Study On The Effect Of Residue Treatment Methods On Eucalyptus Soil Aggregates And Nutrients

Burning is a common land preparation method used in the management of eucalyptus plantations.Although it can reduce weeds and facilitate afforestation,it is likely to cause soil erosion and fire hazards in the woodland,and cause problems such as lower growth of eucalyptus forests.However,how does the soil aggregates of the eucalyptus plantation respond to the site preparation method of mountain-free mountain preparation?What is the impact on soil nutrients?There is still a lack of research on these issues.This paper focuses on the effects of eucalyptus cutting residue treatment methods on soil aggregates and soil aggregates related nutrient content,and intends to provide a theoretical basis for eucalyptus plantation free-slashing afforestation.In this paper,the fourth-generation Eucalyptus urophylla plantation soil of the Guangxi State-owned Daguishan Forest Farm in the main eucalyptus producing area is used as the research object.A randomized block experiment design is used to compare the treatment of eucalyptus with two different residue treatment methods.Forest soil aggregate composition,soil aggregate stability and soil aggregate related nutrients;each treatment was repeated 3 times,collecting soil profiles of 0-20 cm,20-40 cm,40-60 cm,and 60-80 cm Samples were measured for soil aggregate composition,soil aggregate-related C,N,and P content,and soil aggregate-related urease,invertase,acid phosphatase and catalase content.The main research conclusions are as follows:(1)Analysis of variance,correlation analysis,etc.show that the soil aggregates under the mountain-free treatment are more stable than the soil aggregates treated by the mountain-smelting treatment.When the thickness of the soil layer is 0-20 cm,20-40 cm,40-60 cm and 60-80 cm,the composition ratio of water stability and mechanical stability of>0.25 mm soil aggregates is in the order of:mountain.(2)In the same soil layer,the MWD and GMD soil aggregates of the two residue treatment methods,namely,no smelting and smelting,show the same trend,that is,no smelting>smelting.With the deepening of the soil layer,the MWD and GMD of the soil aggregates of the two different residue treatment methods showed a trend of first increasing and then decreasing.The method of residue treatment has a certain influence on the stability indexes of soil aggregates,MWD and GMD.In general,the degree of aggregation of the soil aggregates of the two different residue treatment methods is better and the soil structure is better.stable.(3)Studying the influence of residue treatment methods on the distribution of soil aggregate-related nutrient indicators found that the soil aggregate-related organic carbon,total nitrogen and total phosphorus under the smelting-free treatment are higher than those of the smelting treatment.Under different soil layers,the content of organic carbon,total nitrogen,and total phosphorus in soil aggregates of the two residue treatment methods of mountain-free smelting and mountain smelting changed consistent with the depth of the soil layer,and showed a trend of gradual decrease with the increase of soil layer thickness.(4)Studying the influence of residue treatment methods on the distribution of relevant nutrient indicators of soil aggregates and found that the activities of catalase,acid phosphatase,urease and invertase associated with soil aggregates under the mountain-free treatment are higher than those of the mountain-refining treatment,Under different soil layers,the catalase,acid phosphatase,urease and invertase activities of soil aggregates of the two residue treatment methods of mountain-free and mountain-refining change consistent with the depth of the soil layer,and the performance increases with the depth of the soil layer.Out of a gradual decrease.(5)There is a significant positive correlation between the stability of soil aggregates and the content of organic carbon and total phosphorus in the aggregates,and there is a positive correlation between the stability of soil aggregates and the content of total nitrogen.Among them,GMD and WMD are negatively correlated with total phosphorus in soil aggregates<0.25 mm,and there is a significant positive correlation between organic carbon related to each particle size of soil aggregates and total phosphorus in soil aggregates<0.25 mm,and soil aggregates>2mm are related to total phosphorus.Related total nitrogen has a significant positive correlation with WMD.Stability of soil aggregates Aggregate-related urease and acid phosphatase activities have a significant negative correlation with the stability of soil aggregates.Among them,0.25-0.053 mm catalase activity has a significant positive correlation with>0.25 mm sucrase activity,and a negative correlation with acid phosphatase.<0.25 mm acid phosphatase has a negative correlation with sucrase.To sum up,we believe that the non-smelting soil will decompose a large amount of organic matter such as humus after the cutting residues are spread on the surface,which increases the surface organic matter content,accelerates the plant-soil cycle,and eliminates the surface of the soil after the smelting treatment.Good soil aeration is conducive to microbial metabolic activities,as well as the accumulation of nutrients,and accelerate the circulation of soil nutrients,thereby promoting the increase in soil fertility.