Manure management practices applied to a seven‐course rotation on a sandy soil: effects on nitrate leaching

Abstract

This experiment tested whether it was possible to incorporate broiler litter (BL) or cattle farmyard manure (FYM) into a 7-yr arable rotation on a sandy soil without causing an increase in nitratenitrogen (NO 3 -N) leaching. Four manure treatments (with adjusted fertilizer inputs), varying in frequency and timing of application, were imposed on the rotation and compared with a control that received inorganic fertilizer according to recommended rates. Over seven winters, the annual average NO 3 -N leached from the inorganic fertilizer treatment (control) was 39 kg/ha in 183 mm drainage. Total manure N loadings over the period of the experiment ranged between 557 and 1719 kg/ha (80-246 kg/ha/yr) for the four treatments. Three of the four manure treatments significantly increased NO 3 -N leaching over the rotation (P < 0.001). Annual applications of FYM (1719 kg/ha manure N or 246 kg/ha/yr) increased NO 3 -N leaching by 39%. We hypothesize that this was due to increased mineralization of the organic N accumulating from repeated FYM applications. BL applied each year (1526 kg/ha manure N or 218 kg N/ha/yr) increased NO 3 -N leaching by 52% above the control; BL applied 5 of 7 yr (972 kg/ha manure N or 139 kg N/ha/yr on average) and including inadvisable autumn applications increased leaching by 50%. BL applied in late winter or early spring every 2-3 yr (557 kg/ha manure N or 80 kg N/ha/yr on average) resulted in NO 3 -N leaching similar to the control. This suggests that to avoid additional NO 3 -N leaching from manure use in an arable rotation, manure should not be applied every year and autumn applications should be avoided; there are real challenges where manure is used on an annual basis.

The effects of pig manure type and application timing and frequency on nitrate leaching from a seven‐course arable rotation on a retentive alluvial soil

“…However, there was little risk from FYM applications made in this period, probably related to its relatively low NH 4 -N content (Table 3); Sørensen & Rubaek (2012) noted that FYM could present a leaching risk when applied in autumn if the NH 4 -N content was high. Although we have demonstrated no additional risk from repeated FYM applications, this is in contrast to the experiment reported by Shepherd & Newell-Price (2013), where increased NO 3 -N leaching was attributed to a build-up of mineralizable N from repeated FYM applications. This difference may be because of the more retentive silt soil providing some protection to the organic matter.…”

“…Again, this is a positive message; organic manure N can be applied 5–6 yrs out of seven with no extra N leaching. These applications are more frequent than those reported by Shepherd & Newell‐Price () on a sandy soil, where it was necessary to reduce poultry manure applications to once in every 3 yrs to cause no additional NO 3 –N leaching. The difference may be due to the more retentive soil in this experiment.…”

“…Total yield of produce was no less than the control treatment (Table ), even though there were large decreases in inorganic fertilizer inputs after manure applications (Tables and ). Shepherd & Newell‐Price () similarly found that on a sandy soil receiving poultry manure or cattle FYM, yields were maintained or increased compared with the inorganic fertilizer control. This is a positive message; savings in manufactured fertilizer inputs after manure, with no loss of yield.…”

“…Few experiments have measured the medium-term effects of these practices. Shepherd & Newell-Price (2013) tested the effects of frequency and timing of cattle FYM and poultry litter over a seven-course arable crop rotation on a sandy soil. Broiler litter with its higher readily available N content posed a greater N leaching risk than FYM.…”

Crop Yield and Nitrous Oxide Emissions following Swine Manure Application: A Meta‐Analysis

“…For example, Schlegel et al (2015) evaluated soil physiochemical properties after 10 yr of swine manure application and found that swine manure did not affect soil P, soil N, soil C, organic matter, or electrical conductivity. However, other evidence suggests that repeated manure applications increases soil nutrients and subsequent risk of losses through leaching, runoff, or gas emission (Ball‐Coelho et al, 2004; Shepherd and Newell‐Price, 2013).…”