胶园间种对枯落物、腐殖质和土壤性质的影响

橡胶间种砂仁、咖啡对林地枯落物、腐殖质和土壤性质的影响调查结果表明，作物的间种明显提高了林地枯落物的积累量，橡胶＋砂仁、橡胶＋咖啡、纯橡胶林分别为３６５３．５、２８６１．１、１９３４．３ｋｇ／ｈｍ２；土壤有机质含量随之提高，０～５ｃｍ土层有机质含量分别为４４．３０３、３２．９０５、２６．８４０ｇ／ｋｇ；三种胶园种植模式土壤腐殖质组成均以富里酸为主，间种砂仁、咖啡利于胡敏酸和胡敏素的形成；土壤性状因间种而得到改良，２～５ｍｍ最为良好稳定的多孔性团粒结构含量分别为３０．８９％、１３．６６％和１２．１３％。以橡胶间种砂仁对土壤肥力的提高最为理想。     

橡胶间种砂仁、咖啡对土壤肥力的影响*

橡胶间种砂仁、咖啡对土壤肥力的影响杨曾奖，郑海水，尹光天，周再知，陈土王，陈康泰关键词橡胶，砂仁，咖啡，胶园间种，土壤肥力地处雷州半岛东海岸的南华农场，在胶园立体种植多层次栽培模式上进行了探索。１９７５年以来，由于逐步发展壳砂仁、咖啡等经济作物，至目...     

西双版纳砂仁种植模式探讨

简述国内现有的砂仁种植模式,并对主要模式的优缺点进行比较分析,认为热带雨林+砂仁模式对热带雨林物种多样性保护等带来严重的负面影响;各类杂木次生林+砂仁可在一定程度上提高砂仁产量; 杉木+砂仁、橡胶+砂仁种植模式具有改善土壤肥力、促进间种树种生长等优势。西双版纳有着相当数量的次生林、橡胶林、竹林等,把砂仁种植从热带雨林中转移到雨林外种植同样具有很大的资源优势和生产潜力。     

橡胶与砂仁间作复合生态系统营养元素循环的研究

橡胶与砂仁间作和纯橡胶林两种林分营养元素净积累、归还及营养元素在植物、土壤之间生物循环的研究结果表明：间种砂仁可明显增加林分植物库中营养元素的含量，间作林中营养元素总积存量达３４４７．０７ｋｇ／ｈｍ２，是纯胶林的２．５３倍；营养元素总归还量每年每公顷为３６３．２６ｋｇ，是纯胶林的１．４４倍，其中Ｎ，Ｐ，Ｋ，Ｃａ，Ｍｇ的年归还量分别是纯胶林的１．９，２．５４，１．４２，１．０５，１．１６倍；间作林中的Ｎ的归还量为最大，纯胶林中以Ｃａ的归还量为最大，两种林分均以Ｐ的归还量为最小。间作林中营养元素的年吸收总量为１０８３．４３ｋｇ／ｈｍ２，是纯胶林的２．１倍。尽管营养元素的循环系数低于纯胶林，但吸收系数却高于纯胶林，可见间种有利于植物对土壤库中营养元素的吸收。     

小良热带人工混交林的凋落物研究

研讨了小良热带人工混交林１０年的凋落量及其季节和年际动态，并对其现存凋落量进行了初步研究，结果表明：小凋落物总量年均为５．５３９ｔ／ｈｍ＾２；凋落量的季节变化明显，一般以湿季的７月为凋落高峰；少于其年均凋落量，处于分解大于积聚的周转过程中。     

沿海沙地吊丝竹林凋落物及养分动态研究

对沿海沙地吊丝竹林的凋落物及养分月动态特征进行连续观测分析,研究结果表明:竹林凋落物量月动态呈现双峰型模式,2个峰值分别出现在2004年10月和2005年4月,这2个月凋落物量占全年总量的26.90%;2005年1月和7月凋落物量较少,只占全年总量的8.92%。各营养元素在凋落物中组分平均值大小排列顺序为:N>K>P>Mg>Ca。凋落物N、P、K、Mg归还量月动态全年呈现出2个峰值期,分别出现在2004年10~11月和2005年4~5月;Ca只有单峰值期,出现在2004年10~11月。凋落物各营养元素归还量最大是N,年归还总量为58.32 kg.hm-2,最小是Ca,只有0.61 kg.hm-2。N、P、K、Mg、Ca在峰值期养分归还量分别占全年比例的48.44%、47.12%、50.48%、53.49%和36.30%。沿海沙地吊丝竹林凋落物年养分归还量为97.54 kg.hm-2。     

