Injection of Dicyandiamide-Treated Pig Slurry Reduced Ammonia Volatilization without Enhancing Soil Nitrous Oxide Emissions from No-Till Corn in Southern Brazil

Abstract

There is a lack of information on how placement in soil and nitrification inhibitors affects nitrous oxide (NO) and ammonia (NH) emissions from pig slurry (PS) applied under no-till (NT) conditions. Our objective was to determine the impact of injecting PS and treating it with the nitrification inhibitor dicyandiamide (DCD) on NH and NO emissions from soils under NT in subtropical southern Brazil. The emissions of these gases were compared for shallow (∼ 10 cm) injection and surface broadcasting of PS with and without DCD (8.1-10.0 kg ha; 6.5-8.4% of applied NH-N). Measurements were made at two sites during two summer growing seasons under NT corn crops. Injection reduced NH volatilization by 70% but increased NO emissions 2.4-fold (from 2628 to 6198 g NO N ha) compared with surface broadcast application. Adding DCD to PS inhibited nitrification and reduced NO emissions by an average of 28% (730 g NO-N ha) for surface broadcast and 66% (4105 g NO-N ha) for injection but did not increase NH volatilization. Consequently, NO emission factors were much higher for injection (3.6%) than for surface broadcast (1.3%) application and were reduced (0.9%) when DCD was added to injected PS. In conclusion, the injection of DCD-treated slurry is a recommendable practice for reducing NH and NO emissions when applying PS on NT corn in southern Brazil.

Short-term carbon dioxide emission under contrasting soil disturbance levels and organic amendments

“…Additionally, our results would support other research addressing N losses and soil availability (Chantigny et al, 2002;Yang et al, 2002;Aita et al, 2012;Chalhoub et al, 2013) and the parametrization of mathematical models (e.g., CENTURY, RothC, DAISY, PASTIS) assessing changes on soil organic C stocks according to soil management and fertilization practices (Bruun et al, 2003;Yokozawa et al, 2010;Chalhoub et al, 2013;Cong et al, 2014). Future long-term studies assessing changes in soil organic C stocks due to soil tillage practices and organic fertilization should also address concomitant ammonia and greenhouse gases emissions (i.e., CH 4 and N 2 O) from these practices (Aita et al, 2014b) to fully evaluate the environmental benefit of recycling such wastes in agricultural systems.…”

“…Although incorporation (Rochette et al, 2009) or injection (Aita et al, 2014b) of ammonia-rich swine slurry into the soil would be preferable to prevent NH 3 -N volatilization, swine slurry topdressing remains the usual practice in Brazilian no-till system. These practices can impact soil C and N dynamics by affecting soil CO 2 emissions (Aita et al, 2012).…”

Ammonia volatilization with swine slurry injection and use of nitrification inhibitor

“…The highest emissions occurred in the treatments with SS + DCD (12.72 mg kg ), both applied on the surface. Aita et al (2014) studied the injection of SS + DCD in sandy soil and verified that the emissions of NH 3 were smaller, in relation to the superficial application. For the limed sandy soil (pH 6.8) all treatments had higher NH 3 emissions, compared to the natural pH, except for the injected treatments, where the lowest emission was observed in the SS + DCD treatment (8.53 mg kg -1 ).…”

Long-term application of swine manure on soybean grown in no-till system in Savannah soils

“…These technical criteria take into account the extraction of nutrients, nutritional requirement of the crop, soil fertility and waste analysis (Correa et al, 2011). Successive applications of liquid swine manure in the same area may lead to environmental problems such as the possibility of contamination of the water table (Zaman and Blennerhassett, 2010;Gonzatto et al, 2013;Aita et al, 2014;Giacomini et al, 2014).…”