【作者】 林淑伟；

【导师】 吴承祯；

【作者基本信息】 福建农林大学 ， 生态学， 2009， 博士

【摘要】 凋落物的分解对生物地球化学循环起着重要的作用,是树木生长所需养分的重要来源,每年释放的营养可满足69%-87%的森林生长需要。长苞铁杉、南方铁杉、南方红豆杉、三尖杉、柳杉、水杉、福建柏都是起源古老的孑遗植物,为我国特有的国家级珍贵保护植物,现有资源甚少,具有重要的经济价值和研究价值。由于其生境特殊,一旦受到破坏,极难以恢复和更新,有沦为渐危状态的危险,其中凋落物难分解在一定程度上是限制种子发芽与幼苗生长的重要原因。可见,这7种针叶在其生态系统养分循环和自然更新中有着重要意义,因此,对其针叶分解进行探讨研究,建立针叶快速分解机制,促进营养物质的更新利用具有十分重大的意义。但目前仅零星见几篇柳杉、水杉和福建柏凋落物分解的报道,而对其他4种珍贵树种凋落物分解尚未见有关报道,而从内源物质和外源物质探讨凋落物分解的研究未见报道。本文采用野外分解袋法来研究外源物质(N肥、烟草秸秆)对7种珍贵树种针叶分解的影响,分5个处理水平来施加外源物质,即CK(对照)、N1(2.5gN肥)、N2(5gN肥)、JG1(10g烟草秸秆)、JG2(20g烟草秸秆)处理。首次提出采用氨化、碱化理念促进这7种珍贵树种针叶的分解,探讨外源物质(N肥、烟草秸秆)对内源物质(木质素、全N等)含量的影响,进而影响针叶分解速率,建立针叶快速分解的机制;并首次对应用烟草秸秆来实现促进森林凋落物分解的影响进行探讨,为秸秆的综合利用开辟一条新途径。同时,本文也第一次尝试用起伏型时间序列模型来对针叶分解过程的养分含量动态进行模拟,应用神经网络法及支持向量机法对针叶分解率与基质质量关系进行模拟预测,应用柯布-道格拉斯生产函数来建立外源物质对珍贵树种针叶分解的促进机制并进行敏感性分析,模拟及预测的效果比较理想。文章主要对7种珍贵树种的5个不同处理的针叶在13个月分解过程中的失重规律、养分动态和针叶分解与基质质量关系进行探讨,初步获得以下主要结果和结论:1.外源物质的添加在一定程度上促进了针叶的分解经过13个月的分解,长苞铁杉针失重率大小顺序为JG2>JG1>N2>N1>CK;南方铁杉针叶失重率大小顺序为JG2>CK>N1>JG1>N2;南方红豆杉针叶失重率大小顺序为JG2>CK>JG1>N2>N1;三尖杉针叶失重率排序为CK>JG2>N1>JG1>N2;水杉针叶失重率大小顺序为:JG2> N2>JG1>CK>N1;柳杉针叶失重率大小顺序为JG1>JG2>N2>CK>N1;福建柏针叶失重率大小顺序为JG2>JG1>CK>N1>N2。从整个分解过程看,跟对照针叶相比,基本上烟草秸秆处理的对针叶的分解促进作用相对比N肥处理的要明显,但从研究过程的早期分析,N肥处理的在早期对针叶的分解有显著的促进分解作用。在早期,添加外源N使针叶的C/N等基质质量发生变化、影响微生物活性及N矿化速率及硝化速率等,从而影响针叶的分解;在分解后期,木质素/N比对针叶分解影响更为重要,添加烟草秸秆在分解后期与针叶产生木质素碱化效应从而促进其分解。2.不同树种针叶基质质量不一样是导致相同处理针叶分解率不一样的主要原因经过13个月的分解,CK处理的不同树种针叶分解率排序为:三尖杉>南方铁杉>柳杉>水杉>南方红豆杉>福建柏>长苞铁杉;N1处理的不同树种针叶分解率排序为:三尖杉>柳杉>南方铁杉>水杉>福建柏>南方红豆杉>长苞铁杉;N2处理的不同树种针叶分解率排序为:水杉>柳杉>三尖杉>南方铁杉>长苞铁杉>南方红豆杉>福建柏;JG1处理的不同树种针叶分解率排序为:柳杉>水杉>三尖杉>南方铁杉>福建柏>南方红豆杉>长苞铁杉;JG2处理的不同树种针叶分解率排序为:水杉>南方铁杉>福建柏>三尖杉>南方红豆杉>柳杉>长苞铁杉。结果表明,不同树种针叶的分解率是不一样的,这与各树种针叶本身的基质质量有很大的关系;添加不同水平的外源物质对针叶分解的影响程度各不相同;但不同处理的分解率结果都表明,长苞铁杉针叶的分解率都是最低的,这与长苞铁杉针叶的质地有很大关系。3.除水热等环境条件对针叶分解有重要影响外,其他因素对针叶分解也起重要作用从月失重率分析,在分解的不同月份(2008年1月-12月)都出现过月失重率的高峰值,对大部分树种和处理而言,5-11月份出现月失重率的高峰值比较多,此时正值研究区研究期的高温多雨天气,说明分解过程中水热等环境条件对不同树种针叶的分解有很大程度的影响;但在取样的不同月份不同树种、不同处理也出现过月失重率的最低值,说明影响针叶分解的除水热条件外还有其他影响因子。另外,在分解的第6-9个月即2008年的5-8月份在分解袋里发现较大型的土壤动物蚯蚓、蚂蚁等,很显然土壤动物及微生物对针叶的分解也相当程度的影响。4.不同处理不同树种的分解率在分解过程中总体差异显著对不同处理不同树种的分解率动态进行方差分析,结果表明,不同树种间、不同外源水平处理间、不同时间的分解率差异都比较显著,且不同树种与处理间、树种与时间间、处理与时间间的交互作用的分解率方差分析差异也显著,说明不同树种的分解速率是不一样的,不同水平的外源物质对针叶分解的影响也是不同而且效果显著,分解速率随时间变化是明显的,而且不同树种与处理间、树种与时间间、处理与时间间的交互作用对针叶的分解影响也是显著的。分析结果也进一步表明可以利用外源N肥和烟草秸秆来促进珍贵树种针叶分解,对珍贵树种针叶物质营养循环、更新利用和珍贵树种生产力的长期维护以及烟草秸秆的利用具有一定的实践意义。5.在分解过程中,不同养分含量变化规律不同,同一元素在不同树种针叶和不同处理间的含量变化也不一致对7种珍贵树种针叶的5个不同处理的分解过程的C、N、P、K、Na、Ca、Mg、Zn和Mn和木质素进行研究分析,分析结果显示,不同养分含量、释放量、净释放量、残留率及净释放率在整个分解过程基本上都呈升-降-升-降的起伏型变化趋势。其中,N、Mn经过13个月的分解含量都比初始高,呈富集状态,K、Na的含量基本呈持续下降趋势,其他元素在分解过程及经过13个月的分解时都出现不同程度的释放和富集。经过13个月的分解,除长苞铁杉和南方铁杉针叶外,其他5种针叶的不同处理的C含量都出现下降;不同处理的P含量在长苞铁杉、南方红豆杉、水杉和福建柏针叶分解过程呈下降趋势;不同处理的Ca含量在长苞铁杉、南方铁杉和水杉针叶经过13个月分解呈富集状态;不同处理的Mg含量在长苞铁杉和南方铁杉针叶经过13个月分解呈富集状态,在水杉针叶中呈释放状态;不同处理的Zn含量除福建柏针叶外都呈富集状态。经过13个月的分解,基本上,在长苞铁杉、南方铁杉和三尖杉针叶中,外源处理的C含量都比CK处理要高,除三尖杉针叶外,N肥处理的C含量比烟草秸秆处理的高;南方红豆杉针叶的C含量:烟草秸秆处理>CK处理>N肥处理;水杉、柳杉、福建柏针叶中,CK处理的C含量比外源处理的要高,烟草秸秆处理的含量高于N肥处理的。在长苞铁杉、南方铁杉、三尖杉和水杉针叶中,外源处理的N含量都比对照要高,除长苞铁杉针叶外,N肥处理的N含量比烟草秸秆处理的高;南方红豆杉和福建柏针叶中CK处理的N含量比外源处理的高;柳杉针叶的N含量:N肥处理>CK处理>烟草秸秆处理。7种针叶的P含量CK处理的含量都高于外源处理的,长苞铁杉、南方铁杉、水杉、柳杉针叶N肥处理的P含量比烟草秸秆处理的高。经过13个月的分解,基本上,除三尖杉针叶的K含量为:烟草秸秆处理>CK>N肥处理外,其他针叶的K含量CK处理大于外源处理。Na含量,N肥处理的高于烟草秸秆处理的,CK处理的居中。Ca含量烟草秸秆处理的含量高于N肥处理的,南方红豆杉、三尖杉和福建柏针叶CK处理的含量高于外源处理的,水杉针叶CK处理的含量低于外源处理,而其他针叶CK处理含量居中。