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【Objective】 The present paper aimed to explore the changes of physicochemical properties and soil enzyme activities that are closely related to the occurrence of continuous cropping obstacles after the application of exogenous Methyl jasmonate（MeJA）.【Method】The three-year continuous cropping soil and red cheek strawberry were used in this paper to study the changes of physicochemical properties and soil enzyme activities of strawberry rhizosphere soil after applying different concentrations（0, 10, 50, 100, 200, 500 μmol/L） of exogenous MeJA. Indicators such as soil nutrient content, soil pH, soil enzyme activity, fruit number per plant, and single fruit weight were investigated.【Result】 Compared with CK treatment without MeJA, the contents of organic matter, alkali hydrolyzable nitrogen, available phosphorus and potassium of strawberry rhizosphere soil treated with MeJA decreased in general, which mostly significant, whether in the seedling stage or the flowering and fruiting stage; The pH of MeJA treatment was higher than that of the control treatment, and reached a significant level at the seedling stage, with an increase range of 3.90%-5.58%; The activities of peroxidase, polyphenol oxidase, protease and urease of MeJA treatment were generally improved compared with the control treatment, and most of them reached a significant degree; Compared with CK, MeJA treatment significantly reduced the plant height of strawberry by 22.33%-27.19%, and increased the number of strawberries per plant, of which treatment with 100 μmol/L MeJA increased by 26.25%. The effects of different concentrations of MeJA on the single fruit weight of strawberry showed a trend of increasing first and then decreasing, and the specific order was 100>50>10>0>200>500 μmol/L. Compared with CK, treatments with 50 μmol/L and 100 μmol/L significantly increased by 4.02%-31.60%. After the application of exogenous methyl jasmonate, the changes of soil nutrients, pH and soil enzyme activities in strawberry rhizosphere showed a transition rule at 100 μmol/L or its adjacent concentration with the increase of MeJA concentration. 【Conclusion】 After the application of an appropriate amount of exogenous methyl jasmonate, the continuous cropping strawberry showed that the rhizosphere soil nutrients were more absorbed, the soil acidification degree was alleviated, and the soil enzyme activity increased, which increased the number of fruits per plant and the single fruit weight of strawberries. However, the above trend was reversed with increasing MeJA concentrations. The above findings were beneficial to guide the production practice to apply exogenous methyl jasmonate to improve the physicochemical properties and soil enzyme activities of continuous cropping strawberry rhizosphere soil, so as to promote plant growth and alleviate continuous cropping obstacles. [ABSTRACT FROM AUTHOR]

【Objective】Through the comparison of models, the present paper aimed to explore the influence of ’chninese milk vent Returning to the Field coupled with rice and fish symbiosis’ on the soil nutrients and yield of rice, and provided a scientific basis for efficient and high-quality rice production and sustainable development.【Method】In this experiment, four treatments including conventional rice planting as a control(CK), chninese milk vent Returning to the Field(ZD), rice and fish symbiosis(YD),chninese milk vent Returning to the Field coupled with rice and fish symbiosis(ZY), measuring, analysis and comparison of the contents of soil nutrients(organic matter,total nitrogen, total phosphorus,total potassium and their effective state), rice yield and yield component index of each treatment were performed.【Result】Compared with CK, YD, ZD and ZY can effectively improve the soil fertility of rice in the current season, and ZY has the best effect. Compared with CK, soil organic matter, total nitrogen, total phosphorus, total potassium and their effective state content of ZY mature period were increased by 16.40 %, 18.18 %, 20.63 %, 3.42 %, 7.71 %, 15.96 % and 1.85 %(P<0.05); ZD can effectively alleviate soil acidification, and the soil pH at maturity was 6.06,which compared with CK, YD and ZY, it increased by 0.04, 0.12 and 0.08 units, and the difference was significant(P <0.05);Compared with CK,ZY, ZD, and YD can increase the yield of rice in the season effectively, and ZY has the highest yield of rice, reaching 6.29 t/hm~2. Compared with CK, ZD and YD, the actual yield of ZY increased by 4.83 %-11.33 %,and the difference was significant(P <0.05).【Conclusion】In summary, chinese milk vent returning to the field coupled with rice and fish symbiosis can effectively improve soil fertility and significantly increase rice production in the current season, which was an greenand efficient way of fertilizing. [ABSTRACT FROM AUTHOR]

This paper studies and discusses the changes of soil chemical indexes in different recovery years of XingJ an larch forest in Daxinganling, Inner Mongolia, in order to evaluate the self recovery of natural forest and provide basis for the management of Daxin- ganling forest in Inner Mongolia. The pH, C content, whole nitrogen, whole phosphorus and whole potassium content of the soil used in the experiment were calculated according to the Forest Soil Experiment Tutorial and the Soil Agroization Analysis. The effects of logging interference on the chemical properties of soil were studied using a single - factor variance ( ANOVA) analysis ( SPPS 13. 0 software). Results showed that ： ® comparing the differences in soil pH, soil C and other nutrients in Xing * an larch natural forest and two differ¬ent interference plots of clear cut and gradual cut, it is found that clear cut and gradual cut have significant differences in soil chemical properties (P<0.05). Clear cut has an extreme significant positive correlation with soil total nitrogen (P<0.01) , and a significant positive correlation with soil carbon content and pH ( P < 0. 05 ). (2) Comparing the significance of different cutting methods on soil physical and chemical properties in different years, there is a certain gap between the logging sites in 1987 and 2014, while the differ¬ences between the logging sites in 2009, 1987 and 2014 are not significant. Conclusion ： deforestation interference can reduce the pH of soil, objectively increase soil nutrients, and may be conducive to the natural renewal of forests. Logging interference significantly af¬fects the balance of soil carbon and other nutrients [ABSTRACT FROM AUTHOR]