紫胶园生物群落的研究*

1987－1989年，在云南镇源热区研究紫胶园生物群落与环境的关系，群落内种间的相互影响；紫胶园间种粮食作物的作用，不同群落结构与产量、产值的关系，结果表明；胶粮间作群落、乔灌混交群落，能较好地利用自然种间的有利关系，使群落的经济产品总量较对照提高2．4－4．4倍，产值较对照提高1．9－2．0倍。     

不同龄组马尾松林凋落物量及养分归还量研究

对不同龄组马尾松人工林的年凋落物量、林地凋落物现存量及其元素含量和养分归还量进行分析测定，结果表明，从幼龄林至成熟林，马尾松林的年凋落物量为４．３９～１１．４３ｔ／ｈｍ２，林地凋落物现存量为４．９９～１３．４５ｔ／ｈｍ２，凋落物养分的年归还量为８７．７４～３５３．７１ｋｇ／ｈｍ２，林地凋落物养分的总贮量为１０１～２４８ｋｇ／ｈｍ２．这说明森林凋落物是一个庞大的养分贮存库，它对于维护林地地力，提高森林生产力具有重要的意义．     

木麻黄防护林生态系统凋落物及养分释放研究

运用定位研究的方法 ,在福建惠安赤湖林场定期收集木麻黄林分的凋落物 ,开展凋落物分解试验 ,并研究了木麻黄防护林的养分释放规律。结果表明 :( 1 )沿海木麻黄防护林 2 0a和 7a林分的凋落物年产量分别为 1 3 973和 1 2 3 85t·hm- 2 a- 1 ;( 2 )在凋落物分解过程中 ,木麻黄凋落物的失重率随时间而变化 ,其相互关系可用方程式W =-0 0 3 2 6t3+0 5 465t2 +2 1 5 41t+0 865 7来表达 ;( 3 )在不同林龄林分中 ,2 0a林分凋落物及其各组分中养分元素的含量高于 7a林分 ;同一林分中 ,元素种类不同 ,它们在凋落物各组分中的含量差别较大 ;( 4 ) 7a和 2 0a木麻黄林分每年归还给林地的养分总量为 2 5 0 2 4和 2 80 2 5kg·hm- 2 a- 1 ;( 5 )木麻黄凋落物分解的半衰期为 1 0 2a ,95 %的凋落物分解所需时间为 4 4a;7a和 2 0a林分每年通过凋落物分解释放进入林地土壤的养分总量分别为 1 2 5 1 2和 1 3 6 82kg·hm- 2 a- 1 。     

橡胶人工林生态系统氮素循环模型

根据海南儋州地区不同树龄PR107无性系橡胶人工林生态系统养分循环规律,应用系统动力学原理,构建了土壤、胶树和凋落物层3个分室之间的养分循环分室模型及其微分方程组,并测定了各分室中氮素(N)现存量、流通量和流通率。结果表明:1)土壤、胶树、凋落物层中氮素现存量的平均值分别为3069.61kg/(hm2.a),580.22 kg/(hm2.a),62.94 kg/(hm2.a),随着树龄的增加(4~24a),土壤中氮素现存量变化为先减少后增加,胶树、凋落物中氮素贮存量则呈逐年增加的趋势;2)土壤、胶树、凋落物分室之间氮素流通量变化规律为吸收量、归还量、分解量都随树龄增加而逐渐增大,而胶乳中氮素流失量在24a有所下降;3)氮素在土壤、胶树与凋落物层各分室之间的流通率大小各不相同,4~24a胶树的吸收系数为0.0640~0.1588,并随树龄增加呈指数递增的趋势,归还系数、分解系数、流失系数的平均值分别为0.1335,0.6621,0.0279。此外,本文所建分室模型可以实现对橡胶林生态系统养分动态的精确模拟和预测,并可望用于指导人工施肥。     

西双版纳自然保护区热带季节雨林破坏后的恢复状况调查

由于热带季节雨林是种植砂仁最适合的场所,因此当地居民大量地将砂仁种植在季节雨林下,对其群落结构及组成造成了严重破坏,导致大量物种的流失。对遭受破坏的群落恢复状况进行调查,结果显示,由于人为活动增加了林下的透光度和生长空间,对幼树和幼苗的生长具有一定的促进作用。只要停止人为破坏活动,经过一定时间,群落仍可得到恢复。     

砂仁种植对西双版纳自然保护区植物物种多样性的影响

砂仁在西双版纳自然保护区广泛种植,给保护区生物多样性带来了一定的危害.通过在原始林和砂仁种植地的热带季节雨林植物群落下设置样地进行调查,掌握了因种植砂仁给季节雨林所造成的物种损失情况以及对群落所带来的负面影响.结合保护区管理工作的实际,提出了解决保护区与当地群众存在的保护与发展之间矛盾的相应管理办法.     