长苞铁杉、南方铁杉和柳杉针叶的Mg含量CK处理大于外源处理,其他针叶CK处理的Mg含量居中,且基本上烟草秸秆处理的Mg含量大于N肥处理的。经过13个月的分解,基本上,Zn含量在长苞铁杉、南方铁杉、南方红豆杉和柳杉针叶中,CK处理的大于外源处理的,在三尖杉针叶中,CK处理的Zn含量居中,且基本上都是N肥处理的高于烟草秸秆处理的;在水杉和福建柏针叶中,外源处理的含量大于CK处理的,烟草秸秆处理的含量高于N肥处理的。Mn含量在长苞铁杉、三尖杉和福建柏针叶中,外源处理的含量大于CK处理的,南方铁杉、南方红豆杉和柳杉针叶中,CK处理的大于外源处理的,水杉针叶中,CK处理的含量居中,除南方铁杉和柳杉针叶外基本上都是烟草秸秆处理的含量高于N肥处理的。经过13个月的分解,基本上,木质素含量在长苞铁杉和南方红豆杉针叶中,CK处理的大于外源处理的,而在其他针叶中基本上都是外源处理的含量大于CK处理的,且在南方红豆杉、三尖杉和福建柏针叶中,烟草秸秆处理的含量高于N肥处理的。可见,添加外源物质对不同针叶、不同元素的含量变化的影响是不同的。6.不同针叶的分解率与不同基质质量指标关系不同,但基本上与N含量呈线性正相关,与C/N比、木质素/N呈线性负相关长苞铁杉针叶的分解速率与N含量、C/P比、Ca含量呈线性正相关,与P含量、C/N比、木质素/N呈线性负相关。南方铁杉针叶的分解速率与N含量、P含量呈线性正相关,与C/N比、C/P比、木质素/N比和Ca含量呈线性负相关。南方红豆杉针叶的分解速率与N含量、C/P比、木质素、Ca含量呈线性正相关,与C/N比、P含量、木质素/N比呈线性负相关。三尖杉针叶的分解速率与N含量、木质素含量呈线性正相关,与C/N比、木质素/N比呈线性负相关。水杉针叶的分解速率与N含量、Ca含量呈线性正相关,与C/N比、P含量和木质素/N比呈线性负相关。柳杉针叶分解率与N含量呈非常显著的线性正相关,与C/N比呈非常显著的线性负相;与N1处理的P含量呈显著的线性正相关,与JG2处理的P含量呈非常显著的线性负相关;与JG1处理的C/P呈显著的线性负相关,与JG2处理的C/P呈显著线性正相关;与木质素含量呈线性正相关;柳杉针叶分解率与木质素/N呈线性负相关。福建柏针叶分解速率与N含量、C/P、Ca含量呈线性正相关,与C/N比、P含量和木质素/N比呈线性负相关。对7种珍贵树种针叶的分解率(y)与基质质量(C、N、P、木质素、Ca含量)进行多元线性回归分析,分析结果表明,无论是对5个不同处理的7种珍贵树种针叶的分解率与基质质量的多元线性回归还是不分处理对总体所进行的多元线性回归分析,结果都表明,所建立的多元线性回归模型比较理想,相关系数较高且线性相关性都非常显著(p<0.01),7种珍贵树种针叶的分解率都与C和P含量呈负相关,与N、木质素和Ca含量呈线性正相关。CK处理的7种树种针叶的分解常数(k)与初始C、N、P、K、Na、Ca和Mg含量呈正相关,与初始Zn、Mn、木质素含量和木质素/N、C/N及C/P比呈负相关。其中,分解常数与木质素含量呈显著线性负相关(P=0.02201<0.05),与木质素/N比呈非常显著线性负相关(P=0.0086<0.01)。7.建立的外源物质对珍贵树种针叶分解的促进机制表明,减少外源N肥的施加量或增加烟草秸秆的施加量都能促进针叶的分解以7个树种为总体,应用多元线性回归模型和柯布-道格拉斯生产函数来建立分解常数与外源物质之间的关系,即,外源物质对珍贵树种针叶分解的促进机制,结果表明,不同树种针叶分解常数与外源N呈非常显著线性负相关,与外源烟草秸秆呈非常显著线性正相关,即减少外源N肥的施加量或增加烟草秸秆的施加量都能促进针叶的分解,这与研究期结束时不同树种不同处理的分解率结果基本相符;柯布-道格拉斯生产函数边际效应分析表明,在现有条件下,当其他条件不变,每增加1gN肥,针叶分解常数就减少0.0034;每增加1g烟草秸秆,针叶分解常数就增加0.0025。但在研究过程中,对不同处理的针叶分解率的分析表明,施加N肥对早期针叶的分解也起到积极的促进分解的作用。更多还原

【Abstract】 Litter decomposition plays an important role in biogeochemical cycling. The nutrients it released is an important nutrient resources for trees’growth and would provide 69%-87% nutrients needed by forest growth. Tsuga longibracteata, Tsuga Tchekiangensis, Taxus chinensis var. mairei,Cephalotaxus fortunei, Cryptomeria fortunei Hooibrenk ex Otto et Dietr, Metasequoia glyptostroboides Hu et Cheng, Fokienia hodginsii(Dunn)Henry et Thomas are ancient relic plants which are precious rare endemic national protected species and have important values on economic and research. Due to their special habitats, once the species destroyed, they were hard to restored and would be in endangered. The hard decomposition of litter fall was one of the important limiting reason for seeds germination and seedling growth to a certain extent, which means that the conifer leaves played important roles in ecological nutrients cycling and their natural regeneration. Therefore, it is very important to study their leaves decomposition and establish a fast decomposition mechanism in order to promote nutrients recycling use. But up to now, there were hardly any report about the decomposition of the 7 conifer leaves except a few papers on Cryptomeria fortunei Hooibrenk ex Otto et Dietr, Metasequoia glyptostroboides Hu et Cheng and Fokienia hodginsii(Dunn)Henry et Thomas leaves, and there is no report to study the 7 conifer leaves decomposition in the view of endogenous and exogenous substances.The effects of exogenous substance on precious conifer leaves decomposition