【作者】 何玉梅；

【导师】 张仁陟；

【作者基本信息】 甘肃农业大学 ， 植物营养学， 2006， 硕士

【摘要】 以传统耕作(T)为对照,应用土壤微生物学和土壤学的方法,研究了免耕秸秆覆盖(NTS)、免耕(NT)、秸秆还田(TS)三种保护性耕作措施下黄土高原西部旱作农业区小麦地和豌豆地耕层土壤微生物数量及多样性规律、土壤微生物特殊生理类群分布规律,结果表明:1.不同耕作措施对土壤真菌数量具有不同程度的影响,并呈现如下规律:(1)在不同季节和不同种植方式下,免耕处理的土壤真菌数量均高于翻耕处理,秸秆覆盖处理则显著高于传统耕作处理;(2)在各处理间,豌豆地土壤真菌总数均显著多于小麦地;(3)豌豆地土壤真菌总数,T处理与另外三种处理差异显著,且NTS处理与T处理达到极显著水平;(4)不同保护性耕作土壤真菌数量的季节性的变化不尽相同;在播种前,菌量上下层呈现明显的分层现象;而收获后,上层和下层却高低不定,交替出现高峰值。2应用本试验研究方法,免耕、秸秆覆盖和种植方式对土壤真菌群落结构的影响主要集中于优势属的组成:(1)就免耕覆盖比较,对于覆盖、种植方式、季节和土层深度各因子,表征土壤真菌群落结构多样性的Simpson(J)指数平均数大小排序是NTS >TS处理,NT>T处理,但变化不明显;Shannon(H`)指数受免耕的影响很大;(2)就豌豆地而言:三种保护性耕作措施土壤真菌群落均匀性均高于传统耕作;(3)与没有秸秆覆盖处理比较,秸秆覆盖处理表征土壤真菌群落结构多样性的Simpson(J)指数平均数大小排序是T<TS处理,NT<NTS处理;Shannon(H`)指数受免耕的影响很大。3土壤放线菌数量变化与土壤真菌数量变化趋势相似:(1)免耕处理条件下的放线菌数量无论是季节因素还是种植方式的影响都均高于翻耕处理条件下的放线菌数量;秸秆覆盖明显增加了土壤放线菌的数量;(2)在各处理间,豌豆地土壤放线菌总数均显著多于小麦地,种植方式对土壤放线菌数量的影响差异显著。4应用本试验研究方法,免耕、秸秆覆盖和种植方式对土壤放线菌群落结构的影响主要集中于优势属的组成:(1)种植方式对主要放线菌属无太大影响。就免耕覆盖比较,这对于种植方式、覆盖、季节和土层深度各因子,表征土壤放线菌群落结构多样性的Simpson(J)指数平均数大小排序是NTS >TS处理,NT>T处理。Shannon(H)指数受免耕的影响很大;(2)豌豆地:Shannon(H)指数NT处理比T处理在4月份增加了43.5%,7月份增幅更多还原

【Abstract】 On basis of the principles of soil microbiology and pedology, an experiment was conducted to compare the effects of conventional tillage (T) and three conservation tillage practices on population, diversity and functional groups of soil microorganism of pea field and wheat field in semi-arid areas of the Loess Plateau. The three conservational tillage practices included conventional tillage with straw incorporated (TS), no-till with no straw cover (NT), no-till with stubble retention (NTS). The main research results are as the follows:1. Population of soil fungi was affected by the various tillage treatments to different extent as the follows.(1)Treatments of no-till resulted in greater population of soil fungi than the conventional tillage, which was not influenced by the changes of season and cultivable mode. The conventional tillage covered with straw further significantly increased soil fungi quantity.(2)Total quantity of soil fungi the pea field was consistently higher than the wheat field in all the tillage treatments.(3)The pea field:soil fungi total quantities of the three conservation tillage treatments were significantly higher than the T treatment, in which the effect of NTS reached the extremely remarkable evel.(4)The influence of the different conservation tillage varied on soil fungi population with seasonal changes. Before sowing, soil fungi population significantly existed stratification among the various layers of soil profile. After harvesting, however, the upper formation and the lower level height do not decide actually, appears the crest value in turn.2. Under conditions of this experiment, superiority community resulting from treatments of straw incorporated, no-till with no straw cover, and the cultivable mode was the major factor for influencing on soil fungi composition.(1)In treatment of No-till with stubble retention, soil fungi community structure multiple Simpson (J) index, though not very obvious, could be ranged as NTS >TS and NT>CT, which involved with factors such as cultivable mode, straw covering, season changes and soil depths. Shannon (H) index were remarkable affected by no-till with no straw cover.(2)As far as the pea field concerned , all the three conservation tillage methods resulted in better uniformity of soil fungi community in comparison with the traditional cultivation.(3)In comparison to no-till without stubble treatment, conventional tillage with straw incorporated attributed soil fungi community structure multiple Simpson (J) index were T<TS, NT<NTS and Shannon (H) index were greatly affected by no-till.更多还原