Regular applications of poultry litter to a sandy arable soil: effects on nitrate leaching and nitrogen balance
✍ Scribed by Shepherd, Mark; Bhogal, Anne
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 247 KB
- Volume
- 78
- Category
- Article
- ISSN
- 0022-5142
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✦ Synopsis
Intensive poultry units often have insufficient land for spreading manure at agronomically and environmentally acceptable rates. This experiment measured the e †ects of annual applications, at several rates, on nitrate-N leaching and the soilÈcrop N balance on a sandy soil. Poultry litter from a broiler unit was applied each autumn 1992È1995. Total loadings on the main experiment area (instrumented with ceramic and TeÑon water samplers at 1É0 and 1É5 m, and monolith lysimeters, 1É5 m deep) were 0, 60 and 150 t ha~1. Additional plots (not instrumented) received 30, 90 or 120 t ha~1. There was good agreement in the nitrate-N concentrations measured by the TeÑon and ceramic water samplers and the lysimeters ; all three methods gave acceptable measurements of nitrate leaching on structureless sandy soils. Autumn applications of poultry manure should be avoided : leaching was much greater than when delayed into December. At rates of broiler litter which supplied more N than the crop required (generally above 10 t ha~1 each year), nitrate-N leaching losses were large ; at the largest application rate (akin to a disposal, rather than a planned fertiliser strategy), concentrations peaked at c 500 mg litre~1 N. Despite the movement of dissolved organic carbon to 1 m depth, the N concentration proÐles measured by the water samplers did not provide clear evidence of subsoil denitriÐcation. A nitrogen balance sheet, based on available N applied (as either fertiliser or manure) with some adjustment for mineralisation of the manureÏs organic fraction (10% annually) and for volatilisation (15%) was strongly correlated with soil mineral N each spring.