were studied by nylon bags method with 5 different treatments: CK(contrast), N1(2.5g nitrogen fertilizer),N2(5.0g nitrogen fertilizer), JG1(10g tobacco straw), JG2 (20g tobacco straw). Ammoniation and alkalization concepts were first put forward to promote decomposition of the precious conifer leaves and to study the effects of exogenous substances (nitrogen fertilizer, tobacco straw) on endogenous substances (lignin, nitrogen and ect ),which would thereby affect conifer leaves decomposition, and to establish conifer leaves fast decomposition mechanism. Tobacco straw was firstly added to forest litter to promote litter decomposition which explored a new way for tobacco straw comprehensive utilization. And in this paper, wave-type time series model was firstly applied to simulate the dynamic nutrient contents of conifer leaves. The conifer leaves decomposition ratios were simulated and predicted by applying neural network method and support vector machine method to analyse the relationship between conifer leaves decomposition ratios and substrate qualities for the first time. Cobb-Douglas production function was also firstly applied to establish the conifer leaves decomposition mechanism by analysing the effects of exogenous substance on conifer leaves decomposition, and the sensitivity was analyzed basing on the decomposition mechanism. The results showed that the simulated and predicted effects of those model were acceptable. In this paper, the weight loss regularity, nutrient dynamics and the relationships between the conifer leaves decomposition and their substrate qualities were mainly discussed for 7 conifer leaves with 5 different treatments under 13-month decomposing, the results and conclusions were as follows:1.Adding exogenous substances promoted the conifer leaves decomposition to different degrees.After 13-month decomposing, the weight loss ratios order of Tsuga longibracteata leaves was: JG2>JG1>N2>N1>CK; the weight loss ratios order of Tsuga Tchekiangensis leaves was: JG2>CK>N1>JG1>N2;the weight loss ratios order of Taxus chinensis var. mairei leaves was: JG2>CK>JG1>N2>N1;the weight loss ratios order of Cephalotaxus fortunei leaves was: CK>JG2>N1>JG1>N2;the weight loss ratios order of Metasequoia glyptostroboides Hu et Cheng leaves was:JG2>N2>JG1>CK>N1; the weight loss ratios order of Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves was: JG1>JG2>N2>CK>N1;the weight loss ratios order of Fokienia hodginsii(Dunn)Henry et Thomas leaves was: JG2>JG1>CK>N1>N2.As a whole, compared to CK treatment, the tobacco straw treatments had more influence on conifer leaves’decomposition than nitrogen fertilizer treatments did basically, however, nitrogen fertilizer treatments greatly promoted leaves decomposition in the early stage. The possible reason was that adding nitrogen fertilizer would cause changes of substrate qualities such as C/N ratios which would affect microbial activities and mineralization and nitrification rate of nitrogen, and ect, and therefore affected the conifer leaves decomposition in the early stage. But in later stage, lignin nitrogen ratios had more influence on conifer leaves decomposition, and adding tobacco straw to conifer leaves would generate alkalinization effect, therefore