Analysis On The Decomposition Characteristics Of Litter And Its Dynamic Interaction With Soil Nutrients In Jiuan Ecological Tea Garden In Central Guizho

Camellia sinensis is one of the characteristic tree species in Guizhou Province.The unique natural environmental conditions of Guizhou Province have given birth to rich resources of Guizhou characteristic tea.In the process of rapid development,with the production and utilization of people,the problems existing in the tea industry are also prominent.For example,the imbalance of nutrient elements,soil over-acidification,single planting of tea trees in a large area led to the singleness of tea garden ecological environment and the degradation of tea garden ecological environment.Therefore,selecting suitable tree species for ecological tea garden construction and using litter decomposition to improve soil nutrients is an effective way to solve the problem and realize the sustainable development of ecological tea garden.In this study,by using the method of in-situ decomposition,the leaf litter of four configure tree species in the ecological tea garden,Cinnamomum bodinieri、Betula luminifera、Cunninghamia lanceolata、Pinus massoniana and Camellia sinensis pruning were selected as the objects of study.The decomposition characteristics,nutrient release and soil nutrient dynamics of single decomposition and pairwise mixed decomposition at 1:1 were studied.The results are as follows:（1）The Betula luminifera litter showed unimodal type,the peak appeared in November,and showed seasonality.The litter of Camellia sinensis,Cinnamomum bodinieri,Pinus massoniana and Cunninghamia lanceolata showed bimodal type,and the peak time was different.The annual litterfall of the five kinds of litter is in the following order:Pinus massoniana(4361.86 kg·hm^-2·a),Betula luminifera(2169.69 kg·hm^-2·a),Cunninghamia lanceolata(2156.05 kg·hm^-2·a),Camellia sinensis(869.00 kg·hm^-2·a),Cinnamomum bodinieri(430.18 kg·hm^-2·a).The annual litterfall of Pinus massoniana is the largest and that of Cinnamomum bodinieri is the smallest.（2）For the single litters,the decomposition rate of Betula luminifera was the fastest and that of Cunninghamia lanceolata was the slowest in both two decomposition environments.Among the four kinds of mixed litter mixed with Camellia sinensis pruning,the decomposition rate of Camellia sinensis+Betula luminifera was the fastest in both two decomposition environments,and the decomposition in the tillage layer could shorten the half-life and turnover period of Camellia sinensis pruning decomposition to a greater extent.It accelerated the nutrient cycle in the ecological tea garden.Among the six kinds of mixed litter mixed by the pairwise configuration of tree species,the decomposition rate of Cinnamomum bodinieri+Betula luminifera was the fastest and that of Pinus massoniana+Cunninghamia lanceolata was the slowest in both two decomposition environments.From the perspective of the mixing effect,the tillage layer decomposition can make mixed decomposition produce a synergistic effect and promote litter decomposition.（3）The litter decomposes in different environments,and the change in nutrient content is greatly affected by the environment.Affected by the environment,the nutrient content showed an alternating change of increased-decreased（or decreased-increased）in the process of decomposition.And there was no significant species difference in the overall change trend of nutrient content.When litter decomposition in the tillage layer,the change of TK content showed some species difference.That is,TK content of coniferous tree litter showed an increasing trend as a whole,while that of broad-leaved tree litter and mixed litter showed a decreasing trend as a whole,and mixed decomposition could promote the release of TK content.During the decomposition on the soil surface layer,the TK content of litter showed a decreasing trend.The litter decomposed under two kinds of environments,and the lignin content showed an increasing trend as a whole.The content of cellulose content showed an increasing trend as a whole on the soil surface layer.（4）There are some differences in nutrient release patterns of litter decomposition in different environments.The TC,TN,TP and TK of litter were mainly released during the decomposition in both two decomposition environments.Lignin and cellulose are mainly enriched in both two decomposition environments.For the single litters,Betula luminifera had higher release rates of TC,TN,TP and TK in both two decomposition environments.From the point of view of the nutrient decomposition and release of the litter mixed with Camellia sinensis pruning,adding Cinnamomum bodinieri and Betula luminifera to Camellia sinensis pruning in the tillage layer for mixed decomposition can promote the decomposition and release of TC of Camellia sinensis pruning.Adding Betula luminifera and Pinus massoniana litter to Camellia sinensis pruning in both two decomposition environments for mixed decomposition can promote the decomposition and release of TN and TP of Camellia sinensis pruning.Adding Betula luminifera to Camellia sinensis pruning in both two decomposition environments for mixed decomposition can promote the decomposition and release of TK of Camellia sinensis pruning.From other mixed litter types,adding Betula luminifera to Cunninghamia lanceolata and Pinus massoniana in the tillage layer for mixed decomposition can promote the decomposition and release of TC,TN,TP,TK of Cunninghamia lanceolata and Pinus massoniana litter.Adding Cinnamomum bodinieri to Cunninghamia lanceolata and Pinus massoniana in the tillage layer for mixed decomposition can promote the decomposition and release of TK of Cunninghamia lanceolata and Pinus massoniana litter.Adding Betula luminifera to Cunninghamia lanceolata and Pinus massoniana on the soil surface layer for mixed decomposition can promote the decomposition and release of TC,TP of Cunninghamia lanceolata and Pinus massoniana litter.