Application of manure from cattle fed with different diets affects soil properties and greenhouse gas emissions

  • Author / Creator
    Weber, Tien L
  • Cattle production contributes the largest portion of livestock agricultural greenhouse gas (GHG) emissions in Canada mostly in the form of methane (CH4). Efforts to reduce CH4 emissions have led to modification of diet composition for livestock, resulting in a corresponding change in manure properties. The release of nitrous oxide (N2O) and CH4 from manure is the second leading cause of GHG emissions in agriculture. However, the effect of diet modification on GHG emission from cattle manure has not been well studied. Therefore, I designed two laboratory incubation experiments to investigate how amending the soil with manure from cattle fed different diets affect GHG emissions and soil biogeochemical properties. Total nitrogen (N), total carbon (C), organic C (OC), C/N ratio, microbial biomass C, microbial biomass N, nitrate (NO3--N), ammonium (NH4+-N), available N (sum of NO3--N and NH4+-N) and GHG fluxes (carbon dioxide (CO2), N2O, and CH4) were measured throughout the experiments to understand the C and N cycles.The first incubation was conducted over 70 days. Manure from cattle fed a corn-based silage diet (CM) or a barley-based silage diet (BM) was applied to three soil types (collected from the upper 0-15 cm): Orthic Black Chernozem (OBC), Dark Brown Chernozem (DBC), and Orthic Gray Luvisol (OGL). Those treatments were compared with a control (CK) without manure application. The CO2, N2O, and CH4 emissions from the CK soil were lowest while amended soils amended had higher GHG emissions because the solubility of OC was increased by the addition of manure. The CO2 emissions were greatest in CM amendments across all soil type, likely resulting from a difference in C quality or another variable that was not investigated in this study. The N2O emissions were found to be greatest in BM amended OBC and OGL soils due to the variation in fecal and urinary forms of N. The CH4 emissions were highest from BM-amended soils in OBC and OGL soil types from the difference in location of starch digestion in the cattle’s rumen which may have altered the properties of the BM and CM amendments.The second incubation was conducted over 85 days. The experiment used (0-15 cm) soil of neutral fine-textured Orthic Dark Brown Chernozem (DBC), an acidic fine-textured Orthic Gray Luvisol (OGL), and an acidic coarse-textured Orthic Black Chernozem (OBC) amended with manure from cattle fed a barley-based diet (BM), a barley-based diet supplemented with the methane inhibitor 3-nitrooxypropanol (3-NOP; 3NOPM), or composted 3NOPM (3NOPC). Those treatments were compared with a control (CK) without manure application. The BM had the lowest nitrate (NO3--N) concentration and higher C/N ratio and the BM-amended soil had the highest CO2 emissions in the OBC and OGL amended soils. The 3NOPC resulted in lower N2O emissions than 3NOPM across all soil types from stabilized C and N that limited microbial activity. The OGL soil had the highest CO2, N2O, and CH4 flux from the low initial pH that stimulated labile C consumption. The positive CH4 emissions from OGL and DBC clay loam soils comes from the ability to retain water and promote methanogen transport. In conclusion, our results from the first experiment found that manure type, soil type, and their interaction significantly (α = 0.05) affected GHG emissions, which were the greatest for BM-amended and least for CK soils. Therefore, feeding cattle corn- rather than barley-based diet may be more environmentally friendly, specifically if the manure is applied to coarse-textured soils. Our results from the second experiment show that GHG emissions for composted manure from cattle fed 3-NOP were the lowest, indicating that 3-NOP supplementation of cattle diets has the potential to reduce total GHG emissions, especially in neutral soils. Further research is needed to investigate the effect on GHG emissions of manure application from cattle fed various diets in the field and in other soil types.

  • Subjects / Keywords
  • Graduation date
    Spring 2019
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
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