promoted conifer leaves decomposition.2.Various conifer leaves had different substrate qualities which were the main causes of different decomposition ratios of conifer leaves under the same treatment.After 13-month decomposing, the decomposition ratios order of conifer leaves under CK treatment was: Cephalotaxus fortunei>Tsuga Tchekiangensis>Cryptomeria fortunei Hooibrenk ex Otto et Dietr>Metasequoia glyptostroboides Hu et Cheng>Taxus chinensis var. mairei>Fokienia hodginsii(Dunn)Henry et Thomas > Tsuga longibracteata; the decomposition ratiosorder under N1 treatment was: Cephalotaxus fortunei>Cryptomeria fortunei Hooibrenk ex Otto et Dietr>Tsuga Tchekiangensis>Metasequoia glyptostroboides Hu et Cheng>Fokienia hodginsii(Dunn)Henry et Thomas>Taxus chinensis var. mairei>Tsuga longibracteata; the decomposition ratios order under N2 treatment was: Metasequoia glyptostroboides Hu et Cheng> Cryptomeria fortunei Hooibrenk ex Otto et Dietr > Cephalotaxus fortunei > Tsuga Tchekiangensis > Tsuga longibracteata > Taxus chinensis var. mairei > Fokienia hodginsii(Dunn)Henry et Thomas; the decomposition ratios order under JG1 treatment was: Cryptomeria fortunei Hooibrenk ex Otto et Dietr>Metasequoia glyptostroboides Hu et Cheng>Cephalotaxus fortunei>Tsuga Tchekiangensis>Fokienia hodginsii(Dunn)Henry et Thomas>Taxus chinensis var. mairei>Tsuga longibracteata; the decomposition ratios order under JG2 treatment was: Metasequoia glyptostroboides Hu et Cheng>Tsuga Tchekiangensis>Fokienia hodginsii(Dunn)Henry et Thomas > Cephalotaxus fortunei > Taxus chinensis var. mairei > Cryptomeria fortunei Hooibrenk ex Otto et Dietr>Tsuga longibracteata. The results showed that different conifer leaves had different decomposition ratios which had much to do with their substrate qualities. Different exogenous substances had different influences on the conifer leaves decomposition ratios, but the results showed that Tsuga longibracteata leaves had the lowest decomposition ratios under each treatment which had much to do with its texture.3.Beside environmental conditions such as water and heat, other factors also played important roles in conifer leaves decomposition.By analysing monthly weight loss ratio, the results showed that peak values of weight loss ratio appeared in every month(Jan-Dec 2008) either in different leaves or under different treatments. But for most conifer leaves and treatments, May-Nov emerged more peak values than other periods when it was hot and rainy, which indicated that environmental conditions, such as water and heat had great influences on decomposition. But the lowest decomposition ratios values also appeared in every month among different conifer leaves or treatments which indicated that beside the water and heat, other factors also had great influences on conifer leaves decomposition. Beside, angleworms and ants were found in the nylon bags among May-Aug,2008, which indicated that soil animals and microorganism also played important roles in leaves decomposition.4.Conifer leaves decomposition ratios were significant different among various treatments and different conifer leaves during decomposing process.The results of ANOVA of dynamic decomposition ratios of 7 precious conifer leaves under various treatments