西双版纳阳春砂仁生产中面临的问题及对策

根据西双版纳阳春砂仁生产中品种退化、低产和与热带雨林生物多样化保护的矛盾等问题,提出了在最适宜区种植砂仁,进行规范化种植、集约化管理,统一加工、打造品牌,提高单产、减少种植面积的对策。     

Dynamics of organic matter and nutrient return from litterfall in stands of ten tropical tree plantation species

We studied the rates and patterns of carbon and nutrient fluxes in litterfall in ten tropical tree plantation species grown at the USDA Forest Service Arboretum in the Luquillo Experimental Forest, Puerto Rico. The stands were 26-years old and grew under similar climatic and edaphic conditions. Individual plantation species ranked differently in terms of their capacity to return mass and specific nutrients to the forest floor, and with respect to their efficiency of nutrient use. The species that returned the most mass did not return the most P, N, or cations. Moreover, species differed according to the amount of N and P resorption before leaf fall. These differences reflect the variation in the ecophysiological response of each species to edaphic and climatic conditions. The difference between average and minimum resorption values of the species studied indicate that other environmental factors, such as heavy winds or the physical effects of heavy rains, can force the shedding of non-senesced leaves. This higher quality material, although not very much in quantity, can provide a small pulse of available nutrients to the forest floor community. The same holds true for other high nutrient/low mass fractions of litterfall such as reproductive parts and miscellaneous materials.In areas with no prevalent or strongly seasonal water limitations, temporal variations of leaf litter on the forest floor are the combined result of the rate of fall and decomposition of the falling material, and the diverse responses of species to different environmental cues. Leaf fall was inversely correlated to reduced water availability in three of the species studied. Leaf fall of the other species was correlated either to daylight duration or minimum temperatures. The results highlight the importance of understanding species performance relative to nutrient and mass metabolism before selection for plantation use, or for rehabilitation of degraded lands.     

落叶松人工林枯落物特征研究

本文研究了落叶松人工林枯落物的酸度变化、浸提液的离子含量、腐殖质组成以及微生物含量的变化，并与混交林的枯落物特征进行了比较，探讨了枯落物的矿质养分及水溶性物质的含量，为进一步研究落叶松人工林地力问题提供了借鉴。     

Litterfall, litter decomposition and nutrient dynamics in a subtropical natural oak forest and managed plantation in northeastern India

In northeastern India, subtropical forests are over-exploited for timber, fuel wood and common agricultural practice like shifting cultivation, which are responsible for the degradation of natural forest. In degraded areas, large-scale plantations of different species of Quercus have been raised since 1980 for the production of economic Tasar silk. Conversion of natural forest into plantation affects the process of nutrient cycling due to management practices. Thus, it would be of importance to study the litterfall, litter decomposition process and the factors regulating the rate of litter decay in these ecosystems to improve recommendations for their management and conservation. We recorded litterfall by using litter traps and decomposition of leaf litter by nylon net bag technique to understand the amount of organic matter and nutrient return and their release in soils of forest and plantation in Manipur, northeast India. Total litterfall was 419.9 g m⁻² year⁻¹ in plantation and 547.7 g m⁻² year⁻¹ in forest. Litter decomposition rate was faster at plantation site than the forest in the early stage of litter decomposition whereas the reverse was observed at later stages of decomposition. Stepwise regression analysis showed the significant role of relative humidity and mean temperature on mass loss rates in the forest. Relative humidity, maximum temperature, population of fungi and actinomycetes were the best predictor variables for mass loss rates in plantation. Nutrient retranslocation efficiency and the immobilization of N and P in forest litter were higher than plantation. This suggests that Q. serrata growing in natural ecosystem in oligotrophic condition adapted strong nutrient conservation mechanisms to compete with the other plant species for the meager soil nutrients. The same species in plantation loses these adaptive capabilities because of exogenous supply of nutrients and in the absence of intense competition with other plant species. Thus, the optimization of organic and chemical fertilizer input in plantation is recommended for maintaining the soil fertility level to produce quality leaf for silkworm by conserving essential nutrients in the system.     

