万寿菊秸秆用于苹果连作土壤生物修复材料的潜力

Potential of marigold straws used for biological disinfestation to continuous cropped apple orchard

[目的]万寿菊秸秆具有抑制有害微生物的作用,而苹果产业的可持续发展受到连作障碍的严重制约。本文研究了利用万寿菊进行连作土壤生物消毒的效果,为万寿菊秸秆的有效利用和苹果连作障碍的生物防控寻找可行的方案。[方法]2017年以平邑甜茶幼苗为试材,以26年苹果树下棕壤为供试土壤进行了盆栽试验。设4个万寿菊秸秆粉加入量0、12、30、60 g/kg,与土壤混合,浇水,幼苗移栽之前用薄膜覆盖15天,揭开晾7天。同时,设置一组不添加万寿菊粉也不用薄膜覆盖的处理作为对照(CK)。在幼苗生长3个月后开始取植株样,每隔一个月取一次,共采集三次,同时采集土壤样品。测定了平邑甜茶幼苗生长指标、光合参数、根系呼吸速率、保护性酶活性及土壤微生物等相关指标。[结果]与不添加万寿菊粉处理(0 g/kg)相比,万寿菊粉不同添加量处理均能显著增加根系呼吸速率,提高根系保护性酶活性;提高了平邑甜茶幼苗叶片的光合参数,促进连作平邑甜茶幼苗生长;优化土壤微生物环境。综合各指标,以30 g/kg处理的效果最好,与不添加万寿菊粉处理相比,平邑甜茶幼苗的根系呼吸速率增加56.6%,根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性分别增加48.7%、113.5%、115.2%。株高、地径、地上部鲜重、叶片叶绿素含量分别增加183.3%、55.5%、221.5%和17.3%。净光合速率(Pn)提高了83.6%,水分利用效率(WUE)提高了57.1%。上述各指标均与0、12、60 g/kg处理差异显著。添加万寿菊秸秆粉处理土壤后,土壤细菌增加,真菌减少,12、30、60 g/kg添加量的土壤细菌/真菌比值分别为99.3、265.7、197.3,分别是不添加处理的1.4倍、3.7倍、2.7倍,处理间差异显著。土壤中的尖孢镰孢菌基因拷贝数均降低,分别比不添加万寿菊粉处理下降18.6%、57.1%、40.4%,处理间差异显著。T-RFLP结果表明,不添加万寿菊粉处理(0 g/kg)与添加12 g/kg处理的真菌群落结构相似,30 g/kg与60 g/kg添加量的真菌群落结构较为相似,均与CK有明显差异。万寿菊添加量60g/kg处理的各指标虽然优于对照,但不如添加量30 g/kg处理的。试验中发现连作土只覆膜处理虽然对各指标的改善有一定的作用,但效果不明显。[结论]在连作土壤上施用适宜量的万寿菊秸秆粉,能降低土壤尖孢镰孢菌的基因拷贝数,明显改变连作土壤的真菌群落结构,提高平邑甜茶幼苗根系的呼吸速率和保护性酶活性,促进幼苗的生长,提高幼苗的光合效率,有效缓解苹果连作障碍。因此,万寿菊秸秆粉是一种有效的连作土壤修复材料,其在生产实践中的适宜添加量需要进一步研究。

【Objectives】Marigold straws have been proved possessing inhibition effect on some harmful microorganisms.At the same time,apple industry is suffering from seriously continuous cropping obstacle restricts.The effect of biological disinfestations of marigold straws was studied,to study the recycle of organic wastes and the reform of aged apple orchards.【Methods】A pot experiment was carried out in 2017,the seedlings of Malus hupehensis Rehd.were used as test materials and a continuous cropped soil(26 years'apple orchard)as tested soil.Marigold(Tagetes erecta)straw powder of 0,12,30 and 60 g/kg were mixed with soil,watered and mulched with plastic film for 15 days before planting the seedlings.After three months'growth,the seedling samples were collected,and total of three samplings were made every one month interval.Soil samples were collected at the same time.The growth indices,photosynthetic parameters,root respiration rate and protective enzyme activity of Malus hupehensis Rehd.seedlings,and soil microorganisms were measured.【Results】Compared with 0 g/kg treatment,the biological disinfestation to soil mixed with marigold powder could significantly increase root respiration rate significantly,raise protective enzyme activity;and then improve the leaf photosynthetic parameters,promote the seedling growth indices;optimize the soil microbial environment.Comprehensively evaluated,the 30 g/kg treatment was the best.Compared with 0 g/kg treatment,the root respiration rate was increased by 56.6%,the activities of SOD,POD and CAT were increased by 48.7%,113.5%and 115.2%respectively and the plant heights,ground trunk diameters,the fresh weights of plant above ground and leaf chlorophyll contents were increased by 183.3%,55.5%,221.5%and 17.3%,respectively.The net photosynthesis rate(Pn)and the water use efficiency(WUE)of leaves increased by 83.6%and 57.1%,respectively.And all the above indices were significantly different from those of 0 g/kg,12 g/kg and 60 g/kg treatments.The soil bacteria population was increased and the fungi population was decreased after biological disinfestation.The ratio of bacteria to fungi in soil treated with 12,30 and 60 g/kg were 99.3,265.7 and 197.3,respectively,which were 1.4,3.7 and 2.7 times of the 0 g/kg treatment,with significant differences among the treatments.The number of gene copies of Fusarium oxysporum in soil decreased by 18.6%,57.1%and 40.4%compared with the 0 g/kg treatment,respectively,which were significant differences among treatments.terminal restrietion fragment length polymorphism(T-RFLP)results showed that the soil fungal community structure of 0 g/kg was similar with that of 12 g/kg,and the fungal community structure of 30 g/kg was relatively similar with that of 60 g/kg,both of them were completely separated from that of CK.The powder dosage was not the more the better,60 g/kg treatment was better than 0 g/kg,but not as good as the 30 g/kg treatment.The merely film mulching treatment(0 g/kg)improved various indices a little bit,but the effect was not significant.【Conclusions】Biological disinfestation to soil with marigold powder in a proper rate could reduce the number of gene copies of Fusarium oxysporum in soil,change the fungal community structure within continous cropped soils significantly;enhance root respiration rate and protective enzyme activity of apple seedlings;significantly promote the growth of Malus hupehensis Rehd.seedlings,improve the photosynthetic parameters,and effectively alleviate apple continous cropping barrier.Therefore,marigold straw powder is an effective soil remediation material for continuous cropping,and its suitable addition amount in production needs further study.