Nitrogen leaching losses under a less intensive farming and environment (LIFE) integrated system

A - Papers appearing in refereed journals

Webster, C. P., Conway, J. S., Crew, A. P. and Goulding, K. W. T. 2003. Nitrogen leaching losses under a less intensive farming and environment (LIFE) integrated system. Soil Use and Management. 19 (1), pp. 36-44.

AuthorsWebster, C. P., Conway, J. S., Crew, A. P. and Goulding, K. W. T.
Abstract

Less Intensive Farming and Environment (LIFE) management is a form of integrated farming which aims to meet farming's economic and environmental requirements. We used a farm-scale LIFE demonstration to measure nitrogen (N) leaching losses over a 6 year period (1995-2001) using ceramic suction cups and a meteorological model to give estimates of drainage volumes. Losses from the system averaged 49 kg N ha(-1), with an average drainage nitrate concentration of 15.5 mg N L-1. Rainfall and its distribution strongly influenced the loss, and drainage N concentration only fell below the nominal target of 11.3 mg N L-1 (the EU limit for potable water) in the two wettest seasons. Crop type did not have a significant effect on either postharvest mineral N (PHMN) in soil or the leaching loss in the subsequent winter. However PHMN and overwinter N leaching declined with increasing crop yield. Overwinter crop N uptake increased with early sowing: leaching loss was only 5 kg N ha(-1) under grass sown in early September. Measurements of PHMN, crop sowing date and drainage data were used to construct simple equations to predict average drainage N concentration under various scenarios. The large N loss from our site is partially attributable to soil type (shallow over limestone), indeed on similar soil the loss from a conventional farm nearby was greater. The LIFE practices of postharvest harrowing and late cereal sowing will minimize the need for agrochemical use but they stimulate mineralization and reduce plant N uptake in autumn, leaving more N at risk to leaching. Some assessment of all environmental impacts is needed if the benefits of integrated practices such as those used in LIFE are to be quantified.

KeywordsSoil Science
Year of Publication2003
JournalSoil Use and Management
Journal citation19 (1), pp. 36-44
Digital Object Identifier (DOI)doi:10.1079/SUM2002160
Open accessPublished as non-open access
Funder project or code441
511
ISSN02660032
PublisherWiley

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