| Camellia oleifera is one of the important woody edible oil tree species in China,with unsaturated fatty acid content up to 90%in the tea oil and known as "Oriental olive oil".However,low yield per area hindered the development of C.oleifera industry,how to increase the yield became a problem to solve urgently.Fertilizer which can ensure high yield and quality of crop played an irreplaceable role.In order to fertilize nationally,it's urgent to carry out the research on soil fertility quality and quality of tea oil.In this study,C.oleifera plantation soils were collected from 142 samples,site factors and biomass were investigated and Se-rich fertilization was carried out.28 soil properties and 11 tea oil quality indicators were determined.The dominant site factor and MDS were set by PCA.Then soil quality evaluation was carried out by the soil quality index,grey relational analysis and so on based on MDS.At the same time,the effects on tea oil quality characteristics of selenium fertilizer were discussed.The main results were as follows:(1)The study showed that parent material,slope position and soil texture were the dominant factors to affect the growth of C.oleifera forest.Parent material,slope position and soiltexture had the maximum load value in each PC with the vale of 0.940,0.820,0.815 base on PCA from seve site factors of altitude,slope position,slope direction,slope,parent materials,soil thickness and soil texture.The samples can be divided three types:slate,sandstone and quaternary red clay.(2)Significant differences were found in soils with different parent materials,soils derived from slate were rich nutrient content and strong enzyme activity,the contents of TN,AK,AMn,ACu,AZn,urease,sucrase and MBC were significantly higher than others,but the contents of AB were low.Soils derived from sandstone had high content of organic matter with the value of 30.93mg/kg,low content of AK(50.51mg/kg)and AMn(22.51mg/kg).Soils derived from quaternary red clay were nutrient deficiency,especially in the content of organic matter and TN,with the value of 15.07g/kg and 0.43g/kg.(3)CCA results showed that soil biological properties such as MBN,acid phosphatase,sucrase,catalase and urease were associated with soil nutrient,which should be candidate indicators of soil fertility quality evaluation.The correlation analysis showed that MBN,acid phosphatase,sucrase,catalase and urease had the longest arrows,which indicatedthey were significant correlation with soil nutrient.The MBC,MBP,actinomycetes,bacteria,which had the shortestarrows showed that they had no significant correlation with soil nutrients,and can be deleted from MDS.(4)The MDS of assessing soil quality were clay,SOM,AP,AK,AFe,AB,MBN acid phosphatase and fungi.9 indicators were select from 28 indicaors base on PCA,CCA and Norm.The results of soil fertility quality assessment were the same by MDS and 28 indicators,with R2>0.8,and the correlation coeffcient between results and yield was 0.712.(5)Soil fertility quality of different parent materials were as follows:slate>sandstone>quaternary red clay,with the SQI values of 0.731,0.573,0.405;NQI values of 0.469,0.357,0.265;and grey correlation degree of 0.710,0.647,0.521,respectively.(6)AP was the limiting factor for C.oleifera soils and SOM was the limiting factor for soils derived from quaternary red clay.The correlation coefficient of GRA showed that SOM were the maximum with the value of 0.769,then was AP with the value of 0.703.AP content in the areas was less than 10 mg/kg.So,AP may be the limiting main factor.SOM content in the soils derived from quaternary red clay which was significantly low than others may consided the linitign factor.(7)Selenium fertilizer can significantly increase the selenium content of tea oil,and reached 0.05 mg/kg of se-enriched tea oil standards.Application of selenium can significantly increase the selenium content ofnut,seed shell and kernel,8.49,10.86,10.04 times respectively than CK.The selenium content of tea oil also increased and would be up to 0.1254 mg/kg.(8)Selenium fertilizer could significantly improve the quality of tea oil,reduce peroxide value and acid value,and improve the squalene and tocopherol content.Compared with the CK,selenium treatment tea oil peroxide value can be reduced by 19.14%?19.14%,acid value fell by 20.56%?51.21%,tocopherol content can be increased by 22.13%?83.35%,squalene content increased by 1.63?3 times.PCA results showed that comprehensive score values of tea oil quality by application of selenium was higher than the CK. |
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