Effects of Meat and Phosphate Level on Water-Holding Capacity and Texture of Emulsion-Type Sausage During Storage

This paper was designed to verify the influence of phosphate on water-holding capacity （WHC） and texture of emulsiontype sausage prepared with pre-rigor meat, ageing meat or frozen meat. Pre-rigor pork, ageing pork and frozen pork were pre-blended with five levels of phosphate and made into emulsion-type sausage. The yield, hardness and total expressible fluid （TEF） were measured with texture profile analysis machine and pressiometer when emulsion-type sausage was produced. Meanwhile, hardness and purge loss （PL） were measured during 30 d storage. As emusion-type sausage made by pre-rigor meat, higher yield and relatively stable hardness could be found. It indicated that increasing of phosphate level caused an alleviatable effects in increasing of hardness when emulsion-type sausage made by pre-rigor meat, but opposite effects made by ageing meat or frozen meat. The distribution of PL of emulsion-type sausage was found to be affected by phosphate addition. Significant decrease of PL could not be obtained by increasing of phosphate level during storage. Pre-rigor meat improved WHC and texture of emulsion-type sausage. Problem of WHC and texture of emulsiontype sausage during storage could not be resolved by single use of phosphate at relatively higher level （3%） of NaCl.

Study on Water Conservation Capacity of Litter from Different Types of Forest in Caohai Basin

[Objective]The research aimed to understand water conservation capacity of litter from different forest types in Caohai basin. [Method] Current storage amount,water holding capacity and precipitation interception ability of litter from 4 types of forest were investigated and studied. [Result]The order of exist litter amount was grass slope ＆gt;shrub forest ＆gt;mixed broad leaf-conifer forest ＆gt;coniferous forest. The order of natural water holding capacity was mixed broad leafconifer forest ＆gt; coniferous forest ＆gt; grass slope ＆gt; shrub forest. The relevance between water holding capacity of litter and soaking time was in line with this formula： y = kln（ x） ＋ b. During 0-120 min of litter soaking,water holding capacity increased rapidly. After 120 min,the increasing trend remained flat until closing to the maximum water holding capacity. The relevance between water absorption rate of litter and soaking time was in line with this formula： y = a ＋ bx-1. In the beginning of soaking,water absorption rates of litter from different woodlands showed great difference. As soaking time went by,water absorption rates of litter from different woodlands all declined sharply. During 0-120 min,declining velocity of water absorption rate was quicker. After 120 min,the declining trend tended to be slow. The maximum water holding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. The maximum precipitation interception amount of litter presented the order of shrub forest ＆gt; grass slope ＆gt; mixed broad leafconifer forest ＆gt; coniferous forest. Effective impounding capacity of litter presented the order of shrub forest ＆gt; mixed broad leafconifer forest ＆gt; grass slope ＆gt; coniferous forest. [Conclusion]The research could provide support for the construction of water conservation forest in Caohai basin.

The Scavenging of Free Radical and Oxygen Species Activities and Hydration Capacity of Collagen Hydrolysates from Walleye Pollock(Theragra chalcogramma) Skin

Fish skin collagen hydrolysates （FSCH） were prepared from walleye pollock （Theragra chalcogramrna） using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of 〈1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical （DPPH）, superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione （GSH）. FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore FSCH may have potential applications in the medicine and food industries.

Study on Quantitative Model of Karst Drainage Basin Water-Holding Based on Principal Component Analysis: A Case Study of Guizhou, China

In Karst drainage basins, there are the ground water and underground water exchanging frequently, and the shortage of water resources due to having the special double aquifer mediums and unique surface and subsurface river systematic structure. This paper is to select 20 research sampling areas coming fromGuizhouProvince, and according to the spectral characteristics of the catchment water-holding mediums and vegetations, and using the remote sensing technique, extract the watershed vegetation index. According to the principle of principal component analysis, using the software of Spss and Matlab is to analyze the impacts of watershed vegetation type on the catchment water-holding ability, and establish the principal component analysis function. Studies have shown that: 1) the watershed vegetation coverage rate plays an important role in Karst basin water-holding ability;2) the catchment water-holding ability is the comprehensive reflection and manifestation of the Catchment Water-storing Capacity (CWC);3) it is much better effects and higher accuracy to monitor/forecast the catchment water-holding volume by using the vegetation indices.