showed significant differences among different conifer leaves, various treatments, periods. And the differences also emerged between specie and treatment, specie and period, treatment and period which indicated that different species had different decomposition ratios, various treatments had different effects on conifer leaves decomposition and the results were distinct, decomposition ratios changed by the time, and interactions between species and treatments, species and periods, treatments and periods had great influences on conifer leaves decomposition. The results also indicated that it was practically viable to use exogenous nitrogen fertilizer and tobacco straw to accelerate conifer leaves decomposition, which had practical significances on nutrients cycling and reusing, precious rare trees’long-term productivity maintaining and tobacco straw’s utilization.5. During decomposing process, different nutrient contents had different change regularities, the change regularities of the same nutrient content were different among different conifer leaves and treatmentsBy analyzing the carbon, nitrogen, phosphorus, kalium, natrium, calcium, magnesium, zinc, manganese and lignin of 7 conifer leaves under 5 treatments, the results showed that the change tendencies of nutrient content, release, net release, remaining ratio and net releasing ratio were in fluctuant styles. After 13-month decomposing, the contents of nitrogen and manganese were higher than initial contents which were in enrichment state, kalium and natrium contents decreased continuously, other nutrients were either in release state or in enrichment state to various degrees during decomposing process.After 13-month decomposing, except Tsuga longibracteata and Tsuga Tchekiangensis leaves, the carbon contents of other 5 conifer leaves decreased in various treatments. The phosphorus contents decreased in Tsuga longibracteata leaves, Taxus chinensis var. mairei leaves, Metasequoia glyptostroboides Hu et Cheng leaves and Fokienia hodginsii (Dunn) Henry et Thomas leaves under various treatments during decomposing process. The calcium contents were in enrichment state in Tsuga longibracteata leaves, Tsuga Tchekiangensis leaves and Metasequoia glyptostroboides Hu et Cheng leaves after 13-month decomposing. The magnesium contents were in enrichment state in Tsuga longibracteata leaves and Tsuga Tchekiangensis leaves after 13-month decomposing, but were in releasing state in Metasequoia glyptostroboides Hu et Cheng leaves. The zinc contents were all in enrichment state except Fokienia hodginsii (Dunn) Henry et Thomas leaves.After 13-month decomposing, in Tsuga longibracteata leaves, Tsuga Tchekiangensis leaves and Cephalotaxus fortunei leaves, the carbon contents were higher in exogenous substances treated leaves than CK treated leaves, and except Cephalotaxus fortunei leaves, the carbon contents were higher in nitrogen fertilizer treated leaves than in tobacco straw treated leaves, the carbon contents order of Taxus chinensis var. mairei leaves was: tobacco straw treatments > CK treatment > nitrogen fertilizer treatments, in Metasequoia glyptostroboides Hu et Cheng leaves, Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves and Fokienia hodginsii(Dunn)Henry et