园林绿地施用污泥堆肥对环境影响研究

园林绿地施用污泥(来源于天津纪庄子污水处理厂)堆肥的试验表明:径流和渗滤水中硝酸盐的增加是最主要的污染问题,但污泥堆肥用量控制在50t/hm2以内,不会对地面水和地下水产生不良影响?该厂污泥中的重金属和有机污染物亦不会对径流和渗滤水产生明显不良影响?      

Influence of compost amendment rate and level of compaction on the hydraulic functioning of soils

There has been widespread interest in using compost to improve the hydrologic functions of degraded soils at construction sites for reducing runoff and increasing infiltration. The objective of this study was to determine the effects of compost amendment rate on saturated hydraulic conductivity (K_s) and water retention in order to identify target compost rates for enhancing soil hydrologic functions. Samples were prepared with three soil textures (sandy loam, silt loam, and sandy clay loam), amended with compost at 0%, 10%, 20%, 30%, 40%, and 50%. All soils were tested at a porosity of 0.5 m³/m³, and the sandy loam was further tested at high (0.55 m³/m³) and low (0.4 m³/m³) porosities. The K_s and water retention data were then used to model infiltration with HYDRUS-1D. With increasing compost amendment rate, K_s and water retention of the mixtures generally increased at the medium porosity level, with more compost needed in heavier soils. As porosity decreased in the sandy loam soil, the amount of compost needed to improve K_s rose from 20% to 50%. Water distribution in pore fractions (gravitational, plant-available, and unavailable water) depended on texture, with only the highest compost rates increasing plant-available water in one soil. Results suggest soil texture should be taken into consideration when choosing a compost rate in order to achieve soil improvement goals. Hydrologic benefits may be limited even at a high rate of compost amendment if soil is compacted.     

不同配比农业废物堆肥过程中堆肥的阴阳离子和大分子对种子发芽的影响

为揭示不同配比农业废物堆肥过程中阴阳离子和大分子对植物毒性的影响机理，开展了以鸡粪和猪粪为主料，稻草秸秆为辅料的条垛堆肥试验，设置的试验处理包括：等质量的鸡粪+稻草秸秆+包菜（1∶1∶1）处理（T1）、鸡粪+稻草秸秆（1∶1）处理（T2）、大量猪粪+少量稻草秸秆（85∶15）处理（T3）.测定了各处理的堆温、堆肥的水溶性无机阴阳离子和有机大分子变化，以及对大白菜（Brassica rapa L.）和水堇（Lepidium sativum. L.）种子发芽指数（Germination Index， GI）等指标变化的影响.试验结果表明，T3处理堆肥的高温（>55 ℃）持续期最长，杀灭病原微生物和杂草种子的能力最好，且其堆肥的Cl^-、SO42-、K⁺、Na⁺、Ca²⁺和Mg²⁺浓度最低；T2处理堆肥的NH4+ 浓度最低.T1和T2处理堆肥过程中堆肥的脂肪烃可转化为稳定的芳香烃.T3处理堆肥对大白菜和水堇的种子发芽指数大于80%.堆肥中抑制种子发芽的阴阳离子及大分子浓度分别为：Ca²⁺浓度>0.98 mmol·L^-1，Mg²⁺浓度>0.92 mmol·L^-1，NH4+浓度均>5.75 mmol·L^-1，芳香C/多糖比值>0.33，羧基C/多糖比值>0.30.堆肥中脂肪族大分子增加、多糖类大分子减少可抑制种子发芽.综上所述，猪粪与稻草秸秆的质量配比为85∶15、初始C/N比为25、初始水分含量为60%、 堆肥期周为35 d是条垛式堆肥处理猪粪和稻草秸秆的最佳工艺参数.大白菜比水堇种子更能准确反映农业废物堆肥的植物毒性.本研究可为优化不同畜禽粪便与农作物秸秆的条垛堆肥工艺参数、减少土地利用的风险提供重要的决策支持.