Greenhouse Gas Emissions (GHGs) and N Losses from a Two-Year Field Study of Manure Application Under Corn (Zea Mays L.) Production

Land application of solid beef manure may prompt greenhouse gases (GHGs) - nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) emissions. Nitrogen (N) in manure can also be lost through ammonia volatilization (NH3), leaching (NO3-), denitrification, and erosion. The objectives of this research were to assess the effects of (i) land application of solid beef manure (SM) on emission of GHGs, NH3 volatilization, and corn (Zea mays L.) yield, (ii) soil moisture [(30, 60, and 90% water-holding capacity (WHC)] on GHGs and NH3 emissions from urea and manure application, and (iii) soil temperature (5, 10, 15, and 25?C) on GHGs and NH3 emissions from urea and manure amended Fargo-Ryan silty clay soil of the RRV. The two-year growing season cumulative N2O emission (cN2O) ranged from 0.3 (non-fertilized, NF) to 1.2 (urea only, UO) kg N ha-1. The UO reduced cumulative carbon dioxide (cCO2) by 42% compared to manure N sources. The cumulative CH4 (cCH4) emission ranged from -0.03 to 0.23 kg CH4-C ha-1 CH4-C ha-1, with the highest emission from manure with straw bedding (BM). Manure reduced cNH3 by ~11% compared to UO. Cumulative soil N in 2017 were significantly greater by 11%, respectively, compared to 2016. Nitrogen source did not show any difference in grain yield and grain N uptake in field study. In the laboratory, across WHC levels, 1.01% of the total applied N was lost as N2O at 60% WHC from urea treated soil. Soil CO2 from manure was up to two times the emission from CF treated soils. The cumulative NH3 volatilization loss from soil ranged from 29.4 to 1250.5 ?g NH3-N kg?1 soil, with the highest loss from CF amended soils at 30% WHC. In addition, laboratory study showed cumulative GHGs and NH3 emission generally increased with increase in temperature, with the highest emission observed at 25 ?C. The results highlight the challenge of meeting crop nutrients demand while reducing GHG emissions by selection of an N source.USDA NIFA Award No. 2015-67020-2345