| Guided by the idea of near-natural forest management,using the method of forest gap interference,based on the control of forest gap area,explore the influence of age and area of Masson pine forest gap on soil microbial and enzyme activity characteristics over time.In this study,seven types of forest gaps of 39 years old masson pine plantation(G1:100m~2,G2:225 m~2,G3:400 m~2,G4:625 m~2,G5:900 m~2,G6:1225 m~2,G7:1600 m~2)and pure forest undergrowth are the research objects.Seven years after the formation of the forest gap,based on the research data of the forest gap formation for one year,the analysis and comparison of different forest gap ages,The effect of area on soil microbial biomass carbon(MBC),microbial biomass nitrogen(MBN),microbial biomass phosphorus(MBP),soil protease,hydroxylamine reductase,urease,nitrite reductase activity characteristics.The main findings are as follows:(1)Compared with the forest gaps of 1 year old,the soil microbial biomass C,N,P and soil enzyme activities of the forest area of 7 years old with the same area have increased value,which indicates that the forest gap interference has a negative impact on soil microbial biomass and soil enzymes The increase in activity has a positive effect,showing that the longer the gap between the forest gaps,the greater the soil microbial biomass and the stronger the soil enzyme activity.(2)Compared with the 1-year-old forest gap,the peak age of soil protease activity in the 7-year forest gap appears in summer and spring(of which G6 forest gap has the greatest impact),and the trough period occurs in autumn and winter,and the nitrite reductase activity season The dynamic changes are consistent,which is contrary to the seasonal dynamic changes of urease enzyme activity;the peak of hydroxylamine reductase activity occurs in spring and summer(of which G5 forest gap has the greatest impact),and the trough period occurs in autumn and winter,indicating soil enzyme activity The peak is mainly in the season with higher temperature,relatively speaking,the medium and large(G5,G6)forest gap reconstruction effect is best.(3)Compared with 1 year old forest gaps,7 age G3,G4,and G5 forest gaps have the greatest impact on soil microbial biomass,so medium area(G3～G5)forest gaps are more suitable as forest gap intervention standards over time.(4)Changes in age and area of the forest gap have extremely significant effects on soil microbial biomass and soil enzyme activity(P<0.001);the interaction between the two has an extremely significant level of effect on soil enzyme activity(P<0.001),This indicates that the gap age and gap area reflect the period and intensity of disturbance,and are the key factors that determine the success of plant regeneration in the gap period;the interaction between gap age and gap area has no effect on MBC,MBN,MBP Reaching a significant level is probably due to insufficient time for forest gap interference,and the specific mechanism needs further study.In summary,with the passage of the age ofthe forest gap,the G3～G5(400～900㎡)forest gap reconstruction effect is the best,and the important role of the time effect on the interference of the forest gap is deeply understood.The conclusions of the study provide relevant technical parameter selections for the continuous development of window-type near-natural transformation of Pinus massoniana plantation pure forest,and also provide a reference for the transformation of large-scale artificial forest and sustainable management of near-natural forest. |
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