillyl-units content. The magnitude of N inhibition increased linearly with the aromaticity of dissolved organic C, and was strengthened by nitrate in manure. Finally, N inhibition effect reached a maximum during stage 3 (days 268-365), increasing with higher aromatic C in manure. Critical factors for manure decomposition shifted from total sugars, soluble polyphenols, and lignin cinnamyl-units to recalcitrant lignin vanillyl-units and aromatic C fraction, which mediated the type and magnitude of N effect on decomposition. Our results suggested that the potential for enhancing soil C sequestration with organic manures would magnify under combined application with N fertilizer in the long term.
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http://dx.doi.org/10.1016/j.scitotenv.2017.02.033 | DOI Listing |
PLoS One
January 2025
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, Davis, California, United States of America.
In integrated crop-livestock systems, livestock graze on cover crops and deposit raw manure onto fields to improve soil health and fertility. However, enteric pathogens shed by grazing animals may be associated with foodborne pathogen contamination of produce influenced by fecal-soil microbial interactions. We analyzed 300 fecal samples (148 from sheep and 152 from goats) and 415 soil samples (272 from California and 143 from Minnesota) to investigate the effects of grazing and the presence of non-O157 Shiga toxin-producing Escherichia coli (STEC) or generic E.
View Article and Find Full Text PDFJ Anim Sci
January 2025
University of Reading, School of Agriculture, Policy and Development, Earley gate, RG6 6EU Reading, United Kingdom.
This study investigated the effects of different protein sources on feed intake, nutrient, and energy utilization, growth performance, and enteric methane (CH4) emissions in growing beef cattle, also evaluated against a pasture-based diet. Thirty-two Holstein × Angus growing beef were allocated to four dietary treatments: a total mixed ration (TMR) including solvent-extracted soybean meal as the main protein source (SB; n = 8), TMR with local brewers' spent grains (BSG; n = 8), TMR with local field beans (BNS; n = 8), and a diet consisting solely of fresh-cut Italian ryegrass (GRA; n = 8). Every four weeks, animals were moved to digestibility stalls within respiration chambers to measure nutrient intakes, energy and nitrogen (N) utilization, and enteric CH4 emissions.
View Article and Find Full Text PDFHeliyon
July 2024
Department of Business Sciences - Management & Innovation Systems/DISA-MIS, University of Salerno, Italy.
This article aims to provide a systematic review of the literature on animal biomass and biogas plants through an analysis of externalities and benefits in economic, social, and environmental terms. In recent years, the spread of biogas plants has played an important role, especially in rural areas, generating benefits not only for the individual farm but for entire communities, contributing to the reduction of energy poverty and, at the same time, promoting the production of energy and organic manure. In light of the findings, the study argues that: (a) more public subsidies are needed; (b) the deployment of an appropriate policy mix would encourage the spread of small and medium-sized plants, with a reduction in road transport; and (c) targeted and diversified investments are needed on a geographic-by-geographic basis.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 211135, PR China. Electronic address:
Hydroxyl radical (OH) plays a critical role in accelerating organic contaminant attenuation during water-table decline in paddy soil, but the impacts of widely applied agricultural amendments (e.g., organic manure, rice straw, and biochar) on these processes have been rarely explored.
View Article and Find Full Text PDFBMC Plant Biol
January 2025
Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia.
Background: Organic fertilizers are safer and more eco-friendly than chemical fertilizers; hence, organic fertilizers can be used to support sustainable farming. The effects of PGPRs are manifold in agriculture, especially in monoculture crops, where the soil needs to be modified to increase germination, yield, and disease resistance. The objective of this study was to assess the effects of PGPRs combined with fertilizer on the yield and productivity of canola.
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