大棚种植对农业土壤环境的胁迫

Influence of Greenhouse Cultivation on Agricultural Soil Environment

为研究集约化生产方式对农田环境的影响,实验测定了河北省邯郸市永年县的大田和大棚两种不同种植方式下,土壤微生物、重金属污染和有机磷农药残留的情况。本研究分别使用平板计数法和氯仿熏蒸法测定土壤中微生物区系及其生物碳量;采用原子吸收分光光度法测定土壤和植物体内重金属含量;采用气相色谱质谱法测定土壤和植物体内有机磷农药残留量。结果显示,随大棚使用年份的增加,土壤中的细菌和放线菌数量显著增加,而真菌数量显著减少,即细菌真菌比上升,说明大棚中农田微生物区系结构仍处于较好的状态;但同时微生物碳量明显减少,间接反映大棚土壤养分压力的增加。污染物积累方面,大棚土壤中的重金属积累和有机磷农药残留均与大田情况相当。因此本研究认为,短期(20a)内的大棚种植对农业土壤环境并未产生严重的胁迫。另外,微生物作为农田土壤生态系统中重要的因子,是土壤质量评价中较灵敏的指标。

To study the influence of greenhouse cultivation on agriculture soil environment, the samples of soils and plants were collected from open fields and greenhouses in Hebei Province and were examined in three aspects of microbes, heavy metals and organophosphorus pesticides. Amounts of microorganism and structure of microbial community were examined with the method of diluted plate counting, and the microbial biomass of carbon was determined with the chloroform-fumigation and incubation method. Contents of heavy metals and residues of organophosphorus pesticides in soils and plants were also examined by atomic absorption spectrophotometry and GS-MS, respectively. The results showed a notable increase of bacteria and actinomycetes and a significant decrease of fungi in greenhouses, that is, the ratio of bacteria to fungi increased, which meant that the structure of the microbial community was still in a good situation. Meanwhile, the microbial biomass reduced along with the usage of greenhouses, which might indirectly reflect the increase of nutrients pressure. Accumulation of heavy metals and organophosphorus pesticides were not found in the greenhouses. Therefore, the study considered that short-term （20 years） intensive agricultural cultivation in greenhouses might not cause serious impact on the soil environment. The microbes in the agriculture soil system showed a sensitive response to the change of soil quality, which would be used as a good indicator of soil environment assessment.