Evaluation of Cover Crop and Reduced Cultivation for Reducing Nitrate Leaching in Ireland

Abstract

Nitrate (NO(3)) loss from arable systems to surface and groundwater has attracted considerable attention in recent years in Ireland. Little information exists under Irish conditions, which are wet and temperate, on the effects of winter cover crops and different tillage techniques on NO(3) leaching. This study investigated the efficacy of such practices in reducing NO(3) leaching from a spring barley (Hordeum vulgare L.) system in the Barrow River valley, southeast Ireland. The study compared the effect of two tillage systems (plow-based tillage and noninversion tillage) and two over-winter alternatives (no vegetative cover and a mustard cover crop) on soil solution NO(3) concentrations at 90 cm depth over two winter drainage seasons (2003/04 and 2004/05). Soil samples were taken and analyzed for inorganic N. During both years of the study, the use of a mustard cover crop significantly reduced NO(3) losses for the plowed and reduced cultivation treatments. Mean soil solution NO(3) concentrations were between 38 and 70% lower when a cover crop was used, and total N load lost over the winter was between 18 and 83% lower. Results from this study highlight the importance of drainage volume and winter temperatures on NO(3) concentrations in soil solution and overall N load lost. It is suggested that cover crops will be of particular value in reducing NO(3) loss in temperate regions with mild winters, where winter N mineralization is important and high winter temperatures favor a long growing season.

The effect of renovation of long-term temperate grassland on N2O emissions and N leaching from contrasting soils

“…This study adds to the evidence of Hooker et al (2008) and Premrov et al (2014) who found no significant difference in leaching from CT and MT soils in Ireland.…”

“…There are conflicting reports on the effect of tillage method on N leaching. Some authors reported a reduction in N leaching losses in arable crops (Dinnes et al, 2002;Syswerda et al, 2012) while others did not see this effect in tillage soils in Ireland (Hooker et al, 2008;Premrov et al, 1014). However this might not be true for permanent grassland and the effect of tillage method may also depend on soil type (Hansen et al, 1997) as well as climatic conditions.…”

Soil mineral nitrogen and microbial parameters as influenced by catch crops and straw management

“…Catch crops decreased mineral nitrogen (N min ) content in both soil layers (0-40 cm and 40-80 cm) compared with the treatment without catch crops. Our research data agree with those of other researchers, who found less nitrogen (not exceeding European Union's allowable limits) in soil leachate after cultivation of catch crops in a crop rotation (Hooker et al, 2008). Legumes, as the postharvest catch crop, are not effective for nitrogen capture from the soil due to symbiotic nitrogen fixation.…”

Little Potential of Spring Wheat Genotypes as a Strategy to Reduce Nitrogen Leaching in Central Europe

“…Nitrate leaching for spring wheat (Table 3) was within the range reported in other studies for spring wheat (4 to 12 g N m´2; [21]) or spring cereals, e.g., 0.7 to 7.5 g N m´2 [32] and 1.61 to 9.63 g N m´2 [33]. The percentage of the NO 3 -N leaching to the fertilizer N input (14%) was in range of the 0.10 reported by Uhlen [21] for spring wheat grown in a similar climate.…”