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采用野外调查取样与室内分析相结合的方法,研究了水旱轮作条件下,不同免耕年限土壤主要理化特性的变化特点。结果表明:(1)水作及旱作后,随免耕年限延长土壤容重在免耕7~8年达到最大值,与常规耕作差异显著,长期免耕导致土壤板结;土壤pH值在免耕2~3年显著低于常规耕作,免耕致使土壤酸化。(2)水作及旱作后,免耕土壤有机质、全氮、速效氮、速效磷、速效钾均在表层(0-5 cm)富集。(3)水作及旱作后,免耕土壤耕层有机质、全氮均高于常规耕作,随免耕年限延长,免耕7~8年时明显下降;旱作后耕层土壤速效氮、速效磷变化特征与有机质和全氮一致,水作后免耕土壤速效氮含量高于常规耕作,但各免耕年限间无显著差异,土壤速效磷在免耕5~6年达到最大值,显著高于常规耕作,后随免耕年限延长变化趋于稳定;水作及旱作后,土壤速效钾在免耕5~6年内,与常规耕作均无显著差异,免耕7~8年达到最大值。水作与旱作相比,各肥力指标均表现为水作高于旱作。
The field survey sampling and indoor analysis were combined to study the characteristics of main physical and chemical characteristics of soils under different tillage periods under the conditions of runoff and drought. The results showed that: (1) Soil bulk density increased with the no-tillage time and reached the maximum value in 7-8 years after no-tillage, which was significantly different from conventional tillage. Long-term no-tillage led to soil compaction. 2 to 3 years was significantly lower than conventional farming, soilless soil acidification. (2) Soil organic matter, total nitrogen, available nitrogen, available phosphorus and available potassium in no-tillage soil were all enriched on the surface (0-5 cm) after watering and dry farming. (3) After irrigating and dry farming, the contents of organic matter and total nitrogen in topsoil of no-tillage soil were all higher than those of conventional tillage, The available phosphorus content was consistent with the organic matter and total nitrogen. The available nitrogen content in no-tillage soil after watering was higher than that in conventional tillage, but there was no significant difference among the no-tillage years. The content of available phosphorus in soil reached the maximum in no-till 5-6 years Higher than that of conventional tillage, followed by the prolongation of no-tillage. The change of soil available potassium in water-use and dry-farming was no significant difference compared with that of conventional tillage within 5 ~ 6 years of tillage, value. Water and dry farming compared to the indicators of fertility showed that water is higher than the dry land.