Grass Litter Decomposition Rate and Water-Holding Capacity in Dry-Hot Valley of Jinshajiang River

The decomposition rate and the water-holding capacity of 6 kinds of grass litters were studied in the Jinshajiang river dry-hot valley. The results showed that the dry weight remains reduced with time but did not have a direct correlation with time. The decomposition litters were affected by climate, character of litter, animalcule and soil animal. The climate factors of temperature and humidity were important especially. The water-holding capacity was in the sequence ofN. wightii （336%）, P. notatum Flugge （248%）, H. contortus （L.） Beauv （209%）, B. pertusa （L.） A. Camus（206%）, L endecaphylla Jacq （174%）, D. annulatum （Forsk.） Stapf （168%）. After 24 months decomposition the remaining dry weight of the litter was in the sequence as follows： 15.12% for N. wightii, 26.38% for I. endecaphylla Jacq, 27.23% for B. pertusa （L.） A. Camus, 30.78% for P. notatum Flugge, 39.72% for H. contortus （L.） Beauv and 39.76% for D. annulatum （Forsk.） Stapf. The decomposition rate and water-holding capacity ofN. wightii are at the highest level. It is important for the development, improvement and conservation of the grassland soil.

Aspects of forest restoration and hydrology:the hydrological function of litter

Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This study relates litter levels to water holding capacity and effective water retention among forest fragments under different passive restoration stages:46,11,and 8 years to better understand litter hydrological functions in the Cerrado.Water retention capacity and effective water retention capacity of litters(unstructured materials,branches and leaves)in the field were monitored on a monthly basis.Total litter accumulation at 46 years was significantly higher than that of the other succession stages.Unstructured litter mass was significantly higher than that of leaves and branches.The 46-year stage had the highest water holding capacity in the leaf fraction,followed by unstructured material and branches.Although the water holding capacity was lower in the oldest resto-ration,this site showed the highest efficiency under field conditions.The process was quickly reestablished,as the 11-year restoration showed results closer to that for the 46-year stage in comparison to the area at 8 years.Thus,passive restoration plays a key role in soil water mainte-nance due to the influence of litter in Cerrado savannas.Deforestation and the imminent need of restoring degraded sites,highlight the need for further studies focused on bet-ter understanding of the process of forest restoration and its temporal effect on soil water recovery dynamics.

Effect of weak magnetic field on the water-holding properties,texture,and volatile compounds of pork and beef during frozen storage

The weak magnetic field has recently attracted much attention for improving the quality of frozen food due to its mild effectiveness and near-complete transmission through the food matrix.This study aimed to explore the effect of the magnetic field with 1 mT and 50 Hz on the freezing process and storage quality of pork and beef.The results showed that the freezing point of beef stored under the magnetic field was-1.7℃,which was 0.5℃ lower than that of conventional frozen(CF)groups,and the phase transition times of pork and beef were reduced by 55.56%and 50.00%,respectively.The magnetic field maintained higher water-holding capacity and decreased drip loss and cooking loss for both types of meat.Coherently,the evaporation and redistribution of water was inhibited by MF,as indicated by the magnetic resonance imaging results.The magnetic field also effectively moderated the hardening in texture,odor deterioration and color change of frozen pork and beef.Less accumulation of free amino acids suggested the degradation of protein was suppressed under magnetic field.The present study would provide a scientific reference for the application of weak magnetic field in meat preservation.

