不同生态恢复措施下宁夏黄土丘陵典型草原土壤质量评价

为了研究生态恢复措施对草原土壤性状和土壤质量的影响,2016年在宁夏黄土高原丘陵区典型草原,以放牧草地(FM)为对照,研究了封育(FY)、水平沟(SP)和鱼鳞坑(YL)3种恢复措施对0～40 cm土壤理化性质和生物学特性的影响,评价了各措施下的土壤质量.结果表明:1)FM土壤容重最高,土壤黏粒含量、田间持水量和总孔隙度较低;FY、SP和YL措施间土壤物理性质差异不显著(P＞0.05).2)土壤有机质、全氮和速效氮以FY最高,SP和YL较低;全磷与速效钾含量以FM最高,SP最低.3)土壤蔗糖酶和脲酶活性呈FY＞SP＞YL＞FM;蛋白酶和磷酸酶呈FY草地最高,YL最低;细菌、放线菌和真菌在各处理间变化各异,微生物总量呈FY＞FM≈SP＞YL,但微生物生物量碳、氮呈FY＞YL≈SP＞FM(P＜0.05):土壤因子间存在一定的相关性.4)隶属函数结合因子分析法评价的土壤质量综合得分为FY＞SP＞FM＞YL.因此封育是最有利于研究区退化草地土壤质量恢复的措施,研究结果可以为宁夏典型草原生态建设提供理论基础.

Soil quality assessment under different ecological restoration measures in typical steppe in loess hilly area in Ningxia

In this paper,the experiment area is dry and prone to soil erosion,in order to stop slope runoff and promote rapid vegetation restoration,a restoration program was implemented.So it is significant for grassland ecological construction to study on the effects of ecological restoration measures on soil properties and soil quality.A study had been done to investigate the different of 0-40 cm soil depth of soil properties and assessment of soil quality under different restoration measures in typical steppe grassland in Ningxia.We selected the sites that has been subject to enclosure(FY),contour trench(SP),fish-scale pits(YL),which were implement in 2001 and grazed(FM) (as a reference,traditional grazing with some supplement) grassland.The results showed that:1) Soil bulk density of grazing grassland was the highest (P ＜0.05) whereas the soil clay content,field water holding capacity and total porosity were the lowest (P＜0.05),and there was no significant difference (P ＞ 0.05) in soil physical properties between enclosure,contour trench,and fish-scale pits grassland.2) Soil organic matter and total nitrogen were the highest (P ＜ 0.05) in enclosure grassland,followed by grazed grassland,and the lowest in contour trench.The content of total phosphorus was higher (P =0.05) in grazed and enclosure grassland,but was the lowest (P ＜ 0.05) in contour trench grassland.The available K content was the highest in grazed grassland the lowest in fish-scale pits grassland (P＜0.05).The content of available N was highest in enclosure grassland but lowest in contour trench grassland which were 161.75 mg/kg and 77.17 mg/kg respectively (P＜0.05).3) Soil sucrase and urease activity showed FY＞SP＞YL＞FM;protease and phosphatase activity both showed the highest (P ＜0.05) in enclosure grassland and the lowest (P ＜0.05) in the fish-scale pits grassland;the bacteria,actinomycetes and fungi were varied in each treatment;the amount of microorganisms showed FY＞FM≈SP＞YL whereas microbial biomass carbon and nitrogen showed FY＞YL≈SP＞FM (P＜0.05).4).As a whole,soil bulk density was negatively correlated with other indexes,and negatively correlated with clay content,field water holding capacity,total porosity,sucrase activity,urease activity,microbial biomass carbon and microbial biomass nitrogen (P＜0.01).There was a significant positive correlation between soil organic matter,total nitrogen and available nitrogen (P＜0.01) and the correlation between soil enzyme activity and soil microbial population (P＜0.05).Soil capillary porosity (except soil microbial biomass nitrogen) and available potassium were not correlated with other indexes (P＞0.05).5) The comprehensive score of soil quality evaluated by the membership function factor analysis method was:enclosure＞ grazed＞ contour trench＞fish-scale pits grassland.In summary,the enclosure grassland was more conducive to the restoration of typical grassland.Based on the study of the effects of enclosure,contour trench and fish-scale pits on the soil physical and chemical properties and biological traits,the membership quality of soil under different restoration measures was evaluated by membership function and factor analysis and can provide the basis for the ecological construction of typical grassland in Ningxia.The results showed that the enclosure was the most beneficial to the restoration of soil quality in degraded grassland in the study area.