Thomas leaves, the carbon contents were higher in CK treated leaves than in exogenous substances treated leaves, the carbon contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves. In Tsuga longibracteata leaves, Tsuga Tchekiangensis leaves, Cephalotaxus fortunei leaves and Metasequoia glyptostroboides Hu et Cheng leaves, the nitrogen contents were higher in exogenous substances treated leaves than CK treated leaves, except Tsuga longibracteata leaves, the nitrogen contents were higher in nitrogen fertilizer treated leaves than in tobacco straw treated leaves, in Taxus chinensis var. mairei leaves and Fokienia hodginsii(Dunn)Henry et Thomas leaves, the nitrogen contents were higher in CK treated leaves than in exogenous substances treated leaves, the nitrogen contents order of Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves was: nitrogen fertilizer treatments > CK treatment > tobacco straw treatments. For 7 conifer leaves, the phosphorus contents were higher in CK treated leaves than in exogenous substances treated leaves, and in Tsuga longibracteata leaves,Tsuga Tchekiangensis leaves,Metasequoia glyptostroboides Hu et Cheng leaves and Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves, the phosphorus contents were higher in nitrogen fertilizer treated leaves than in tobacco straw treated leaves.After 13-month decomposing, except in Cephalotaxus fortunei leaves,the kalium contents order was: tobacco straw treatments > CK treatment > nitrogen fertilizer treatments, in other conifer leaves, the kalium contents were higher in CK treated leaves than in exogenous substances treated leaves. For natrium contents, the contents were higher in nitrogen fertilizer treated leaves than in tobacco straw treated leaves, the contents were higher in CK treated leaves than in tobacco straw treated leaves. For calcium contents, the contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves, the contents of CK treated leaves were in the middle of them. In Tsuga longibracteata leaves, Tsuga Tchekiangensis leaves and Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves, the magnesium contents were higher in CK treated leaves than in exogenous substances treated leaves, but for other leaves, the magnesium contents of CK treated leaves were in second place, and basically, the magnesium contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves.After 13-month decomposing, basically, in Tsuga longibracteata leaves, Tsuga Tchekiangensis leaves, Taxus chinensis var. mairei leaves and Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves, the zinc contents were higher in CK treated leaves than in exogenous substances treated leaves, in Cephalotaxus fortunei leaves, the contents of CK treated leaves were between tobacco straw treated leaves and nitrogen fertilizer treated leaves, and basically, the contents were higher in nitrogen fertilizer treated leaves than in tobacco straw treated leaves, in Metasequoia glyptostroboides Hu et Cheng leaves and Fokienia hodginsii(Dunn)Henry et Thomas leaves, the contents were higher in CK treated leaves than in exogenous substances treated leaves, and the contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves. For manganese contents, the contents were higher in exogenous