Cement kiln dust (CKD) and digestate for improving soil quality and crop yield and reducing greenhouse gas emissions

工业生产过程会产生大量的副产品，这些副产品通常被当作废物处理。在堆填区处理这类副产品既昂贵又不环保。许多工业废物类型可以回收或有益地利用。水泥工业产生的水泥窑粉尘（CKD）和沼气生产过程产生的沼液就是两种这样的工业副产品。加拿大水泥行业每年产生约67万吨CKD。CKD含有钙（Ca）、镁和硫等营养物质，是一种碱性物质，可用于中和酸性土壤的pH。消化液具有较高的可溶性有机物和氮含量，当它施用于土壤时，一氧化二氮的排放量可能会增加。然而，在加拿大的农田中，还没有关于单独或与消化剂联合使用CKD的土壤肥力或农艺效益的研究。研究小组将与工业合作伙伴（Norstar Industries Ltd）合作开发一个项目，研究在土壤pH值较低的灰色Luvisol地区，在小麦-油菜轮作中，CKD、消化液和腐植酸产品对土壤特性、温室气体排放、作物产量和质量的影响。评估的土壤特性包括土壤容重、全氮、磷(P)和钾(K)含量、有效氮磷钾和钙、pH值和电导率、总碳(C)、有机和无机（如果有的话）和氮，以及有机C的轻组分，溶解有机C和氮。还将评估处理对土壤和作物中可提取重金属含量的影响，以评估重金属污染的潜在风险。这项为期四年的研究将培养1名博士生、2名兼职博士后和4名本科生研究助理。研究小组和伙伴组织将共同努力，将研究成果传播给全国各地的农民，特别是加拿大西部的农民，并为CKD和消化系统的适当管理提供政策投入。

Industrial processes can produce a large quantity of by-products that are often treated as wastes. The disposal of such by-products in landfills can be costly and is environmentally unfriendly. Many industrial waste types can be recycled or beneficially used. Cement kiln dust (CKD) from the cement industry and digestate from the biogas production process are two such industrial by-products. The Canadian cement industry generates about 670,000 tonnes of CKD annually. The CKD contains nutrients such as calcium (Ca), magnesium and sulfur and is a material with an alkaline pH and can be used to neutralize the pH of acidic soils. The digestate has high soluble organic matter and nitrogen (N) content, and when it is applied to the soil, nitrous oxide emissions may increase. However, there has been no study on the soil fertility or agronomic benefits of the application of CKD alone or in combination with digestate in croplands in Canada. The research team will collaborate with the industrial partner (Norstar Industries Ltd) to develop a project to study the effect of CKD, digestate and a humic acid product on soil properties, greenhouse gas emissions, and crop yield and quality in a wheat-canola rotation in a Gray Luvisol that has low soil pH. Soil properties to be assessed include soil bulk density, total N, phosphorus (P) and potassium (K) contents, available NPK and Ca, pH and electrical conductivity, total carbon (C, both organic and inorganic, if any) and N, and the light fraction of organic C, and dissolved organic C and N. The effect of the treatments on extractable heavy metal contents in the soil and crop will also be assessed to evaluate the potential risk of heavy metal contamination. This four-year study will train one PhD student, two part-time postdoctoral fellows and four undergraduate research assistants. The research team and the partner organization will work together to disseminate the research findings to farmers across the country, in western Canada in particular, and provide policy input for the proper management of CKD and digestate.