اثر مدیریت خاکورزی و محصول بر فرسایش خاک در مرکز کرواسی

The incorporation of chopped wheat (Triticum aestivum L.) straw into soil by tine cultivation (non-soil inversion) or ploughing was compared with burning straw followed by tine cultivation at six sites in England over a period of 11 years. Three sites had clay soils and three silty clay loam soils. Effects of straw management on weed incidence, take-all (Gaeumannomyces graminis var. tritici) infection and grain yield of following wheat crops and occasional break crops were studied. Soil mineral nitrogen and organic matter contents were measured at the end of the study. Incorporating straw by tines rather than burning reduced mean yield at all but one site. The yield reduction from tine incorporation ranged from 5 to 8% on clay soils and 3–18% on silty clay loam soils. Ploughing straw into soil only had an occasional adverse effect on yield of following crops. Much of the yield penalty associated with tine incorporation of straw was attributed to weed competition by Bromus spp. Difficulties in preparing a good seedbed, resulting in variable plant emergence, was the other main cause of lower yields with tine incorporation and in situations where plough incorporation reduced yields compared to burning straw. Method of straw disposal had no consistent effect on take-all infection. The effects of straw incorporation on soil mineral nitrogen and organic matter contents were small and inconsistent. There was no consistent effect of straw management practice on yield response to additional autumn application of nitrogen fertiliser. These results demonstrate that on those soils where ploughing is preferred, it is a suitable option for disposing of straw. Where non-ploughing methods have traditionally been used after straw burning they can still be employed with success, but occasional ploughing or planting of suitable break crops may be required to control grass weeds.

During the 1970s and 1980s, declining demand for cereal straw in the UK and increased production of cereals resulted in a surplus of straw, the majority being burnt in the field. By 1984, 6 million tonnes of straw was being burnt, representing 60% of the wheat growing area (Anon., 1992). This highly visible activity occasionally caused significant damage to hedges, trees and property, and caused public outcry each year. A report by The Royal Commission on Environmental Pollution (1984) recommended a ban on straw burning and this was introduced from autumn 1992. By 1992 the amount of straw burnt had reduced to about 2 million tonnes. Previous work had demonstrated the potential for buried straw to affect the growth and yield of following wheat crops (Oliphant, 1982). With changes in farming practices and a much wider range of soil cultivation equipment available, a new study was designed jointly by ADAS (formerly known as the Agricultural Development and Advisory Service) and the former Agriculture and Food Research Council (AFRC). This started in autumn 1983 and tested, on large plots, a range of options appropriate to different soil types and sites. This paper reports some of the results obtained during a 11-year period at six sites. The experiment investigated method of incorporating or burning straw on crop establishment, grain yield, weed and disease incidence, and soil mineral nitrogen and organic matter contents.