天然钠基膨润土菌渣复合材料对提高沙土保水保肥效应的影响

中国西北地区沙漠边缘地带存在干旱缺水、土壤沙化程度高、漏水漏肥严重等问题，严重影响了植物正常生长，制约了农业和林果业可持续发展。该研究探究天然钠基膨润土菌渣复合材料对沙土保水保肥性能的影响。通过室内模拟试验，采用茶袋法及土柱模拟法，研究不同用量膨润土P（3%、5%、7%、9%），不同膨润土菌渣复合材料JF（膨润土+菌渣+腐植酸）、JA（膨润土+菌渣+氨基酸）、JN（膨润土+菌渣+牛粪）及不同主材比例（膨润土与菌渣比分别为1:2、1:2.5、1:3、1:3.5）对改善沙土漏水漏肥的效果。结果表明，JF、JA及JN组处理较P组处理可更大程度地提高沙土吸水倍数及持水性能；土柱淋溶条件下，P组处理可明显降低沙土水分累积渗漏量达18.00%～26.17%，氮素累积渗漏量达11.58%～27.22%，钾素累积渗漏量达2.82%～7.78%；JF1、JA1及JN1处理可明显降低沙土水分累积渗漏量达25.53%～30.31%，氮素累积渗漏量达25.66%～32.36%，钾素累积渗漏量达6.35%～10.73%），其中JF1处理降幅最大，且当膨润土用量为菌渣用量的一半，辅材为腐植酸时效果最佳，这也反映出菌渣及腐植酸的添加对膨润土提高沙土保水保肥性能具有明显的促进作用。试验表明在沙土中添加钠基膨润土菌渣复合材料可提高沙土保水保肥性能，特别是在减少氮素淋溶损失方面具有良好效果，研究结果能够为西北风沙区生态修复及乡村振兴提供策略和依据。

Impacts of natural sodium bentonite mushroom residue composite on improving water and fertilizer retention effect in sandy soil

The edge of the desert of Northwest China faces problems such as drought, water shortage, soil desertification, serious water leakage and fertilizer leakage, which seriously affect the normal growth of plants and restrict the sustainable development of agriculture and forest and fruit industry. In this study, indoor experiments were carried out to explore the effects of natural sodium bentonite mushroom residue composites on soil water and fertilizer retention performance. Teabag and soil column simulation method were used. Pure bentonite (P) and three treatments of composite materials were designed including bentonite-mushroom residue-humic acid composite (JF), bentonite-mushroom residue-amino acid composite (JA) and bentonite-mushroom residue-cow dung composite (JN). Each treatment of composite materials included four levels of bentonite-mushroom residue ratio of 1:2, 1:2.5, 1:3 and 1:3.5. For the treatment of P, four proportions of bentonite was designed including 0, 3.0%, 5.0%, 7.0% and 9.0%. For the JF, the humic acid accounted for 1.5%. For the JA, the amino acid accounted for 1.5%. For the JN, the dried cow dung accounted for 1.5%. The effects of water leakage and fertilizer leakage in sandy soil of each treatment were analyzed. The results showed that the treatments of group JF, JA, and JN improved the water absorption ratio and water holding capacity of sandy soil than that of the treatments of group P to a greater extent. Under the condition of soil column leaching, with the increase of the amount of bentonite (P), the cumulative leakage of water and nutrients showed a decreasing trend. When the amount of pure bentonite accounted for 3% to 9% of the total sandy soil, the cumulative leakage of water decreased by 18.00% to 26.17%. Among the cumulative leakage of nutrients, the cumulative leakage of nitrogen decreased by 11.58% to 27.22%. In addition, the cumulative leakage of potassium decreased by 2.82% to 7.78%, and the cumulative leakage of phosphorus decreased little. In the composites of JF, JA and JN, when the ratio of bentonite to mushroom residue was 1: 2, the cumulative leakage of water and nutrients decreased greatly. Among them, the water cumulative leakage decreased by 25.53% to 30.31%. The cumulative leakage of nitrogen was decreased by 25.66% to 32.36%. Besides, the potassium cumulative leakage decreased by 6.35% to 10.73%, and the phosphorus cumulative leakage rate decreased slightly. According to the results of this study, the decrease of JF1 treatment was the largest, indicating that the water and fertilizer retention effect is the best when the amount of bentonite is half of the amount of mushroom residue and the auxiliary material is humic acid. It also indicated that the addition of mushroom residue and humic acid could obviously promote the performance of sandy soil in water and fertilizer retention. The experimental results showed that the addition of natural sodium bentonite mushroom residue composite to sandy soil could improve the performance of water and fertilizer retention of sandy soil, especially in reducing the loss of nitrogen leaching. The results of this study can provide valuable information for the rational utilization of plant fibrous agricultural wastes, such as natural sodium bentonite and mushroom residue to improve the utilization rate of water and fertilizer in the agricultural and forestry planting areas of Northwest China.