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To develop guidelines for estimating the effect of straw incorporation on N budgets (New code NT1505) - NT0501

Description
See NT1505.

NT0501. N requirements of straw incorporation.

Straw contains N, which is lost during burning. Repeated incorporation of straw leads to accumulation of soil N, which may eventually result in enhanced N mineralisation. This extra nitrate may lead to increased over-winter leaching or may be utilised by crops and reduce their requirement for fertiliser N. The time required for straw incorporation to cause significant increases in mineralisation of soil N is unknown. This study will aim to provide improved guidance on the short and long term N requirements of crops grown on soils with the incorporation of cereal straw. 3 cultivation treatments will be investigated: straw incorporation by shallow cultivation (10 cm); straw incorporation by deep ploughing (20 cm); and straw burning, followed by shallow cultivation (10 cm). 8 N treatments (0 to 320 kg/ha) will also be evaluated. Soil samples will be analysed for mineral N and crops grown will be harvested and analysed for yield and grain N (all plots) and straw N (burnt plots). Guidelines will also be provided for extreme soil types, such as boulder clay, and light-textured soils. Further experiments will determine the effects on growth of winter wheat, barley, oats and sugar beet of the following cultivation treatments: baling and removal of straw, shallow cultivation for weed control and ploughing; chopping of straw, surface cultivation for weed control and ploughing; and chopping of straw, which will then be left undisturbed until ploughing. Data obtained in this study will contribute to a wider understanding of the N cycle, with particular reference to the long term implications of straw incorporation and N lock-up and release associated with organic matter.
Objective
To provide improved guidance on the short and long term
nitrogen requirements where cereal straw is incorporated.

To provide guidelines for extreme soil types, ie. boulder
clay (/010) and light-textured soils.

To investigate the effect of straw disposal methods.
Time-Scale and Cost
From: 1991

To: 1995

Cost: £330,000
Contractor / Funded Organisations
ADAS UK Ltd.
Keywords
              
Fields of Study
Fertilisers and Nitrate Pollution