（5）Correlation decomposition shows that litter decomposition in both two environments can promote the release of TC and TN to a certain extent.The decomposition of Pinus massoniana,Cunninghamia lanceolata litter in both two decomposition environments is not conducive to the release of TP and TK,and adding broad-leaved tree litter to Pinus massoniana,Cunninghamia lanceolata litter for mixed decomposition can promote the release of TP and TK of Pinus massoniana and Cunninghamia lanceolata litter.During the decomposition in the tillage layer,Camellia sinensis,Cinnamomum bodinieri and Cunninghamia lanceolata were not conducive to the decomposition and release of lignin,and mixed litter had no significant effect.During the decomposition on the soil surface layer,Cinnamomum bodinieri,Cunninghamia lanceolata,Betula luminifera+Pinus massoniana were not conducive to the decomposition and release of lignin,while the mixed litter Camellia sinensis+Cinnamomum bodinieri,Camellia sinensis+Betula luminifera and Camellia sinensis+Cunninghamia lanceolata could promote the decomposition and release of lignin.The decomposition of Betula luminifera and Pinus massoniana in the tillage layer is not conducive to the release of cellulose,while the decomposition of Betula luminifera+Cunninghamia lanceolata and Pinus massoniana+Cunninghamia lanceolata can promote the release of cellulose.The decomposition of Camellia sinensis、Cinnamomum bodinieri、Cunninghamia lanceolata、Pinus massoniana、Camellia sinensis+Cinnamomum bodinieri、Camellia sinensis+Betula luminifera、Camellia sinensis+Pinus massoniana、Cinnamomum bodinieri+Betula luminifera、Cinnamomum bodinieri+Cunninghamia lanceolata on the soil surface layer can promote the release of cellulose,and show a certain degree of environmental difference,that is,the soil surface environment is more suitable for the decomposition and release of litter cellulose.（6）Litter decomposition can significantly increase soil nutrient content and soil p H value.The decomposition of single litter in the tillage layer had a better effect on the content of SOC,STN,SAN,STP,SAP,STK and SAK.Among them,the decomposition of Camellia sinensis、Cinnamomum bodinieri and Cunninghamia lanceolata can strongly promote the increase of SOC content.The decomposition of Cinnamomum bodinieri has a strong promoting effect on increasing the content of STN and SAN.The decomposition of Cinnamomum bodinieri and Pinus massoniana can strongly promote the content of STP and SAP.The decomposition of Camellia sinensis、Cinnamomum bodinieri and Pinus massoniana can strongly promote the content of STK and SAK.The decomposition of Pinus massoniana in the tillage layer can improve the soil p H value.The decomposition of Betula luminifera on the soil surface layer can improve the soil p H value.（7）The mixed litter had a better effect on the content of SOC,STN,SAN and SAP when it was decomposed on the soil surface layer.Among them,the decomposition of Camellia sinensis+Pinus massoniana,Betula luminifera+Cunninghamia lanceolata and Cinnamomum bodinieri+Pinus massoniana can strongly promote the content of SOC.The decomposition of Camellia sinensis+Cinnamomum bodinieri,Camellia sinensis+Pinus massoniana,Cinnamomum bodinieri+Pinus massoniana,Betula luminifera+Cunninghamia lanceolata has a strong promoting effect on soil N content.The decomposition of Camellia sinensis+Betula luminifera,Camellia sinensis+Cunninghamia lanceolata,Cinnamomum bodinieri+Pinus massoniana and Betula luminifera+Pinus massoniana can strongly promote the increase of SAP content.The contribution of mixed litter decomposition to the increase of STP content on the soil surface layer was lower than that in the tillage layer,and the decomposition of Camellia sinensis+Cinnamomum bodinieri,Camellia sinensis+Pinus massoniana and Betula luminifera+Pinus massoniana had a strong promoting effect on the increase of STP content.There was no environmental difference in the increase of soil K content by decomposition of the mixed litter.When the litter decomposes in the tillage layer,the decomposition of Betula luminifera+Pinus massoniana and Pinus massoniana+Cunninghamia lanceolata could increase STK content,the decomposition of Camellia sinensis+Cinnamomum bodinieri,Camellia sinensis+Betula luminifera and Betula luminifera+Pinus massoniana could increase SAK content.When the litter decomposes on the soil surface layer,the decomposition of Betula luminifera+Pinus massoniana can increase STK content,the decomposition of Camellia sinensis+Cunninghamia lanceolata and Betula luminifera+Pinus massoniana can strongly increase SAK content.The decomposition of Camellia sinensis+Pinus massoniana and Betula luminifera+Pinus massoniana in the tillage layer can improve the soil p H value.The decomposition of Camellia sinensis+Cinnamomum bodinieri,Camellia sinensis+Cunninghamia lanceolata,Cinnamomum bodinieri+Pinus massoniana and Betula luminifera+Pinus massoniana on the soil surface layer can improve the soil p H value.