Measurement of nitrate leaching losses from arable plots under different nitrogen input regimes

Abstract

Abstract. Leaching losses of nitrate‐nitrogen were measured from a set of eight hydrologically isolated plots on a clay loam soil over the period from September 1987 to February 1990. Variable drainflow recovery from the plots hampered accurate estimation of nitrate loading, but results suggest that, when inorganic nitrogen fertilizer is applied up to the recommended amount, there is little influence of the amount applied on the amount leached. We did, however, observe the following effects on nitrate leaching: leguminous green manure incorporated in autumn increased leaching of nitrate‐nitrogen by 10–15 kg per hectare during the winter; autumn cultivation caused some increase in leaching compared with no cultivation in one year; some systematic variations in nitrate leaching occurred between years and between plots, but were unrelated to treatments. From the results we conclude that green manuring does not provide sufficient nitrogen for organically grown crops on this soil but contributes significantly to nitrate leaching, and that growing spring cereals, with the land remaining in stubble as long as possible in autumn, may be the best strategy to minimize nitrate leaching.

The effect of water table depth on emissions of N2O from a grassland soil

“…This area has an average rainfall of 895 mm and a mean annual air temperature of 7.4 °C and the soil is at field capacity from mid‐October to early March (Francis, 1981). The soil is an imperfectly drained gleysol (FAO–UNESCO classification), with a topsoil (0–15 cm) of sandy loam texture (21% clay, 45% silt, 34% sand), underlain by clay loam (15–30 cm) with a moderate medium subangular blocky structure; the B horizon (30–72 cm) has a silty clay loam to clay loam texture with a weak medium angular blocky structure (Vinten et al ., 1991). The field had been grazed in previous years and an area had been fenced off and treated as for silage grassland for a year prior to setting up this experiment.…”

The fate ofEscherichia coliandE. coliO157 in cattle slurry after application to land

“…I). The drained plots each had a nominal area of 600 m 2 and were instrumented with tipping bucket flowmeters and water sampling devices (Vinten et al 1991). Drainage from one half of each plot, and surface run-off from the other, was sampled.…”

Field evaluation of models of denitrification linked to nitrate leaching for aggregated soil

“…Plots are artificially drained and hydrologically isolated. Tipping bucket flowmeters measured drainflow and flowweighted samples of drainage water were calculated (Vinten et al, 1991a).…”