substances treated leaves than in CK treated leaves in Tsuga longibracteata leaves,Cephalotaxus fortunei leaves and Fokienia hodginsii(Dunn)Henry et Thomas leaves, in Tsuga Tchekiangensis leaves, Taxus chinensis var. mairei leaves and Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves, the contents were higher in CK treated leaves than in exogenous substances treated leaves, in Metasequoia glyptostroboides Hu et Cheng leaves, the contents of CK treated leaves were between tobacco straw treated leaves and nitrogen fertilizer treated leaves, except Tsuga Tchekiangensis leaves and Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves, the contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves basically.After 13-month decomposing, basically, in Tsuga longibracteata leaves and Taxus chinensis var. mairei leaves, the lignin contents were higher in CK treated leaves than in exogenous substances treated leaves, but in other conifer leaves, the lignin contents were higher in exogenous substances treated leaves than in CK treated leaves, and in Taxus chinensis var. mairei leaves, Cephalotaxus fortunei leaves and Fokienia hodginsii(Dunn)Henry et Thomas leaves, the contents were higher in tobacco straw treated leaves than in nitrogen fertilizer treated leaves. The result showed that adding exogenous substances had different impacts on the nutrient contents of different conifer leaves and different nutrients.6.Different conifer leaves decomposition ratios had different relationships with different substrate qualities, but basically had positive linear correlativity with nitrogen content, and had negative linear correlativity with carbon nitrogen ratio and lignin nitrogen ratio The decomposition ratios of Tsuga longibracteata leaves had positive linear correlativity with nitrogen contents, carbon phosphorus ratios and calcium contents, and had negative linear correlativity with phosphorus contents, carbon nitrogen ratios and lignin nitrogen ratios. Tsuga Tchekiangensis leaves decomposition ratios had positive linear correlativity with nitrogen content s and phosphorus contents, and had negative linear correlativity with carbon nitrogen ratios, carbon phosphorus ratios, lignin contents and calcium contents. Taxus chinensis var. mairei leavesdecomposition ratios had positive linear correlativity with nitrogen contents, carbon phosphorus ratios, lignin contents and calcium contents, and had negative linear correlativity with carbon nitrogen ratios phosphorus contents and lignin nitrogen ratios. Cephalotaxus fortunei leaves decomposition ratios had positive linear correlativity with nitrogen contents and lignin contents, and had negative linear correlativity with carbon nitrogen ratios and lignin nitrogen ratios Metasequoia glyptostroboides Hu et Cheng leaves decomposition ratios had positive linear correlativity with nitrogen contents and calcium contents, and had negative linear correlativity with carbon nitrogen ratios, phosphorus contents and lignin nitrogen ratios. Cryptomeria fortunei Hooibrenk ex Otto et Dietr leaves decomposition ratios had a distinctly positive linear correlativity with nitrogen contents, and had a distinctly negative linear correlativity with carbon nitrogen ratios, and had a distinctly