渭北旱塬区不同植被恢复模式对土壤团聚体与微生物量的影响

发布时间：2018-04-05 19:07

本文选题：渭北旱塬区　切入点：植被恢复模式　出处：《西北农林科技大学》2015年硕士论文

【摘要】：本文以渭北旱塬区2种典型植被恢复模式(紫花苜蓿人工草地与刺槐人工林)为研究对象,天然草地与农用地为对照,采用干筛法将土壤筛分为0.25 mm、0.25~1 mm、1~2 mm与2 mm等粒级,研究不同植被恢复模式对土壤理化性质、土壤微生物量、土壤团聚体微生物量的影响。研究结果如下:1、紫花苜蓿人工草地与刺槐人工林可以改善土壤质量,降低土壤容重。不同植被恢复模式各层土壤容重为1.21~1.38 g·cm-3,不同植被恢复模式对土壤容重的影响在0~20cm层差异不显著,而在20~40 cm土层显著差异(P0.05)。不同植被类型间总体上为:苜蓿草地农用地天然草地刺槐林地。建植苜蓿与刺槐土壤含水量均会随着恢复年限的增加而减少,说明渭北旱塬区水分是制约植被恢复的重要限制因子,因此对渭北旱塬区生态环境的综合治理应充分重视水分供应。2、土壤团聚体含量随粒径的变化呈现出“V”字形变化:0.25 mm的微团聚体与2mm的团聚体含量高,而中间的粒级比例低。种植苜蓿、刺槐等可以显著减少土壤微团聚体,促进土壤团聚。种植苜蓿、刺槐对土壤浅表层的团聚作用优于天然草地与农用地。随土层深度的增加大团聚体含量趋向稳定。3、不同年限的苜蓿与刺槐植被恢复模式可以明显改善土壤质量,提高土壤肥力。土壤有机质与全氮,全磷与速效磷,速效磷与有效钾均极显著相关(P0.01);微生物量碳与土壤有机质、全氮及微生物物量氮与全氮显著正相关(P0.05)。各土层微生物量碳、氮在不同植被恢复模式间都达到极显著相关的水平(P0.01)。土壤微生物量碳、氮与有机质、全氮相比较,可以更灵敏地指示土壤质量变化,因此,土壤微生物生物量在渭北旱塬区的植被恢复成效评价中应引起一定的重视。4、不同生长年限的苜蓿草地土壤质量随着年限的增长先增长后下降,苜蓿11年整体恢复效果最佳。不同恢复年限刺槐人工林整体土壤质量随年限增加呈现先增长后下降趋势,刺槐21年恢复效果最佳。渭北旱塬区紫花苜蓿人工草地在恢复11年后应当进行合理利用或进行其他人工干预以延长草地使用寿命;人工刺槐林建植21年左右也应当进行合理干预或利用。
[Abstract]:In this paper, two typical vegetation restoration models (alfalfa artificial grassland and Robinia pseudoacacia plantation) in Weibei dryland were studied, and natural grassland and agricultural land were compared. The soil was sifted with dry sieve method to divide the soil into 0.251mm and 2mm in grain size.The effects of different vegetation restoration models on soil physical and chemical properties, soil microbial biomass and soil aggregate microbial biomass were studied.The results are as follows: 1. Alfalfa artificial grassland and Robinia pseudoacacia plantation can improve soil quality and reduce soil bulk density.The soil bulk density of different vegetation restoration models was 1.21 ~ 1.38 g cm ~ (-3). The effect of different vegetation restoration models on soil bulk density was not significant in 0~20cm layer, but significantly different in 20 ~ 40 cm soil layer.The different vegetation types are: alfalfa grassland agricultural land natural grassland Robinia pseudoacacia forest land.The soil moisture content of alfalfa and Robinia pseudoacacia decreased with the increase of restoration years, indicating that water is an important limiting factor for vegetation restoration in Weibei dryland.Therefore, the comprehensive management of ecological environment in Weibei dryland should pay more attention to water supply. The content of soil aggregate with the change of particle size shows a high content of "V" shape microaggregate and a high content of 2mm aggregate, but the ratio of middle grain size is low.Planting alfalfa and Robinia pseudoacacia can significantly reduce soil microaggregates and promote soil aggregation.The agglomeration effect of Robinia pseudoacacia on shallow surface layer of alfalfa was better than that of natural grassland and agricultural land.The content of large aggregates tended to be stable with the increase of soil depth. The restoration model of alfalfa and Robinia pseudoacacia with different years could improve soil quality and soil fertility significantly.Soil organic matter and total nitrogen, total phosphorus and available phosphorus, available phosphorus and available potassium were significantly correlated with P0.01N, microbial biomass carbon and soil organic matter, total nitrogen and microbial biomass nitrogen were positively correlated with total nitrogen.Microbial biomass carbon and nitrogen in different soil layers were significantly correlated with each other in different vegetation restoration models (P 0.01).Soil microbial biomass carbon and nitrogen, compared with organic matter and total nitrogen, can more sensitively indicate changes in soil quality.Soil microbial biomass should be paid attention to in the evaluation of vegetation restoration effect in Weibei arid plateau. The soil quality of alfalfa grassland with different growth years increased first and then decreased with the increase of the number of years, and the overall recovery effect of alfalfa for 11 years was the best.The soil quality of Robinia pseudoacacia plantation with different restoration years increased first and then decreased with the increase of the number of years, and the effect of 21 years of Robinia pseudoacacia restoration was the best.After 11 years of restoration, alfalfa artificial grassland in Weibei dryland should be rationally utilized or other artificial intervention to prolong the service life of grassland, and artificial Robinia pseudoacacia forest should be established for 21 years or so with reasonable intervention or utilization.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154.3

【共引文献】