| Compared with the governance of the black soil land,the research of"bare land of mountain"governance is still in the early stage.In order to study the rapid vegetation-soil treatment technology of"bare land of mountain",this study uses the six measures in the pilot project of"bare land of mountain"treatment in Dari County,Guoluo Prefecture,namely:“micro tiller plowing+manual sowing（MT1+MS）,micro-tiller plowing twice+manual sowing（MT2+MS）,rotary tiller ploughing+seeder sowing（RT+SS）,excavator ditching+manual sowing（ED+MS）,no-till sowing（NT+S）,manual rake+manual sowing（MR+MS）”treated grassland is the research object.By studying the characteristics of grassland vegetation and community,as well as the physical and chemical characteristics of soil and changes in microbial biomass,from the input-output ratio and governance effect comprehensive analysis of different governance measures.The main research conclusions are as follows:1.Under the measures MT1+MS,MT2+MS,RT+SS,the coverage,height,aboveground biomass and important values of Elymus sibiricus cv.Tongde were higher,and the cover and aboveground biomass of Poa pratensis cv.Qinghai were significantly highest in measure RT+SS（P<0.05）;the cover and aboveground biomass of other species in the community were significantly highest in measure NT+S（P<0.05）;There was a very significant positive correlation between the total cover and the total aboveground biomass（P<0.01）.The differences in total coverage among measures MT1+MS,MT2+MS,and RT+SS ranged from 4.33%to 17.00%,and the differences in total aboveground biomass ranged from 39.94 to 82.83 g·m-2;Belowground biomass was mainly in the surface layer,and there was no significant difference among the six measures,but it was significantly positively correlated with soil organic carbon（P<0.05）;Margalef index and Shannon-Wiener index were highest in measure NT+S,pielou index was highest in measure MT1+MS,but only margalef index was significantly different between measures（P<0.05）.Margalef index was significantly positively correlated with total cover and total aboveground biomass（P<0.05）.And the pielou index was significantly positively correlated with the total coverage（P<0.05）.2.Under different treatment measures,the soil water content decreased continuously with the deepening of the soil layer depth;the soil water content was the highest under the measure NT+S when the soil water content was 0-10 cm and 10-20cm,and the soil water content of the measure ED+MS was the highest in each soil layer.The change of bulk density is opposite to water content,the bulk density of measure ED+MS is significantly highest in each soil layer（P<0.05）;The mass percentage of soil water-stable aggregates in the 0-10 cm soil layer was significantly highest in the measure NT+S（P<0.05）,and there was no significant difference between the measures in the 10-20 cm and 20-30 cm soil layers;The distribution of aggregates in each layer of soil with different treatment measures is dominated by aggregates with particle sizes of 0.05-0.25 mm and 0.25-1 mm.The mass of aggregates>1 mm was significantly highest in the 0-10 cm and 20-30 cm soil layers under the measure NT+S（P<0.05）,and the 10-20 cm soil layer was significantly the highest under the measure MT1+MS（P<0.05）.The aggregate quality of 0.25-1 mm has no significant difference in each soil layer and each measure;The aggregate quality of 0.05-0.25 mm is the lowest in the 0-10 cm and 10-20 cm soil layers in the measure NT+S,and in the measure ED+MS was the highest（P<0.05）;there was no significant difference among the measures in the 20-30 cm soil layer,and the aggregate quality of<0.05 mm was not significantly different among the six measures in each soil layer.3.The soil p H value under different treatment measures was between 6.75 and7.84,and the p H value was significantly highest in each soil layer of the measure MT1+MS（P<0.05）;The contents of soil nitrate nitrogen,ammonium nitrogen,organic carbon,total nitrogen and total phosphorus decreased continuously with the deepening of the soil layer,and except for nitrate nitrogen,the other nutrients in each soil layer were the highest in the measure NT+S,and total phosphorus content was significantly highest in each soil layer（P<0.05）;Soil total phosphorus and total nitrogen had a very significant positive correlation（P<0.01）,and the soil bulk density was significantly negatively correlated（P<0.05）;soil total nitrogen was significantly positively correlated with water content（P<0.05）,and extremely significantly negatively correlated with bulk density（P<0.01）.4.The content of carbon,nitrogen and phosphorus in microbial biomass decreased continuously with the deepening of soil layer.The microbial biomass carbon content was significantly highest in each soil layer of the measure NT+S（P<0.05）,and was significantly positively correlated with the microbial biomass nitrogen and phosphorus content（P<0.01）,and was significantly positively correlated with the water-stable aggregate content.The microbial biomass nitrogen content was significantly the highest in each soil layer of the measure NT+S（P<0.05）,and was significantly positively correlated with the microbial biomass phosphorus content（P<0.01）;The microbial biomass phosphorus content in the 0-10 cm and 10-20 cm soil layers was significantly highest in the measure NT+S（P<0.05）,and the difference between the measures in the 20-30 cm soil layer was not significant.5.From the input-output ratio,the six control measures are ranked as MT2+MS>MT1+MS>RT+SS>ED+MS>NT+S>MR+MS;From the vegetation-soil governance effect,the six measures were ranked as follows:MT1+MS>NT+S>RT+SS>MT2+MS>ED+MS>MR+MS.Therefore,it is recommended to adopt the control measures of micro tiller plowing+manual sowing in the degraded grasslands of"bare land of mountain"in the source region of the Three Rivers... |
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