生物炭介导下磷水平对连作苹果幼苗及土壤环境的影响

Effects of Phosphorus Level Mediated by Biochar on The Apple Seedlings and Soil Environment Under Continues Cropping

苹果连作障碍是制约苹果产业可持续发展的重要因素之一。研究生物炭介导下不同施磷水平对连作条件下平邑甜茶幼苗生物量、根系呼吸速率和土壤环境的影响,探讨生物炭配施磷肥这种措施对苹果连作障碍的防控效果,并筛选出合适磷肥用量,为生产中老果园改造提供理论依据。盆栽条件下,以苹果常用砧木-平邑甜茶为试材,设计了连作土壤(CK)、连作土用溴甲烷熏蒸处理(F)、连作土+2%生物炭(B)、连作土+2%生物炭+0.5‰磷肥(BP0.5)、连作土+2%生物炭+1‰磷肥(BP1)和连作土+2%生物炭+2‰磷肥(BP2)6个处理。采用常规方法测定了不同处理对平邑甜茶幼苗生物量、根系呼吸速率、土壤养分和土壤酶活性的影响。结果表明:溴甲烷灭菌后,幼苗的株高、地径、鲜重和干重均远远高于连作土,分别是连作土中幼苗的1.6,1.5,2.9,2.5倍,幼苗的根系呼吸速率及保护酶也远远高于对照和其他处理。生物炭、或者生物炭配施磷肥,均可提高平邑甜茶幼苗的生物量,幼苗的株高、地径、鲜重和干重分别是连作土中幼苗的1.2,1.1,1.6,1.4倍和1.4,1.2,2.2,1.9倍,2种处理的根系呼吸速率也有大幅度提高;生物炭配施0.5‰磷肥可明显提高幼苗根系SOD、POD和CAT酶活性,同时降低MDA含量;与对照相比,生物炭配施0.5‰磷肥能明显提高土壤中有机质含量,增加硝态氮和速效磷的含量,促进土壤中脲酶、蔗糖酶和磷酸酶的活性。综合分析比较,生物炭配施0.5‰磷肥相比于单施生物炭,能更好的提高连作条件下平邑甜茶幼苗的生长发育,增加土壤有机质含量,增强土壤酶活性。因此,生物炭配施磷肥这一综合措施能更好的防控苹果连作障碍。

Apple replant disease（ARD）is a major factor that restricted the sustainable development of apple industry.In this study,the apple plant seedling biomass,root repiration rates,soil enzyme activities and soil environments under different phosphorus levels in continues cropping soil were determined to reveal the effect of biochar combined with phosphorus fertilizer on the control of ARD and select suitable amount of phosphate fertilizer,so as to provide theoretical basis for the renewal of old orchard and the prevention and control of ARD.Pot experiments including six treatments,which were the control（CK）,methyl bromide sterilization（F）,2% biochar（B）,2% biochar ＋ 0.5‰ phosphate fertilizer（BP0.5）,2% biochar ＋ 1‰ phosphate fertilizer（BP1）and 2% biochar＋ 2‰ phosphate fertilizer（BP2）,were carried out.The biomass and root respiration rate of Malus hupehensis Rehd.seedlings,soil nutrient and soil enzyme activity were measured byconventional methods.The results showed that methyl bromide sterilization treatment increased heights,ground diameters as well as fresh and dry weights of seedlings,which were 1.6,1.5,2.9 and 2.5 times of the seedlings in the control,respectively.The root respiratory rates and activities of protective enzymes in the F treatment were all higher than those in the control or other treatments.The treatments of B and BP0.5 both significantly enhanced heights,ground diameters,fresh and dry weights of seedlings,which were 1.2,1.1,1.6,1.4 and 1.4,1.2,2.2 and 1.9 times of the seedlings in the control,respectively.The root respiration rates increased significantly in the treatments of B and BP 0.5.Biochar combined with 0.5‰ phosphate fertilizer improved the activities of SOD,POD and CAT,and decreased the content of MDA in the seedling roots.Compared with the control,biochar combined with 0.5‰ phosphate fertilizer significantly improved the content of organic matter in soil,increased the contents of nitrate nitrogen and available phosphorus,and promoted the activities of urease,sucrase and phosphatase in soil.In conclusion,compared to the single application of biochar,application biochar combined with phosphate fertilizer could improve the development of M.hupehensis seedlings under continues cropping,increase soil organic matter content,enhance soil enzyme activity.Therefore,the integrated measures of biochar and phosphate fertilizer can better prevent and control ARD.