为了研究草坪-土壤体系下施用沼肥对地下水氮的环境影响,在北京的气候条件下,采用地下参滤系统土柱试验装置年沼肥施氮量分别为20、60、100、140 g/(m2·a)和年化肥施氮量为20 g/(m2·a)5种条件下,对1m以下草坪土壤渗滤液中氨态氮、硝态氮和总氮浓度进行了测试,并分析不同用量沼肥氮对其的影响.结果表明:随着沼肥施氮量的增加,土壤渗滤液中氨态氮、硝态氮、总氮浓度升高.氮肥施用量为20 g/(m2·a),化肥处理渗滤液的氨态氮、硝态氮、总氮浓度高于沼肥.各处理氨态氮去除率均在99.8％以上；总氮去除率为86.7％～95.6％之间,沼肥施氮量为60 g/m2时,总氮去除率最高为95.6％.根据地下水环境质量标准(GB/T 14848-93),施氮量为20和60 g/(m2·a)时,渗滤液硝态氮均达到Ⅲ类水质标准；而施氮量为100和140 g/(m2·a)时,分别有10％和32.5％的监测样本超过Ⅲ类水质标准,且主要集中在7和8月份.该研究表明,以Ⅲ类水质硝态氮质量浓度20 mg/L为评价标准,年沼肥施氮量600 kg/(hm2·a)没有对地下水环境造成硝态氮的污染.%In order to study on the effect of biogas fertilizer application on nitrogen of groundwater in turf-soil system, under the climate condition of Beijing, contrast test was made with a soil column test device of subsurface infiltration system. Below 1 m soil depth, the concentration of NH/-N, NO3-N and total nitrogen in the turf-soil leachate were measured under the five conditions and effect of different biogas application on them was analyzed. The five conditions were that the annual application rate of nitrogen was 20,60,100,140 g/(m2a) in each biogas fertilizers and it was 20 g/m2 in the chemical fertilizer with above device. The results showed that the concentration of NH4+-N, NO3 -N, total nitrogen in Ihe soil leachate increased with rising of nitrogen dosage in biogas fertilizers. When nitrogen application was 20 g/m2 annually, the concentration of NH/-N, NO3 -N and total nitrogen in the soil leachate which was applied with chemical fertilizer was higher than that which was applied with biogas fertilizer. Ammonia nitrogen removal rates of all treatments were higher than 99.8% and total nitrogen removal rates of all treatments were 86.7%-95.6%. While nitrogen application of biogas fertilizer was 60 g/(m2·a), the highest total nitrogen removal rate was 95.6%. Based on the quality standard for groundwater (GB/T 14848-93), the NO3 ~N concentrations in soil leachate which nitrogen application of biogas fertilizer were 20 and 60 g/(m2-a) came up to water quality standards of category IE. When nitrogen application of biogas fertilizer were 100 and 140 g/(m2·a), NO3-N concentrations in soil leachate of 10% and 32.5% samples exceeded the water quality-standards of category III and it mainly occurred in June and August. The conclusion that 600 kg/(hm -a) nitrogen application of biogas fertilizer don't cause NO3--N pollution to groundwater based on evaluation criterion that mass concentration of NO3 -N is 20 mg/L( water quality standards of category Ⅲ) in leachate is arrived at.
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