甘蔗叶源腐植酸对罗汉果苗期生长、生理和土壤土质调控的效应OA

Aiming at the problem of sugarcane leaf utilization and soil degradation caused by excessive chemical fertilizer in Siraitia grosvenorii planting,a green fertilization strategy of replacing compound fertilizer with sugarcane leaf humic acid was proposed for the first time,and its synergistic effect on regulating the growth of Siraitia grosvenorii seedlings and soil quality was systematically explored.A gradient experiment was conducted and five treatments with different substitution levels were set up,namely the substitution of 20%compound fertilizer with sugarcane leaf humic acid(T1),the substitution of 40%compound fertilizer with sugarcane leaf humic acid(T2),the substitution of 60%compound fertilizer with sugarcane leaf humic acid(T3),the substitution of 80%compound fertilizer with sugarcane leaf humic acid(T4),and the substitution of 100%compound fertilizer with sugarcane leaf humic acid(T5).The application of compound fertilizer alone was set as the control group(CK).The comprehensive effects of substitution ratio on plant morphology,leaf physiology,soil available nutrients,and enzyme activity were evaluated.The results showed that:(1)Plant growth characteristics:The T4 treatment significantly promoted the growth of the plant height,leaf area,leaf length,leaf width,fresh leaf weight,and dry leaf weight of Siraitia grosvenorii,which increased by 103.9%,44.4%,45.8%,76%,74.6%,and 70.5%,respectively,compared with CK,and the morphology of the plants was optimized.(2)Physiological response of leaves:T3 and T4 treatments significantly increased the content of photosynthetic pigments in leaves,with T4 chlorophyll a,chlorophyll b,and carotenoids increasing by 28.8%,15.9%,and 159.0%,respectively,compared to CK,and simultaneously enhancing photosynthetic efficiency and stress resistance.T2 treatment significantly increased the soluble sugar content of leaves,T2-T5 treatments significantly increased the soluble protein content,while T3 and T4 treatments significantly reduced the proline content;T2-T4 treatment significantly enhanced the activities of peroxidase and catalase,while T4 treatment significantly increased the activity of superoxide dismutase(+97%).However,T5 treatment had significantly lower leaf malondialdehyde content than other treatments,but plant morphological indicators were inferior to T4.(3)Soil quality control:T2-T5 treatments significantly increased soil organic matter,ammonium nitrogen,available phosphorus,and available potassium contents;T2-T4 treatments significantly activated the activities of soil sucrase(+21%),urease(+111%),and acid phosphatase(+21%),promoting nutrient cycling.The comprehensive results showed that the comprehensive effect of replacing 80%compound fertilizer with humic acid from sugarcane leaves(T4 treatment)was the best.It provided technical support for resource utilization of sugarcane leaves and green cultivation of Siraitia grosvenorii by promoting plant growth,enhancing photosynthesis and stress resistance,and improving soil fertility.