离石区不同种植年限大棚土壤养分累积特征

Studyon Soil Nutrient Accumulationin of Greeenhousein Different Plangting Yearsin Lishi

研究离石区蔬菜大棚土壤随种植年限的变化趋势,为指导当地菜农的施肥与土壤管理.选取离石区露天农田（对照,CK）及种植年限分别为1、2、3、5、15、20年的表层土壤（0～20 cm）作为供试材料,分析土壤主要理化性质指标随种植年限的变化规律.土壤pH随大棚种植年限的增加而逐渐下降;电导率（EC）与pH值呈相反趋势,5年大棚土壤的电导率（0.53 mS/cm）已超过作物生育障碍临界点（EC＞0.50 mS/cm）,20年大棚土壤的电导率（1.03 mS/cm）,接近黄瓜的生育障碍临界点（1.2 mS/cm）;土壤有机质和速效养分的含量均随种植年限的增加而增加,且氮磷钾富集现象较为明显;当大棚使用到一定年限（5年）时,土壤有机质、全氮及碱解氮含量趋于稳定状态,随种植年限的增加其变化的幅度减小.施肥可能是导致蔬菜大棚土壤养分富集的重要原因.因此,建议当地提高农户土肥管理技术,严格控制化肥施用量.

The study was conducted to get a fertilization and soil management as a guide for local farmers by researching the variation trends of soil fertility with the extension of planting years in greenhouse. Soil samples were taken from open field soils and greenhouse topsoils （0-20 cm） with different planting years in Lishi region, and analyzed the soil accumulation characteristics indicators of the main physical and chemical property indicators. The greenhouse soil pH was gradually reducing with the increasing planting years. Electrical conductivity and pH were opposite trend, 5 years of greenhouse soil electrical conductivity （0.53 mS/era） had exceeded the critical point of crop growth disorders （EC〉0.50 mS/cm）, 20 years of greenhouse soil electrical conductivity（1.03 mS/cm） close to the critical point of cucumber growth disorders （1.2 mS/cm）. Soil organic matter and available nutrient contents were increasing with the increasing planting years, the enrichment phenomenon of N, P, K was more obvious. When using greenhouse soils to a certain age （5 years）, soil organic matter, total nitrogen and nutrient nitrogen contents trended to be stable state, and their variation amplitude changes was unobvious with the planting years. Fertilization may be an important cause of vegetable greenhouse soils nutrient enriched. Therefore, local farmers should be improved in soil and fertilizer management technology, reduced properly chemical fertilizers.