Nutrient Runoff Losses from Liquid Dairy Manure Applied 
with Low‐Disturbance Methods

Abstract

Manure applied to cropland is a source of phosphorus (P) and nitrogen (N) in surface runoff and can contribute to impairment of surface waters. Tillage immediately after application incorporates manure into the soil, which may reduce nutrient loss in runoff as well as N loss via NH volatilization. However, tillage also incorporates crop residue, which reduces surface cover and may increase erosion potential. We applied liquid dairy manure in a silage corn ( L.)-cereal rye ( L.) cover crop system in late October using methods designed to incorporate manure with minimal soil and residue disturbance. These include strip-till injection and tine aerator-band manure application, which were compared with standard broadcast application, either incorporated with a disk or left on the surface. Runoff was generated with a portable rainfall simulator (42 mm h for 30 min) three separate times: (i) 2 to 5 d after the October manure application, (ii) in early spring, and (iii) after tillage and planting. In the postmanure application runoff, the highest losses of total P and dissolved reactive P were from surface-applied manure. Dissolved P loss was reduced 98% by strip-till injection; this result was not statistically different from the no-manure control. Reductions from the aerator band method and disk incorporation were 53 and 80%, respectively. Total P losses followed a similar pattern, with 87% reduction from injected manure. Runoff losses of N had generally similar patterns to those of P. Losses of P and N were, in most cases, lower in the spring rain simulations with fewer significant treatment effects. Overall, results show that low-disturbance manure application methods can significantly reduce nutrient runoff losses compared with surface application while maintaining residue cover better than incorporation by tillage.

Runoff water quality after low‐disturbance manure application in an alfalfa–grass hay crop forage system

“…Surface broadcast application, whereby liquid manure (<6% total solids) is applied to the soil surface without incorporation into the soil, is the most common application method. Although it is less labor intensive than manure injection or tillage incorporation, runoff N and P loss risk is higher with broadcast manure application (Jokela, Coblentz, & Hoffman, 2012; Jokela, Sherman, & Cavadini, 2016; Maguire et al., 2011; Vadas et al., 2017; Williams, King, Ford, Buda, & Kennedy, 2016). In addition, liquid dairy manure has considerable ammonia N (NH 3 –N) that is subject to rapid loss to the atmosphere and deposition off‐site if manure is not incorporated or injected in to the soil (Apsimon, Kruse, & Bell, 1987; Sommer & Hutchings, 2001).…”

Influence of low‐disturbance fall liquid dairy manure application on corn silage yield, soil nitrate, and rye cover crop growth

“…Strip‐till, aerator/band, and broadcast‐surf (mean, 42.8%) had a significantly larger fraction of large macroaggregates compared with fertilizer N plots (mean, 32.1%). Other studies have shown the beneficial effects of dairy manure on soil quality physical measures, including runoff potential (Jokela et al., 2009, 2016). In our study, manure treatments maintained higher total soil C and N and better soil structure as measured by MWD compared with fertilizer N treatments.…”

“…Nitrous oxide (N 2 O) is also a gaseous loss pathway for N, with fluxes tending to increase with incorporated manure (Chantigny et al., 2010; Sistani, Warren, Lovanh, Higgins, & Shearer, 2010). Because manure contains abundant N and phosphorus (P), field application and subsequent runoff/leaching can transport N and P in surface water runoff and leachate, posing a water quality risk (Eghball & Gilley, 1999; Jokela, Sherman, & Cavadini, 2016; Kovar, Moorman, Singer, Cambardella, & Tomer, 2011). Whether from manure or fertilizer, high N application rates increase N leaching risk to subsurface drainage and/or shallow groundwater (Al‐Kaisi & Licht, 2004; Dinnes et al., 2002; Halvorson, Wienhold, & Black, 2001; Sela et al., 2016; van Es et al., 2019; van Es, Sogbedji, & Schindelbeck, 2006).…”

“…Although it is beneficial, manure incorporation with conventional tillage increases erosion potential compared with low‐disturbance manure application methods (LDMA), where the goal is to minimize soil disturbance (Maguire et al., 2011). Banding/aeration and shallow disk/coulter injection are LDMA methods that can also effectively reduce NH 3 –N volatilization (up to 70 and 95% lower, respectively) and increase soil N availability compared with broadcast application, where large NH 3 –N losses occur (Bittman et al., 2005; Dell et al., 2012; Hansen, Sommer, & Madsen, 2003; Jokela et al., 2016; Powell et al., 2011). However, impacts of LDMA on crop yield potential have been mixed, ranging from neutral to negative (Dell et al., 2012; Powell et al., 2011; Sawyer, Schmitt, Hoeft, Siemens, & Vanderholm, 1991).…”

Impacts of low‐disturbance dairy manure incorporation on ammonia and greenhouse gas fluxes in a corn silage–winter rye cover crop system

“…Ammonia (NH 3 ) is considered a secondary GHG because a portion of N-containing fertilizers (particularly urea) can contribute to greater NH 3 fluxes compared with N sources incorporated into the soil (Dell et al, 2012;Duncan et al, 2017;Huijsmans et al, 2003;Powell et al, 2011;Sajeev et al, 2018;Webb et al, 2014;Wulf et al, 2002). Several studies have also demonstrated that incorporation of livestock manure not only conserves NH 3 but also substantially reduces surface runoff water N and phosphorus (P) loss risk in both corn and hay crop forage production fields (Jokela et al, 2012(Jokela et al, , 2016Sherman et al, 2020a). Soil moisture is an important factor affecting soil C and N transformations, including N 2 O fluxes related to changes in nitrification-denitrification reactions (Ball et al, 1999;Dalal et al, 2010;Gagnon et al, 2011;Kool et al, 2011;Liu et al, 2006;Perala et al, 2006;Thangarajan et al, 2013).…”