Low-temperature combined with high-humidity thawing improves the water-holding capacity and biochemical properties of Portunus trituberculatus protein

This study compared the effects of conventional thawing methods(water immersion thawing(WIT,(25±1)℃),natural air thawing(AT,(25±1)℃,relative humidity(RH(65±2)per cent),refrigerator thawing(RT,4℃,RH(80±2)per cent)and low-temperature(LT)combined with high-humidity thawing LT,-1℃to 1℃(LT-1-1),2-4℃(LT2-4),5-7℃(LT5-7)and 8-10℃(LT8-10),RH>95 per cent)on the water-holding capacity,lipid oxidation and biochemical properties of Portunus trituberculatus(P.trituberculatus)myofibrillar protein.The results showed that WIT and AT significantly decreased the water-holding capacity while dramatically increasing lipid oxidation,protein oxidation and degeneration,resulting in serious P.trituberculatus quality deterioration.High humidity was beneficial for P.trituberculatus\.ha\A/\ng.The thawing time of P.trituberculatus under the conditions of LT2-4 was only 39.39 per cent of that of conventional air thawing at 4℃(RT),and the LT2-4 samples not only maintained better water-holding capacity but also had an obviously reduced degree of lipid oxidation,protein oxidation and denaturation.Thawed samples LT2-4 and LT5-7 provided better maintenance of P.trituberculatus quality than the LT-1-1 and LT8-10 samples.The best quality was exhibited after thawing at 2-4℃.The levels of thiobarbituric acid reacting substances,carbonyl content and surface hydrophobicity observably decreased in these samples,while the total sulfhydryl contents dramatically increased compared to those of conventionally thawed samples,indicating lower lipid oxidation and protein oxidation.Moreover,the Ca2+-ATPase activity of the sample thawed at 2-4℃(2.06 μmol Pi/mg prot/h)was markedly higher than that of samples subjected to WIT and AT.The product qualities observed after thawing at-1℃to 1℃,5-7℃and 8-10℃under LT were comparable to that observed by RT.Considering its thawing efficiency and product quality,LT is a suitable method for the thawing of P.trituberculatus,and the ideal thawing conditions were LT at 2-4℃.

地被物调控对川西亚高山次生林枯落物持水性能的影响

为弄清地被物调控对次生林地水源涵养能力的影响,对阿坝州米亚罗林区3个退化程度(轻度、中度、重度)的岷江冷杉次生林分别进行了7个地被物调控处理,其中移出3个梯度(10%-C1、30%-C2、50%-C3)、输入3个梯度(10%-R1、30%-R2、50%-R3)、对照-CK,监测其枯落物持水性能的变化,结果显示:次生林的枯落物蓄积量受林分密度和林分结构以及分解速率影响,表现为中度退化>重度退化>轻度退化,枯落物最大持水量与蓄积量呈正相关,也表现为中度退化>重度退化>轻度退化,且中度退化次生林枯落物最大持水量比重度退化次生林高出50.45%,比轻度退化次生林高出57.42%。地被物调控后不同次生林蓄积量、最大持水量和有效拦蓄量均是R2处理(移入30%)最高,其中轻度退化次生林R2的最大持水量比CK(对照)高出35.48%;中度退化次生林R2的最大持水量比CK高出312.24%;重度退化次生林R2的最大持水量比CK高出47.93%。不同次生林最大持水率与最大持水量、蓄积量没有相关性,其中中度退化次生林R3的最大持水率(移入30%)最高,比CK高71.66%。从监测数据来看,R2处理能较快地对提升枯落物持水性能作出响应,且在中度退化次生林的效果最好。

亚热带树种在未成林造林地的凋落物量和周转与叶片性状的关系

【目的】测定亚热带树种的叶片功能性状、凋落叶质量、凋落物量和周转期,揭示叶片性状对凋落物量和周转的影响,为杉木采伐后如何选择造林树种以改善土壤肥力提供科学依据。【方法】选取在二代杉木林采伐迹地营造的17种亚热带树种,测定其在3年生未成林造林地的凋落物量和周转期,同时测定各树种的叶片功能性状(比叶面积、干物质含量、氮含量等)和凋落叶质量(碳氮比、单宁含量、可溶性糖含量等),建立叶片性状与凋落物量和周转期的回归关系。【结果】17种树种中,米老排凋落物量最高(6.67 t·hm^(-2)a^(-1)),杉木凋落物量最低(0 t·hm^(-2)a^(-1));江南桤木凋落叶周转期最短(0.09年);深山含笑凋落叶周转期最长(1.09年)。凋落物量随比叶面积增加而增加,随叶氮含量增加而降低;凋落叶周转期随凋落叶碳氮比和单宁含量增加而增加,随凋落叶最大持水率增加而降低。【结论】在亚热带未成林造林地中,凋落物量受比叶面积和叶氮含量的影响,凋落叶周转期受凋落叶碳氮比、单宁含量和最大持水率的影响;杉木在未成林造林地阶段的凋落物归还量极少。经营亚热带人工林时,要考虑种植比叶面积和凋落叶最大持水能力较高、凋落叶单宁含量和碳氮比较低的树种,以提高林地凋落物归还量和周转速率,改善退化人工林的土壤肥力。

