【作者】 李亚莉；

【导师】 朱建兰；

【作者基本信息】 甘肃农业大学 ， 植物病理学， 2005， 硕士

【摘要】 本论文主要研究了秸秆覆盖还田全程节水下,耕作方式和灌水量对春小麦土壤真菌、细菌、放线菌,土壤微生物生理类群,土壤线虫,小麦根病的影响。结果表明: 1 耕作方式和灌水量对春小麦土壤真菌、细菌、放线菌数量的影响 这三类微生物数量均为秸秆还田>免耕>常规,其中秸秆还田处理是常规处理的2～3倍,免耕是常规的1～2倍。真菌总数随灌水量的增加而减小;细菌和放线菌总数随灌水量的增加呈先增大后减小,在灌水量为1350～1725m~3/hm~2时达到最大,但灌水量对细菌总数影响不大。在季节变化方面,三种微生物均呈单峰曲线,真菌和放线菌在抽穗期达到最大,收获后最小,而细菌总数在拔节期达到最大。在大多处理中,真菌优势种群是镰刀菌(Fusarium),细菌优势种群是WJ1和WJ2,但次优势种群存在明显差异。 2 耕作方式和灌水量对春小麦土壤微生物生理类群数量的影响 芽孢杆菌、硝化细菌、好气固氮菌、好气纤解菌的数量表现为秸秆还田>免耕>常规,秸秆还田中生理类群数量是常规的2～3倍,免耕是常规的1～2倍。反硝化细菌、嫌气固氮菌、嫌气纤解菌的数量表现为免耕>秸秆还田>常规,反硝化细菌在免耕和秸秆还田中的数量是常规的2～3倍,但嫌气固氮菌和嫌气纤解菌在秸秆还田和免耕中数量是常规的1倍多。随着灌水量的增大,硝化细菌总数呈下降趋势,反硝化细菌呈上升趋势,芽孢杆菌、好气固氮菌、嫌气固氮菌的数量在灌水量为975～1350m~3/hm~2时最大,好、嫌气纤解菌数量在1350～1725m~3/hm~2的灌水量下最大。在季节变化方面,各生理类群差异比较大。 3 耕作方式和灌水量对春小麦土壤线虫数量的影响 耕作方式对土壤线虫总数影响不大。随着灌水量的增加,线虫总数也增加,但秸秆还田中增加较快。大多处理土壤线虫总数在整个小麦生长季节呈单峰曲线,在抽穗期最大。植物寄生线虫的数量大于非寄生线虫。寄生线虫在常规中最多,免耕中次之,秸秆还田中最少;而非寄生线虫在秸秆还田中最多,免耕次之,常规最少。生长季节非寄生线虫的群体动态变化与寄生线虫的群体动态变化具有相反的变化趋势。同一季节土壤寄生线虫的种群数量在各处理之间差异比较明显,但在季节变化方面,表现为优势种群不变或次优势种群变为优势种群。 4 耕作方式和灌水量对小麦根病发生的影响 小麦根病发病率表现为常规>免耕>秸秆还田。在设定的灌水范围之内,小麦根病的发病率呈“V”型曲线,在灌水量1350m~3/hm~2时发病最轻。抽穗期小麦根病发病率平均更多还原

【Abstract】 The influence of straw mulching and saving on water on the numbers of soil fungi, bacteria, actinomycetes, physiological flora of microorganisms , soil nematodes and root diseases of spring wheat was studied in this paper. The results are as follows:(1) The influence of tillage treatments and irrigation on the numbers of soil fungi, bacteria and actinomycetes of spring wheat The numbers of three microorganisms were straw returned to field>no-tillage>conventional tillage, the numbers in straw returned to field were double to treble in conventional tillage, and the numbers in no-tillage were below double in conventional tillage. With increasing of irrigation quantity, the numbers of fungi reduced, the numbers of bacteria and actinomycetes increased in the beganing and reduced then, and the numbers were the most when irrigation quantity was 1350~1725m~3/hm~2 , but irrigation quantity did hardly influence numbers of bacteria. The numbers of these three microorganisms were a peak at dynamics of season, the numbers of fungi and actinomycetes were the most on heading stages and the least after harvest, but the numbers of bacteria were the most on jointing stages. Dominant genus of fungi was Fusarium in almost all statements and dominant species and genus of bacteria were WJ1 and WJ2, but their secondary species and genus were different.(2) The influence of tillage treatments and irrigation on the numbers of physiological flora of soil microorganisms of spring wheat The numbers of bacillus, nitrifying bacteria, aerobe azotobacter and aerobe cellullolytie were straw returned to field>no-tillage>conventional tillage, the numbers in straw returned to field were double to treble in conventional tillage and the numbers in no-tillage were below double in conventional tillage. The mumbers of denitrify bacteria, oligotrophic azotobacter and oligotrophic cellulolytie were no-tillage> straw returned to field> conventional tillage, the numbers of denitrify bacteria in straw returned to field and no-tillage were double to treble in conventional tillage and the numbers of oligotrophic cellulolytie and oligotrophic azotobacter were below double. With increasing of irrigation quantity, the numbers of nitrifying bacteria reduced and denitrify bacteria increased, the numbers ofbacillus, aerobe and oligotrophic azotobacter were the most when irrigation quantity was 975-1350m3/hm2, the numbers of aerobe and oligotrophic cellulolytic were the most when irrigation quantity was 1350-1725 m3/hm2. Physiological flora of soil microorganisms were different at dynamics of season.(3) The influence of tillage treatments and irrigation on the numbers of soil nematodes of spring wheat Patterns of tillage did hardly influence the numbers of nematodes. With increasing of irrigation quantity, the numbers of nematodes increased and change was quick in straw returned to field. The numbers of soil nematodes were a peak during wheat growing in almost all treatments and the numbers were the most on heading stages. The numbers of plant parasitic nematodes were more than non-parasitic nematodes in all treatments. The numbers of parasitic nematodes were conventional tillage>no-tillage>straw returned to field, but the numbers of non-parasitic nematodes were straw returned to field>no-tillage>conventional tillage. The numbers of parasitic nematodes and non- parasitic nematodes were reverse during wheat growing. Soil parasitic nematodes were different in different treatments at same season, but its dominant species and genus were same or secondary species and genus became dominant species and genus at dynamics of season.(4) The influence of tillage treatments and irrigation on wheat root diseases Incidence rates of wheat root diseases were conventional tillage>no-tillage>straw returned to field. With increasing of irrigation quantity, incidence rates were "V" and incidence rates were the least when irrigation quantity was 1350m3/hm2. Incidence rates on heading stages were about double on jointing stages. There were 1500 numbers and 1099 isolates and incidence was 73.27 percent on jointing stage. There were 1500 numbers and 1113 isolates and incidence was 74.20 percent on heading stage, pathogens had Bipolaris sorokiniana , Fusarium graminearum Schw , Fusarium oxysporum Schlecht and Fusarium culmorum in all treatments. Percents of these pathogens were different on jointing stages, however, percent of Bipolaris sorokiniana was the most in all treatments on heading stages.In all, considering fertilizing the soil and preventing disease and nematodes, the best treatment is straw returned to field and irrigation quantity is 1350 m3/hm2.更多还原