| Tea pruned litter decomposition is an important source of organic carbon in tea plantation soil,and carbon release from pruned litter is an important factor affecting the change in organic carbon in tea plantation soil.Previous study have found that there are differences in soil carbon pools after planting different varieties of tea,and how they are affected by the return of pruned litter is not clear.A decomposition experiment of pruned litters with different tea varieties（C.sinensis‘Fuding Dabaicha’（FD）,Chuancha No.3（CC3）,Chuanmu No.217（CM217）and Chuannong Huangyazao（CN））was conducted to clarify the dynamics of decomposition and organic carbon release of pruned litter,change in soil organic carbon of different tea varieties.The main research results are as follows:（1）The mass loss rate of pruned litter of different tea varieties increased in the decomposition time.The quality loss in the early stage（0-120 days）of decomposition is 2.42～2.84 times than that the later stage（120-360 days）,which has the characteristics of fast decomposition in the early stage and slow decomposition in the later stage.After 360 days of decomposition,the trimmed litter in the in-situ decomposition test showed a higher quality loss rate（53.49%～62.19%）,which was 1.53～1.59times higher than that in the indoor decomposition test.There were differences in the decomposition ability of pruned litter among different varieties of tea trees,with decomposition coefficients ranging from large to small:CM217（1.111）,FD（1.087）,CC3（0.964）,and CN（0.973）,indicating that the pruned litter of FD and CM217 decomposed faster.The difference in the decomposition rate of pruned tea litter among different varieties is influenced by the initial chemical composition of the pruned litter,among which the C content,lignin content,cellulose content,and lignin/N are significantly correlated with the decomposition rate（P<0.05）.The decomposition process of pruned litter released a large amount of C（55.09%～61.65%）,and the C release rate of pruned litter of different tea varieties was significantly correlated with the quality loss rate（P<0.05）.FD and CM217 tea trees decomposed faster and had stronger C release ability.（2）The variation rates of different carbon components in tea tree pruned litter were in descending order:water-soluble components（79.58%～82.23%）,organic soluble components（75.28%～78.34%）,acid soluble components（58.96%～66.20%）,and acid insoluble components（37.28%～38.96%）.There are differences in the decomposition dynamics of carbon components in pruned tea litter of different varieties.In the early stage of CM217 pruned litter decomposition,water-soluble components decomposed faster,while in the later stage of FD pruned litter decomposition,acid insoluble components decomposed faster.The path analysis results showed that the decomposition of water-soluble and acid-insoluble components had a significant impact on the release rate of pruned leaf C（P<0.05）,while the pruned leaf C release rate had a significant impact on the LOCI content in the 0-5 cm soil layer（P<0.05）.During the decomposition process of tea tree pruned litter,the soil LOCI content showed a trend of first decreasing and then increasing.The soil planted with CM217 had a smaller rate of change in LOCI due to the higher carbon release from the pruned litter in the early stage,and the decomposition of CN pruned litter was slower.The soil organic carbon LOCI content increased significantly in the later stage of decomposition,from 6.32 g kg-1 to 7.35 g kg-1.（3）During the decomposition process of tea tree pruned leaves,a large amount of DOC was released(9.31 g kg-1～32.20 g kg-1).CM217 and CC3 decomposed faster in the early stage,and the DOC content of pruned leaves was higher in the early stage.The humus like substances（fulvic acid like and humic acid like）in the DOC of the pruned leaves ranged from 52.9%to 64.4%,with obvious characteristics of plant origin.There are differences in the material composition characteristics of trimmed leaf DOC during the decomposition process,which affects the soil DOC composition.FD and CM217 exhibit significant microbial characteristics in both pruned leaf DOC and soil DOC.The humification index of DOC in CN pruned leaves ranges from 3.60 to 5.08,and the proportion of soil DOC molecular humus substances ranges from 61.77%to 71.44%,all of which have strong characteristics of plant origin,indicating that CN has more plant derived DOC retained in the soil to improve its soil active organic carbon level. |
PDF Full Text Request