海南热带雨林不同林分凋落物储量及其持水特性

以海南热带雨林地区3种典型林分——橡胶林、原始林和次生林为研究对象,通过测定其凋落物储量、持水量、持水率及凋落物吸水速率,探究热带雨林不同林分凋落物储量及持水特性。结果表明:1)原始林的凋落物储量(2.791 t/hm^(2))最大,显著高于次生林(2.077 t/hm^(2))和橡胶林(1.660 t/hm^(2),P<0.05)。2)对于凋落物持水量和持水率,原始林和次生林均随着浸水时间的变化而增大,原始林的凋落物持水量和持水率高于次生林,随后趋于相对平稳,而橡胶林凋落物持水量和持水率随着浸水时间无明显趋势。整体而言,各林分凋落物吸水速率与浸水时间之间的关系呈较好的幂函数关系。3种林型最大持水量表现为:原始林(8.041 t/hm^(2))>次生林(6.251 t/hm^(2))>橡胶林(4.896 t/hm^(2));3)对于吸水速率和失水速率而言,失水率表现为:橡胶林>次生林>原始林;最大失水量表现为原始林(5.225 t/hm^(2))>次生林(4.626 t/hm^(2))>橡胶林(4.079 t/hm^(2)),而最大失水率表现为:橡胶林(246.319%)>次生林(222.649%)>原始林(189.748%);4)因原始林凋落物储量最大,其最大拦蓄量和有效拦蓄量均表现为原始林>次生林>橡胶林;最大拦蓄率和有效拦蓄率均表现为原始林≈橡胶林>次生林。综上,不同林分凋落物储量和持水性存在显著差异,原始林凋落物相比于其他2种林分具有较高凋落物储量和凋落物持水量以及较低的失去率,表明热带原始林凋落物的累积对于调节森林水量和减弱地表径流的发生具有重要作用。

川西亚高山森林苔藓与枯落物持水特征

森林苔藓和枯落物在水土保持、水分涵养方面具备重要作用,但现有研究多单一关注苔藓或枯落物,对苔藓-枯落物层的整体效应的认识较少,尤其针对高海拔西南森林林下的苔藓-枯落物层,更为鲜见。本文以川西贡嘎山针叶林和阔叶林地被层(苔藓、枯落物)为研究对象,通过野外调查、采样瓶取样浸水试验,分析了单一苔藓、单一枯落物及苔藓-枯落物整体的持水特征。结果表明:(1)贡嘎山苔藓和枯落物最大持水率为327.9%~432.6%,最大持水量为16.6~79.4 t/hm^(2),有效拦蓄量为7.1~34.2 t/hm^(2)。针叶林比阔叶林具有更大的持水能力和水分拦蓄能力。(2)不同地被组分中,苔藓-枯落物层持水率、有效拦蓄率、持水量和拦蓄量最大,苔藓显著提高了针叶林地被层的水源涵养能力;(3)地被层持水量与时间呈对数关系,吸水速率与时间呈幂函数关系,不同组分持水量和持水率均在0~2 h内迅速增长,2~12 h内缓慢增长,12 h时几乎达到饱和状态。(4)与单一苔藓或枯落物层相比,苔藓-枯落物整体的吸水速率更快,具有更高效的短期降水拦蓄能力。本研究结果可为亚高山森林水源涵养和生态水文研究与保护提供参考和理论基础。

