Pilot-scale testing of renewable biocatalyst for swine manure treatment and mitigation of odorous VOCs, ammonia and hydrogen sulfide emissions

Comprehensive control of odors, hydrogen sulfide (H2S), ammonia (NH3), and greenhouse gas (GHG) emissions associated with swine production is a critical need. A pilot-scale experiment was conducted to evaluate surface-applied soybean peroxidase (SBP) and calcium peroxide (CaO2) as a manure additive to mitigate emissions of odorous volatile organic compounds (VOC) including dimethyl disulfide/methanethiol (DMDS/MT), dimethyl trisulfide, n-butyric acid, valeric acid, isovaleric acid, p-cresol, indole, and skatole. The secondary impact on emissions of NH3, H2S, and GHG was also measured. The SBP was tested at four treatments (2.28–45.7 kg/m2 manure) with CaO2(4.2% by weight of SBP) over 137 days. Significant reductions in VOC emissions were observed: DMDS/MT (36.2%–84.7%), p-cresol (53.1%–89.5%), and skatole (63.2%–92.5%). There was a corresponding significant reduction in NH3 (14.6%–67.6%), and significant increases in the greenhouse gases CH4 (32.7%–232%) and CO2 (20.8%–124%). The remaining emissions (including N2O) were not statistically different. At a cost relative to 0.8% of a marketed hog it appears that SBP/CaO2 treatment could be a promising option at the lowest (2.28 kg/m2) treatment rate for reducing odorous gas and NH3 emissions at swine operations, and field-scale testing is warranted

Effects of manure history and nitrogen fertilizer rate on sugar beet production in the northwest U.S.

Past manure applications effects on sugarbeet production needs to be assessed in the areas where manure applications to crop land are common. A study was conducted in Kimberly, Idaho in 2014 and 2016 to assess the effects of manure application history and N rates on sugarbeet production on a Portneuf silt loam (coarse-silty mixed mesic Durixerollic Calciorthid) soil. From 2004 to 2009, manure was applied to plots every two years (M1, total application = 60 tons per acre), every year (M2 total application = 106 tons per acre), or no manure (F, commercial fertilizer only). In spring 2014, the manure main plots were split in half with one half receiving a commercial fertilizer N rate treatment superimposed on the main plots in 2014 and the other half receiving the superimposed N rate treatments in 2016. In 2014 and 2016, the commercial fertilizer N rates were 0, 30, 56, 77, 100, 141, 180, and 202 pounds per acre. The study design was a randomized block split-plot with manure history as the main plot and N rate as the subplot. During both years of the study, N rate did not affect sugarbeet yields, but M1 and M2 treatments had higher sugarbeet root yields compared to the F treatment. Averaged across all N rates, root yields from both manured treatments were 12% and 36% greater than the F treatment in 2014 and 2016, respectively, although sugar yield was only significantly greater in 2016. Manure applications will impact sugarbeet production for several years after manure applications have ceased