嘉陵江上游低山暴雨区3种林分凋落物量及其N、P归还

通过对广元低山暴雨区湿地松（Pinus eliottii Engelm）纯林、刺槐（Robinia pseudoacacia）纯林、湿地松与刺槐混交林（mixed stands of Pinus eliottii and Robinia pseudoacacia）3种人工林凋落物量与养分归还的研究表明,3种林分的年凋落量范围在3609．6kg·hm^-2·a^-1到4917．6kg·hm^-2·a^-1,除刺槐林外,湿地松林和混交林均以叶的凋落量占优势,分刺占各自总凋落量的87．45％、55％。湿地松纯林凋落量1a中出现3次峰值（5月、7月、11月或12月）。刺槐纯林出现两次峰值（7月、11月或12月）,混交林与刺槐纯林相似。3种林分N、P的年归还量均以刺槐林最大,湿地松纯林最小,这与凋落物总量的大小排序相反。通过凋落物各组分的养分归还中,落叶的归还量占主体。3种林分相比,湿地松林和混交林的凋落总量明显高于刺槐林,但养分归还量却有所不同,刺槐林和混交林明显高于湿地松林,这说明阔叶林有良好维持地力的能力,针阔混交比针叶纯林更能改善土壤肥力。     

Litter production and decomposition dynamics in moist deciduous forests of the Western Ghats in Peninsular India

A field study was conducted in the moist deciduous forests of the Western Ghats (India) to test the following three hypotheses: (1) Litter production in tropical forests is a function of the floristic composition, density, basal area and disturbance intensity; (2) Decay rate constants of tropical species is an inverse function of the initial lignin/nitrogen ratio; (3) Decomposition rates in tropical forests are faster than temperate forests.

Litter fall was estimated by installing 63 litter traps in the moist deciduous forests of Thrissur Forest Division in the Western Ghats at three sites. Litter fall followed a monomodal distribution pattern with a distinct peak during the dry period from November–December to March–April.Dillenia pentagyna, Grewia tiliaefolia, Macrosolen spp.,Xylia xylocarpa, Terminalia spp.,Lagerstroemia lanceolata, Cleistanthus collinus, Bridelia retusa, andHelicteres isora were the principal litter producing species at these sites. The annual litter fall ranged from 12.18 to 14.43 t ha⁻¹. Structural attributes of vegetation such as floristic composition, basal area, density and disturbance intensity did not directly influence litter fall rates.

Leaf litter decay rates for six dominant tree species were assessed following the standard litter bag technique. One hundred and eight litter bags per species containing 20 g samples were installed in the forest floor litter layer at the same three sites selected for the litter fall quantification exercise. The residual litter mass decreased linearly with time for all species. In general, less disturbed sites and species adapted to higher nitrogen availabilities exhibited relatively higher decay rate coefficients (k). The rapid organic matter turnover observed in comparison with published temperate forest litter decay rates confirms that tropical moist deciduous forest species are characterised by faster decomposition rates.

Mean concentrations of N, P and K in the litter were profoundly variable amongst the dominant species. Initial nitrogen content of the leaf litter varied from 0.65 to 1.6%, phosphorus from 0.034 to 0.077% and potassium from 0.25 to 0.62%.C. collinus, an understorey shrub consistently recorded the lowest litter concentrations for all nutrients. The overriding pattern is one of higher nutrient levels in the overstorey leaf litter and lower concentrations in the understorey litter. Furthermore, as decomposition proceeded, the nitrogen concentration of the residual biomass increased.     

孟加拉吉大港地区丘陵森林有机物积累

在孟加拉吉大港丘陵地区,调查了热带季风气候条件下的3种人工林(7年生大叶相思(Acacia auriculiformis)林、15年生大叶相思林和18年生混交林)和1种天然林的森林凋落物及其对土壤性质的作用.结果表明,总的有机质积累随人工林树龄增加而增加,但是年积累量随之降低.在同一植被类型内,不同坡位新鲜或部分分解的凋落物有机质累计量变化较大,坡底部有机质积累量最高,沿着山坡向上逐渐减少.在15年生大叶相思人工林内,土壤整合有机物积累量变化趋势与新鲜或部分分解有机质积累量变化趋势相反.在7年生和15年生的大叶相思林以及18年龄的阔叶混交人工林内,新鲜、部分分解和完全分解(含土壤整合有机质)有机质总生产速率分别是2554.31、705.79和1028.01kg.ha-1·a-1,新鲜凋落物有机质在3种林分中的生产速率分别是38.23,19.40和30.48 kg·ha-1·a-1.3种人工林和自然林内,平均新鲜凋落物的有机质积累占有机质产出总量的32.45%,部分分解凋落物占13.50%,而全分解整合土壤有机质占54.56%.森林土壤酸度随凋落物分解阶段的深入而增加.