| Arborvitae plantation is the main forest types in the hilly region of Sichuan basin. Affected by climate, soil, hydrology etc. and the low level of management, the forest grew slowly and loses its balancement. The stand productivity and the ecological benefit were extremely low. The economic income of the local forest workers suffered. So, by selection of tree species, improvement of site conditions, adjustment of stand structure, raising level of operation and management etc. were the main approach of the transformation of the low-efficiency forest of cypress in the local area. This paper used correlation analysis, DRIS, adding soil nutrient analysis and nutrient use efficiency to diagnosed the plantation of Platycladusorientalis(L.)Franco at Ba Jiao Jing town in Jing Yang district in De Yang city, and understood the supply situation of the nutrition of Platycladusorientalis(L.)Franco, and selected out the nutrient limiting factor, and built up the diagnosis standard, and provided the theoretical basis for the improvement of the level of nutrition management of Platycladusorientalis(L)Franco and of the stand productivity, the research conclusions as follows:(1)Correlation analysis showed that the stand yield and stand density uncorrelated, nutrient concentration of total P, exchangeable Mg, available K in the soil and nutrient concentration of Mg, Fe in the leaves have a significant positive correlation with stand yield.(2)Combined with different stand yield, use the nutrient diagnosis method of DRIS, selected out the foliar nutrition indexes for diagnosis, the conclusions were:the diagnose indexes of stand average height were P、K、P/K、K/N、K/P、K/Fe、K/Cu、K/S、Ca/N、 Ca/P、Mg/N etc. summing to 28 indexes; the diagnose indexes of stand dominate height were P、N/Mn、N/Zn、P/Fe、K/N、K/P、K/Fe etc. summing to 21 indexes; the diagnose indexes of individual volume were N、N/Cu、P/Ca、K/N、K/P、K/Fe、K/S、Ca/P etc. Summing to 32 indexes; the diagnose indexes of average diameter at breast height were N/P、P/Ca、P/Mg、P/Cu、K/N、K/P、K/Ca、K/Mg、K/Fe、K/S、Ca/P etc, summing to 13 indexes; the diagnose indexes of stand volume were N/Fe、N/Mn、N/Zn、K/N、 K/P、K/Fe、Ca/K、Fe/N、Fe/Zn、Mn/N、Mn/Mg etc, Summing to 18 indexes.(3)By calculating diagnostic indexes, built up the diagnostic standard of different nutrient elements, and through comprehensive comparison, we got the proper foliar nutrient concentration scope of plantation of Platycladusorientalis(L.)Franco, they were, N:8.43～17.31g/kg, P:0.63～0.86g/kg, K:3.16～4.85g/kg, Ca:1.04～1.50g/kg, Mg:0.28～0.62g/kg, Fe:0.54～1.01g/kg, S:1.49～2.46g/kg, Cu:9.95～12.11mg/kg, Mn:43.15～103.75mg/kg,Zn:5.46～14.39mg/kg.(4)Soil nutrients analysis results showed that the soil of Arborvitae plantation presented alkaline, the range of pH among 7.50～8.18. the concentration of Exchangeable Ca was extremely high, and total N, available N, total K, available K were on the level of high or middle degree, total P, available Mg were on the level of extremely low degree, the organic matter was on the level of middle or low degree.(5)The conclusion of foliar nutrition use efficiency showed that Mg, Fe, P were the main nutrition elements that restricted growing of stands, Zn, Cu were the potential restricted elements, the sequence of the nutrition use efficiency of major and medium elements were:Mg>Fe>P>Ca>S>K>N, the sequence of the nutrition use efficiency of trace elements were:Zn>Cu>Mn.(6)By using different diagnostic approach to diagnose the plantation of Platycladus orientalis(L.)Franco, the comprehensive conclusion was:Mg, Fe, P, K, Cu were the main elements that influence the stand yield. So, managing the plantation should pay much attention to make fertilization measurement for Mg, Fe, P, K, and Cu, so as to promote the elements’ absorption of plantation and promote the yield increase. |
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