Feasibility of waste tuff powder as a soil conditioner for coastal saline soil(凝灰岩石粉基调理剂对滨海盐碱地改良效果研究)

Abstract

The tuff mining process produces huge amounts of associated waste stone powder, and the disposal of these powders has been restricting the deep development of mines. This study prepared a new type of saline soil conditioner based on tuff powder and setting different ratios of mussel shells, biochar, humic acid and other materials, in order to explore new ways of resource utilisation of waste tuff powder. Comparative tests were carried out using potting and condition control methods to investigate the effects of different ratios of conditioners on the physicochemical properties of soil and the growth and development of Brassica campestris L. The results showed that the addition of pure tuff powder could reduce soil pH. However, the pure tuff powder was not favourable for organic matter and nitrogen and phosphorus uptake. At the same time, the sodium adsorption ratio and exchangeable sodium content of soil increased, which aggravated soil salinity with the high addition of pure rock flour (>40 g·kg-1). Compared with the control group (CK), the group with better pH improvement effect in different ratios of soil conditioners could reduce it by about 0.66. And the soil hydrolysable nitrogen and fast-acting potassium content could increase 41.15% and 10.44% respectively. It also had a significant effect on crop growth, with the height of Brassica campestris L. increased by 35.59%. Combining with the data of soil physicochemical indexes, the optimum amount of tuff powder was 50 g. It was determined that the ratio of a better conditioning effect for tuff powder, mussel shells after carbonisation, crude mussel shells, biochar and humic acid was 50, 3, 10, 5 and 5 g respectively. The research and development of waste tuff powder-based conditioner can provide new ideas for the improvement of coastal saline-alkali soil and a new way for the resource utilization of tuff powder.(在石料开采过程中，凝灰岩会产生巨量伴生性废弃石粉，影响矿山的绿色可持续发展。为探讨废弃凝灰岩石粉的资源化利用途径，以石粉为基础，辅以不同配比的贻贝壳、生物炭、腐殖酸等，制备了凝灰岩石粉基调理剂。采用单因素控制法对植物和土壤进行对比试验，探究不同配比调理剂对土壤理化性质及小白菜生长发育的影响。结果显示：纯石粉可调节土壤pH，但添加过多（≥200 g）不利于土壤有机质及氮、磷的释放，同时，纯石粉会促进土壤的钠吸附比和交换性钠增加，加重土壤盐害。凝灰岩石粉基调理剂可有效弥补纯石粉的不足，相较对照组（CK），水解性氮、速效钾质量浓度分别提高了41.15%，10.44%，不同配比土壤调理剂中pH改良效果较好组可使其降低约0.66；同时本调理剂对作物生长也有明显促进作用，小白菜的株高较CK最多可提升35.59%。综合土壤理化指标和作物生长指标，确定纯石粉最适添加量为50 g，凝灰岩石粉基调理剂最佳配方为50 g石粉+3 g碳化后贻贝壳+10 g粗贻贝壳+5 g生物炭+5 g腐殖酸。凝灰岩石粉基调理剂的研发可为滨海盐碱地的改良提供新思路，为废弃石粉的资源化利用提供新途径。)

Keywords

• soil conditioner(土壤调理剂)
• coastal saline soil(滨海盐碱土)
• tuff powder(凝灰岩石粉)
• soil physical and chemical properties(土壤理化性质)