Research And Application Of Preventing And Controlling Obstacles Of Strawberry Continuous Planting In Greenhouse

In view of the increasingly prominent situation of strawberry continuous cropping obstacles in greenhouse cultivation,the main factors causing strawberry continuous cropping obstacles in suburban greenhouse of Nantong City,Jiangsu Province were investigated and analyzed.With the increase of continuous cropping years,soil acidification,secondary salinization,nutrient enrichment,decrease of enzyme activity and destruction of microbial ecological balance were the main causes of Strawberry continuous cropping obstacles in greenhouse for three years.PH value was 0.44 lower than CK at 5.79,EC value was 0.09 mS/cm higher than CK at 0.52 mS/cm,total nitrogen content was 4.05 g/kge,67.4%higher than CK at 3 years,total phosphorus,available phosphorus,total potassium and available potassium increased with continuous cropping,catalase decreased to 0.54 ml/g,sucrase decreased to 79.88 mg/g,urease and phosphatase decreased to 7.30 mg/g and 22.89 mg/g respectively at 3 years.Bacteria decreased by 16.1 9%,actinomycetes decreased by 11.4%,fungi increased by 49.8%and bacteria/fungi decreased by 123.4%from 2202.The analysis of the relationship between soil fertility and microbial quantity and enzyme ctivity in strawberry continuous cropping showed that salts and available phosphorus were positively correlated with the number of fungi,negatively correlated with the number of other microorganisms and enzyme activity.The direct effects of available phosphorus and salinity on the number of bacteria were-8.719 and-6.217,respectively.The indirect effects of salinity on the number of bacteria through available phosphorus were-8.597 and that of available phosphorus was-8.597.The indirect influence of excess salt on the number of bacteria was-6.130;The direct influence of salt on the number of fungi was up to 15.713;The direct influence of available phosphorus and salt on the number of actinomycetes was-2.693 and-2.515,respectively.The indirect influence of available phosphorus on the number of actinomycetes was-2.479 through salt and-2.656 through available phosphorus.The direct influence of available phosphorus on the activity of catalase was-14.642,the direct influence of available phosphorus on the activity of catalase was-14.436,the direct influence on the activity of invertase was-13.480,the indirect influence of pH on the activity of invertase was as high as 12.926,the direct influence on the activity of urease was-7.757,and the direct effect of available potassium on the activity of urease was as high as-13.480.The indirect influence was-7.612.The direct influence of total nitrogen on phosphatase activity was-14.818,but the indirect influence of total nitrogen on phosphatase activity was-14.781 through salinity.Salt accumulation and available phosphorus accumulation are two important factors affecting soil microbial biomass and enzyme activity of strawberry continuous cropping in greenhouse.The water(limited)dry rotation method effectively solved the problems of soil acidification,secondary salinization,nutrient enrichment and microbial ecological balance destruction.The single fruit weight and soluble solids content of "Red Cheek" strawberry increased by 17.7%and 4.3%respectively after treatment,and the strawberry yield reached 33101.9 kg/hm2,which was 12.9%higher than before treatment.The application of 900 kg/hm2 of lime nitrogen and 45 000 kg/hm2 of green straw(comminution)improved soil health,prevented root-knot nematode and inhibited weed growth;significantly improved fruit quality and yield,with a single fruit weight of 20.8 g,soluble solids content of 12.3%;and the yield of 33 214.3 kg/hm2,20.1%higher than CK.