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为了探讨绿肥的改土效益,取得符合中国农业生产实际的可靠资料,1981年以来,全国绿肥试验网组织17个省(自治区),在22个土壤上进行了5年定位试验.结果表明,无论是在中国的南方或北方,旱地或水田,平均每年压入绿肥鲜草1500—2000公斤/亩,5年后土壤中有机质比不压绿肥的休闲地有明显提高,增加幅度为0.1—0.2%.而且,压绿肥后,土壤有机质的品质有所改善,活性有机质、总腐殖质含量和有机无机复合度均较休闲地明显提高.绿肥还能提高土壤氮素含量,改善土壤耕性,提高农作物抗病和抗逆性等能力,使农作物获得较高的产量.可见,绿肥的效果是多方面的.土壤有机质积累的限制因素很多,既和翻压绿肥本身有关,也与外界环境条件密切相联.耕作措施、绿肥的翻压量和质地以及土壤肥力等都影响着土壤有机质的积累.采用混播,适当推迟翻压和增加压量等对土壤有机质积累是有利的.在高肥力土壤上的,绿肥积累有机质效果不及中、低肥力土壤.因此,种植和利用绿肥,主要应在肥力较差的地上,才能取得较好的经济效益.
In order to explore the benefit of soil improvement for green manures and to obtain reliable data in line with the actual situation of agricultural production in China, the National Green Manure Experiment Network organized 17 provinces (autonomous regions) since 1981 and conducted a 5-year positioning experiment on 22 soils. The results show that no matter Is in the southern or northern China, dry land or paddy fields, the average annual fresh green grass pressed 1500-2000 kg / mu, 5 years after the organic matter in soil than the non-pressure green manure has significantly increased leisure, an increase of 0.1-0.2% Moreover, after the green manure was applied, the quality of soil organic matter was improved, and the content of active organic matter, total humus content and organic-inorganic compound content were both significantly increased compared with fallow land. Green manure also increased soil nitrogen content, improved soil tillage and increased crop resistance Disease and stress resistance and other crops, so that higher yields of crops can be seen that the effectiveness of green manure is multifarious. Soil organic matter accumulation of many limiting factors, both turn over green manure itself, but also with the external environmental conditions are closely linked Tillage measures, the amount of green manure and the quality of soil overpressure and soil fertility all affected the accumulation of soil organic matter .Using mixed broadcasting, appropriate postponement of turning pressure and increase of pressure on soil organic matter It is advantageous in the high fertility of the soil, manure accumulation of organic matter results in less, low soil fertility. Therefore, the cultivation and use of green manure, primarily in poor fertility of the earth, in order to achieve better economic efficiency.