摘要
【目的】苹果园土壤肥力持续下降,禽畜废弃物肥源严重不足,施用植物源有机肥成为生产中改善果园土壤状况的重要措施之一。本试验利用BIOLOG微平板技术研究了盆栽条件下添加植物源有机物料及其腐殖化过程驱动因子对果园土壤微生物群落多样性的影响,探讨葡萄糖、尿素和蚯蚓在植物源有机物料向土壤碳库转化中的作用,为揭示果园土壤质量的演变机制提供参考。【方法】取苹果园0—20 cm土层土壤,与苹果枝条、玉米秸秆和果园杂草粉碎物混合,栽植2a生苹果砧木山定子幼苗,分别添加尿素、葡萄糖和蚯蚓,利用BIOLOG微平板技术进行土壤微生物群落多样性分析。不同处理的土壤浸提液在BIOLOG生态测试板中培养,取培养96 h时微平板光密度值进行多样性指数计算,分别用丰富度指数S表示被微生物群落利用的基质数量,多样性指数表示反应孔与对照孔光密度值之差和整块板总差的比值,均匀度指数E表示可培养微生物的种类均匀度,优势度指数Ds用于评估某些最常见种的优势度。对土壤微生物群落利用BIOLOG微平板中六类碳源(碳水化合物类、氨基酸类、羧酸类、多聚物类、芳香族类和胺类)的情况进行主成分分析,明确不同处理微生物对碳源利用能力的差异。【结果】有机物料种类、小分子有机物和蚯蚓数量均对平均吸光值(AWCD值)有显著影响,在培养0~24 h,玉米秸秆+葡萄糖+12条蚯蚓(T4)和果园杂草+葡萄糖(T9)处理的AWCD值明显高于其他处理,微生物群落的活性较强,碳源开始利用较早。24~96 h时,AWCD呈指数增长,120 h后趋于平缓,以玉米秸秆+葡萄糖+12条蚯蚓(T4)、苹果枝条+葡萄糖+6条蚯蚓(T2)、果园杂草+葡萄糖(T9)处理斜率最大,其次为玉米秸秆+尿素+6条蚯蚓(T6)和苹果枝条+尿素(T1)处理;小分子有机物种类对微生物群落丰富度指数(S)和优势度指数(Ds)的影响显著,丰富度指数(S)以苹果枝条+葡萄糖+6条蚯蚓(T2)最大,优势度指数(Ds)以玉米秸秆+葡萄糖+12条蚯蚓(T4)最大,各处理的多样性指数(H)和均一度指数(E)差异不显著;对碳源利用主成分起分异作用的主要是碳水化合物类和多聚物类。【结论】与秸秆和杂草处理相比,苹果枝条处理土壤微生物群落多样性较丰富,加入葡萄糖为土壤微生物提供可迅速利用的碳源,微生物功能多样性也显著增加;蚯蚓活动对微生物群落多样性的影响比葡萄糖小,尿素对微生物群落多样性的影响也较小,但同时添加尿素和葡萄糖有助于微生物多样性的增加。
Objectives As soil fertility in apple orchards is declined continuously and livestock waste organic manure sources are seriously inadequate, application of plant-derived organic manure is becoming one of important measures to improve orchard soil conditions. Effects of plant-derived organic matter and driving forces on soil microbial functional diversity in pot planted apple rootstock seedlings were studied by using the BIOLOG microplate technique. The functions of glucose, urea and earthworm in the plant-derived organic matter transformation process to soil carbon pool were explored, which could provide a reference for revealing evolution mechanism of orchard soil quality. [Methods]2a Malus baccata (L. ) Borkh seedlings were planted in apple orchard soils (0 -20 cm) mixed with chopped apple branches, corn stalks and orchard weeds. The urea, glucose and earthworms were added into the pots. The soil microbial community diversities were analyzed by the BIOLOG technique. Soil extracts of different treatments were cultured in BIOLOG ecological test plates. The diversity indexes were calculated using microplate optical density values at 96 h. Substrate richness (S) is the number of different substrates used by the community (counting all positive OD readings). Shannon’s diversity index is the ratio of the corrected absorbance value of each well to the sum of absorbance value of all wells. Substrate evenness (E) is a measure of the uniformity of activities across all substrates. Simpson’s Dominance indicates the dominance of certain species. The carbon substrate utilization differences of microbe were obtained by principal components analysis (PCA) of six carbon sources (carbohydrates, amino acids, carboxylic acids, polymers, aromatic and amines) in the BIOLOG microplates. [Results]The results show that the average well color development(AWCD) values are significantly affected by organic material types, small molecular organic compounds and numbers of earthworms. The AWCD values of the corn straw + glucose + 12 earthworms(T4) and the orchard weed with glucose(T9) are obviously higher than those of other treatments in the first 24 hour culture, and the activities of microbial communities are also higher and carbon sources are used earlier. The AWCD values show an exponential growth in the 24-96 hour culture, and then become flat after 120 hours. The treatments of the corn straw + glucose + 12 earthworms(T4), the apple branches + glucose + 6 earthworm (T2)and the orchard weed with glucose(T9) have the steepest slopes and the highest microbial activities, and secondly for the corn straw + urea + 6 earthworm(T6) and the apple branches with urea ( T1) treatments. The small molecular organic compounds have significant effects on the microbial community substrate richness(S) and Simpson’s dominance (Ds), and the substrate richness (S) is the highest under the apple branches + glucose + 6 earthworm(T2), while the Simpson’ s dominance(Ds) is the highest under the corn straw + glucose +12 earthworms(T4). The Shannon index(H) and Substrate evenness (E) between different treatments are not significantly different. It is found that the differentiations of soil microbial communities are mainly caused by carbohydrate and polymers carbon. [Conclusions]Compared with the straw and weeds treatments, the microbial diversity of the branches treatments is high. The glucose provides carbon sources which can be used rapidly by microbe, and the microbial functional diversity is significantly increased. The effect of earthworm activity on the microbial functional diversity is less compared with the glucose. The urea has little effects on the microbial functional diversity, while the combination of urea and glucose could improve the microbial diversity.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2014年第4期913-922,共10页
Journal of Plant Nutrition and Fertilizers
基金
农业部"948"项目(2012-Z4)
现代苹果产业技术体系建设项目(CARS-28)
国家自然科学基金(31171917)
公益性行业(农业)科研专项(201103005-01-04)资助
