Nitrogen mass balance in fields irrigated with liquid swine waste

Abstract

Over the past 15-years, swine-producing confined animal feeding operations (CAFOs) have proliferated throughout the Southeastern United States, particularly in North Carolina. Waste at these facilities is collected in open-air lagoons and the liquid phase is land-applied as fertilizer by sprinkler irrigation. Numerous investigations have focused on individual aspects of the fate of nitrogenous liquid waste, but none has attempted a comprehensive analysis of post-application transformations and losses. On three occasions, we experimentally applied liquid swine waste at typical industry doses of 1.2 and 2.5 cm-ha (40-130 kg N ha À1 ) to carefully defined plots in an active spray field on a representative North Carolina CAFO and constructed a nitrogen mass balance for the waste by assessing most N pools and transformations in post-application observation periods of 14-19 days. We consistently recovered more N than applied, by an average of 126%. This was likely due to mineralization of endogenous organic-N, a reservoir that was not measured. Plant assimilation clearly represented the most important N sink for this fertilizer type, accounting for 25-117% of the applied N. Offsite loss to leaching and volatilization and onsite accumulation in the inorganic phase and in microbial biomass all assumed secondary and roughly equal importance; each term represented about 5-20% of the applied N. Denitrification was inconsequential in N loss from a mass standpoint, accounting for 2% of the effluent. The post-application fate of N in liquid swine waste did not differ fundamentally from other organic and inorganic fertilizers, as the relative importance of all loss and storage terms fell within the ranges of values given for other fertilizers. However, liquid swine waste did differ from other N fertilizers in the rate of processing. Transformations occurred rapidly due to the immediate post-application contact of liquid swine waste-N with plant roots and microbes in a form (NH 4 + -N) immediately available for use.

Soil fertility status and nutrients provided to spring barley (Hordeum distichon L.) by pig slurry

“…The addition of PS has been reported to improve the N status of soils for agricultural or environmental purposes (Chantigny et al, 2001;Daudén and Quílez, 2004;Whalen and DeBerardinis, 2007;Cela et al, 2011). Although the total N in the PS (1.00-1.41 g total M kg -1 ) is lower than Chantigny et al (2001) at 86 g total N kg -1 , our results are still consistent with the literature because at all stages of sampling, D1 and D2 plots have higher total N than control due to PS additions.…”

“…Contents of NO3 --N in PC2-D2 and CS2-D2 are 7X (109 mg NO3 --N kg -1 vs. 15.2 mg NH4 + -N kg -1 ) and 10X (73.6 mg NO3 --N kg -1 vs. 7.3 mg NH4 + -N kg -1 ), respectively compared to NH4 + -N in the same sampling events. The higher amounts of NO3 --N compared to NH4 + -N after two time additions of PS in the study site is consistent with nitrification of NH4 + -N in PS added to soils in Canada (Chantigny et al, 2001;Whalen and DeBerardinis, 2007).…”

Soil nitrogen response to coupling cover crops with manure injection

“…Nitrate-N leaching losses have been reported after application of liquid swine manure in agricultural systems. Experiments conducted in North Carolina spray fields reported that leaching losses below 20 cm after application of liquid swine manure ranged from 8 to 45 kg N ha -1 , which represented on average 13% of applied manure N (Whalen and DeBerardinis 2007). Average annual tile drain water NO 3 -N loading loss for a cornsoybean rotation amended with injected liquid swine manure ranged from 12 to 40 kg N ha -1 (6 year average 20 kg N ha -1 ), which was not significantly different than average annual tile NO 3 -N loading loss after application of similar amounts of fertilizer N (Bakhsh et al 2005).…”

“…Spring barley recovered *50% of cattle slurry manure N within 50 days of plant emergence in spring barley cropping systems (Peterson 2006). Whalen and DeBerardinis (2007) applied liquid swine manure at low and high rates to a spray field in North Carolina planted to coastal bermudagrass in summer and seeded to tall fescue in winter. They constructed N budgets for the period spanning 14-19 days post-application.…”

Nitrogen Budget and Ammonia Volatilization in Paddy Fields Fertilized With Liquid Cattle Waste

“…Nitrate can be reduced to N 2 by denitrifying bacteria in anaerobic micro zones and is then lost to the atmosphere. Some research has evaluated the nitrogen mass balance in grassland irrigated with liquid swine waste at a typical nitrogen load (40-130 kg N ha −1 ) (Whalen and DeBerardinis 2007). Those authors found that plant assimilation represented the most important nitrogen sink, whereas leaching, volatilization, and accumulation in the inorganic phase assumed roughly equal importance.…”