The Alleviation Effect and Productivity Enhancement Mechanism of Organic-Inorganic Composite Soil Conditioner on the Compound Harm of Oilseed Rape Feed in Sandy Soil in Arid Areas

The organic-inorganic composite polymer amendment (SAP) can be an effective way to enhance the stress resistance of sand crops in arid areas and increase productivity. The sandy soil in arid areas lacks water and fertilizer retention, and suffers from compound salt damage, which restricts crop growth and leads to insufficient nutrient absorption and weak stress resistance. In addition, the existing amendments have high costs and poor net benefits, which cannot meet the needs of local agricultural development. Therefore, there is an urgent need for low-cost and efficient soil improvement solutions. This study proposes a new improvement plan for organic-inorganic composite soil conditioner (SAP) to address the compound salt damage problem faced by rapeseed feed in sandy soils in arid areas. The study investigated the six treatment methods were compared through field experiments(CK:Organic fertilizer+chemical fertilizer; T1:Organic fertilizer+ chemical fertilizer+SAP;T2: Organic fertilizer+chemical fertilizer+PI humic acid type; T3: Organic fertilizer+chemical fertilizer+PII concave convex rod type; T4: Organic fertilizer+chemical fertilizer+PI+PII; HF: The effect of single application of chemical fertilizer)on nutrient absorption, physiological characteristics, yield and quality of rapeseed for feed.The results showed that the combination of organic-inorganic composite SAP, PⅠ, PⅡ, and PⅠ+PⅡ alleviated salt damage in sandy soil and increased nutrient content in various organs of crops. Analysis shows that composite SAP treatment performs the best. At the same time, (1)Salt damage alleviation: Compound conditioners increased root K+ content by 57.14-63.09%, decreased Na+ content by 60.16%, and significantly improved K+/Na+ratio (p<0.05); (2)Physiological improvement: The total chlorophyll content (TCC) increased by 86.85%, the highest SOD/POD enzyme activity increased by 161.58%, and the dry matter accumulation increased by 376.8%; (3)Yield and quality: T1 treatment increased yield by 148.32%, increased stem and leaf crude protein content by 86.05%, and reduced crude fiber by 43.59%; (4)Economic benefits: The net profit (NR) of SAP treatment reached 197.62 dollars per hectare, significantly better than other treatments (p<0.05).The comprehensive evaluation found that organic-inorganic composite SAP conditioners can synergistically improve the yield and quality of rapeseed feed in sandy areas by improving soil aggregation structure, enhancing antioxidant enzyme activity and photosynthetic efficiency, providing an economically effective solution for sustainable agricultural development in arid regions.