positive linear correlativity with phosphorus contents in N1 treated leaves, and had a distinctly negative linear correlativity with phosphorus contents in JG1 treated leaves; had a distinctly negative linear correlativity with carbon phosphorus ratios in JG1 treated leaves; had positive linear correlativity with lignin contents; had negative linear correlativity with lignin carbon ratios. Fokienia hodginsii(Dunn)Henry et Thomas leaves decomposition ratios had positive linear correlativity with nitrogen contents, carbon phosphorus ratios and calcium contents, and had negative linear correlativity with carbon nitrogen ratios, phosphorus contents and lignin nitrogen ratios.The result of multilinear regression analysis about 7 precious conifer leaves decomposition ratios and substrate qualities(carbon content ,nitrogen content, phosphorus content, lignin content and calcium content ) showed that, whether analyzing every single treatment or as a whole, the multilinear regression models were satisfactory, and correlative coefficients were high and the linear relationships were very distinct. 7 precious conifer leaves decomposition ratios had negative linear correlativity with carbon contents and phosphorus contents, and had positive linear correlativity with nitrogen contents, lignin contents and calcium contents.In CK treatment, 7 precious conifer leaves decay constants (k) had positive correlativity with initial carbon contents, nitrogen contents, phosphorus contents, kalium contents, natrium contents , calcium contents and magnesium contents, and had negative linear correlativity with initial zinc contents, manganese contents, lignin contents, lignin nitrogen ratios, carbon nitrogen ratios and carbon phosphorus ratios. Among them, decay constant (k) had a distinctly negative correlativity with initial lignin contents, and had a very distinctly negative correlativity with initial lignin nitrogen ratios.7.Conifer leaves decomposition promoting mechanism established by analyzing the effect of exogenous substances on conifer leaves decomposition showed that reducing exogenous nitrogen fertilizer or increasing exogenous tobacco straw would accelerate conifer leaves decomposition The relationship of decay constant and exogenous substances was established by multilinear regression model and Cobb-Douglas production function treating 7 conifer leaves as a whole, which indicated that decay constant had a very distinctly negative correlativity with exogenous nitrogen fertilizer treatments, and had a very distinctly positive correlativity with exogenous tobacco straw treatments, namely, reducing exogenous nitrogen fertilizer or increasing exogenous tobacco straw would accelerate conifer leaves decomposition. The result matched with the decomposition ratios of different species under various treatments. Marginal analysis of Cobb-Douglas production function showed that ,on current conditions, other conditions being equal, decay constant would decrease 0.0034 by adding 1g nitrogen fertilizer and increase 0.0025 by adding 1g tobacco straw. However, the analysis of conifer leaves decomposition during the decomposing process showed that adding nitrogen fertilizer to conifer leaves had accelerated the decomposition in early stage.更多还原