污泥改性黄土合适配比及作物盆栽实验

黄土广泛分布于我国西北地区，其颗粒细小、结构疏松、易发生水土流失且营养缺乏，污泥的施入能够改善黄土理化性质，提高土壤养分。实验采用室内盆栽种植方法，研究不同比例污泥施入黄土对小麦、油菜生长情况及黄土理化性质的影响，为贫瘠的西北半干旱黄土地区城市污泥土地利用提供科学依据。结果表明，污泥施入明显提高了黄土有机质含量，改善了土壤的碱性环境，但是混合基质的重金属含量也相应增加，因此在实际利用过程中必须合理控制污泥施入比例，污泥干质量超过10%会不同程度延缓作物生长，1%~5%的污泥能够提高作物发芽率、缩短发芽时间、促进作物生长。由此说明，贫瘠黄土地区施入实验所用污泥的干质量5 250~26 400 kg·hm-2左右能够明显改善土壤种植条件，有望提高该地区小麦和油菜的产量。

Reasonable proportion of sludge modified loess for a pot experiment of crops

Loess is widely distributed in northwest China, made up of tiny particles with loose structure, and prone to soil erosion and poor nutritional conditions. The physicochemical properties and soil nutrients may be improved when sludge is applied to loess. This study used the indoor potted planting method to research plant growth and the physicochemical properties of loess when different proportions of sludge were applied to the loess, with the goal of providing a scientific basis for the land use of municipal sewage sludge in the barren and semi-arid loess areas. Results showed that sludge applied to loess increased the organic matter of the loess and improved the soil alkalinity. However, heavy metal concentrations also increased; therefore, the amount of applied sludge must be controlled during practical use to minimize heavy metal contamination. Plant growth was inhibited to different degrees when more than 10% mass of dry sludge was used; however, 1% to 5% of dry sludge increased the plant germination rate, shortened the germination time, and promoted plant growth. The amount of sludge applied to the nutrient-poor loess improved growing conditions from 5 250 to 26 400 kg·hm-2. This application is expected to increase the output of wheat and cole as well.