不同土地利用方式下的蚯蚓种群特征及其与土壤生物肥力的关系

采用样方法对华北平原(河北曲周)盐渍化改造区7种土地利用方式下的蚯蚓种群进行详细调查,并通过培养实验研究了蚯蚓种群特征对若干土壤生物学指标的影响。结果表明:(1)在7种土地利用调查样地中共存在蚯蚓有3个科,5个属,5个种,其中赤子爱胜蚓(Eisenia fetida)占调查样地总个体数的60%以上,梯形流蚓(Aporrectodea trapezoides)和赤子爱胜蚓两个种在本地区广泛分布,样点出现频率分别为74%和44%,为该地区的优势种;(2)不同土地利用方式的蚯蚓种群密度及生物量变化趋势是:庭院菜地>直立免耕>清茬免耕>商品菜地>传统玉米地>果园>原貌地。其中庭院菜地蚯蚓种群的平均密度和生物量分别达到272 Ind.m-2和68.04gm-2;(3)蚯蚓种群密度和物种数等种群特征与土壤基础呼吸强度、微生物生物量碳含量成显著正相关(p<0.01),与土壤基础呼吸商成显著负相关(p<0.01);(4)不同土地利用方式下,蚯蚓的种群密度、生物量等种群特征对土壤中微生物群落的影响作用显著。蚯蚓生物量越大、种群越丰富的土壤有机质、氮、磷、钾等有效成分越高,反之则相反。室内培养实验表明,随着蚯蚓个体数量增加土壤原生动物总丰度、微生物生物量碳、氮也存在升高的趋势,与用土壤生物学特性指标及土壤化学特性指标评价的结果基本一致。

Earthworm population characteristics and their relationships with soil biological fertility under different land-use types in Quzhou County

Field surveys were carried out to investigate earthworm species in soils in 7 land-use types in salinity transforming region of Quzhou Country, Hebei Province and indoor incubation was done to study influences of earthworm population to soil biological parameters. Results show that (1) 5 species of earthworms were found, belonging to 5 genera and 3 families, with Eisenia fetida in dominance over 60% in number of individuals, and two species of Aporrectodea trapezoides and Eisenia fetida were widely distributed in this area, the present frequency in samples were 74% and 44% respectively, as the dominant species; (2) the order of earthworm population density and biomass change tendency in different land use types was : vegetable garden > vertical no-tillage > clean-stubble no-tillage > market vegetable plot > traditional corn land > orchard > abandoned land. The earthworm average population density and biomass were highest was in vegetable garden, achieving 272 Ind. m^-2 and 68.04 g m^-2 respectively; (3) Among the relationships between earthworm population characteristics and biological properties of soils the earthworm population density and the species number were positively correlated with soil basal respiration and microbial biomass carbon content significantly (p< 0.01 ), but soil basal respiration quotient existed significantly negative correlation (p< 0.01 ); (4) the effects of earthworm population density and biomass on soil microbial communities were significant. The greater the earthworm biomass and population, the higher the contents of soil organic matter, available nitrogen, available phosphorus, available potassium, and conversely contrary. Moreover the lab experiment also indicates that soil protozoa, microbial carbon, and microbial nitrogen tended to increase with the rise of the number of earthworm individuals. The characteristics of earthworm population can also be used as indicators in evaluating soil biological fertility, just like soil biological indicators and soil chemical indicators.