苹果园间种紫花苜蓿和香薄荷的根系分泌物对土壤肥力的影响

Effects of root exudates of alfalfa and mint intercropped in apple orchards on soil fertility

【目的】为确立果园间种植物对果园土壤的反馈效应。【方法】将富士苹果幼苗(Malus domestica)盆栽在间作过一年植物的果园土壤中,在盆栽中间种紫花苜蓿(Lablab purpureus)、香薄荷(Saturela hortensis),模拟果园间种模式,测定土壤理化指标、酶活性及根系分泌物。【结果】间作过薄荷植物的土壤中种植苜蓿提高了速效磷15.95%、速效钾125.44%,而连作香薄荷对土壤肥力无明显影响,连作紫花苜蓿会使土壤全磷、全钾分别下降23.30%,33.63%。间作过薄荷植物的土壤间种苜蓿相较于种植薄荷,在8月份可以提高土壤中44.50%铁和31.56%锰。对间作过一年紫花苜蓿和香薄荷的土壤根系分泌物分析表明,差异物质主要由糖类、醇类、醛类以及酸类组成,其中酚酸类物质阿魏酸和苯甲酸会对苜蓿产生自毒作用。【结论】果园轮作植物能够使果园土壤肥力上升,加速土壤有效态营养元素转化,提高土壤酶活性。

【objective】To establish the feedback effect of inter-orchard plants on orchard soil.【Methods】Apple(Malus domestica‘Red Fuji’)seedlings were potted in the soil of the orchard with intercropping plants for one year,alfalfa(Lablab purpureus)and mint(Saturela hortensis L.)were planted in the soil,and the intercropping model was simulated.The soil physical and chemical indexes,enzyme activities and root exudates were evaluated.【Results】Alfalfa intercropped with menthol plants increased available P at 15.95%and K at 125.44%,while continuous cropping of menthol had no significant effect on soil fertility.Continuous cropping of alfalfa reduced total P and K at 23.30%and 33.63%,respectively.Compared with mint planting,alfalfa intercropped with mint plants could increase 44.50%iron and 31.56%manganese in soil in August.The analysis of root exudates of alfalfa and mint intercropped for one year showed that the different substances were mainly composed of carbohydrates,alcohols,aldehydes and acids.Among them,phenolic acids ferric acid and benzoic acid had cytotoxic effects on alfalfa.【Conclusion】In the orchard,rotation plants can increase soil fertility,accelerate the transformation of available nutrient elements and increase soil enzyme activity.