间伐对杉木林枯落物和土壤水源涵养能力的动态变化分析

探讨不同间伐年限对杉木林枯落物层和土壤层持水能力的影响,为评估杉木林水源涵养功能对间伐的响应提供科学依据。以浙西南景宁县间伐1年、间伐3年、间伐8年和未间伐的杉木林为对象,采集枯落物与土壤样品,分析测定枯落物含水率、持水能力、土壤容重、非毛孔隙度并计算相关指标。结果表明:杉木林枯落物现存量在不同间伐年限间的差异并不显著(P>0.05);枯落物持水量、持水速率与浸水时间的关系分别符合对数函数和幂函数;间伐8年的杉木林枯落物层的最大持水率、最大拦蓄率和有效拦蓄率均显著高于未间伐林分(P<0.05);间伐3年、间伐8年的杉木林枯落物最大持水量和有效拦蓄量均显著高于未间伐林分;间伐8年杉木林地0~10 cm土层土壤容重显著降低(P<0.05),非毛管孔隙度显著增大,非毛管持水量显著增加了22.4%(P<0.05),而对10~30 cm土层土壤储水性能相关指标的影响不显著(P>0.05)。综上,杉木林枯落物层和土壤层的水源涵养功能随着间伐年限的延长而增强。

9个树种鲜叶凋落物和枯叶凋落物的酸缓冲能力

【目的】探讨9个树种凋落物之间及同一树种鲜叶凋落物和枯叶凋落物之间的酸缓冲能力差异及其影响因素,为酸雨背景下人工造林树种选择及可持续经营提供依据。【方法】在模拟酸雨条件下,测定9个南方常见树种的鲜叶凋落物和枯叶凋落物的酸缓冲能力、pH值、比叶面积、平均吸水速率和淋洗液盐基离子含量等指标,分析不同树种凋落物酸缓冲能力及同一树种鲜叶凋落物与枯叶凋落物酸缓冲能力的差异及其影响因素。【结果】(1)不同树种鲜叶凋落物和枯叶凋落物的酸缓冲能力均存在显著差异,粉单竹、香樟及无患子鲜叶凋落物和枯叶凋落物的酸缓冲能力均较强。(2)不同树种鲜叶凋落物和枯叶凋落物酸缓冲能力的影响因素不同,鲜叶凋落物酸缓冲能力的影响因素为凋落物pH值和比叶面积,枯叶凋落物酸缓冲能力的影响因素为凋落物pH值、比叶面积、平均吸水速率和淋洗液K+、Mg2+含量。(3)鲜叶凋落物和枯叶凋落物酸缓冲能力的差异与树种有关;杉木、马尾松和木莲鲜叶凋落物的酸缓冲能力显著高于枯叶凋落物,而粉单竹、香樟、垂枝红千层和无患子鲜叶凋落物的酸缓冲能力显著低于枯叶凋落物;鲜叶凋落物与枯叶凋落物酸缓冲能力的影响因素也与树种有关。【结论】9个树种的鲜叶凋落物和枯叶凋落物都能对酸雨起到缓冲作用;不同树种凋落物的酸缓冲能力存在显著差异;同一树种鲜叶凋落物和枯叶凋落物的酸缓冲能力也存在差异;粉单竹、香樟、无患子等树种的鲜叶凋落物和枯叶凋落物酸缓冲能力均较强。

4种园林绿化植物凋落物混合对其持水特性的影响

适当保留凋落物层有助于改善城市绿地的水文效应,但不同树种凋落物混合对凋落物层的持水特性有何影响尚不清楚。以丁香、垂柳、日本晚樱和五角枫的凋落叶以及上述凋落叶5种形式的混合物为对象,基于室内浸泡试验检测混合形式及其比例对凋落物持水特征参数(含吸水和失水过程)的非加和性影响。结果表明,1)丁香-晚樱凋落叶以7∶3和5∶5(质量比,后同)混合使其最大持水量较预期显著降低,以3∶7混合则使其持水在叶片间隙中的分配比例显著提高;五角枫-垂柳凋落叶混合使其最大持水量(5∶5和4∶6)、间隙分配比例(4∶6)和最大吸水速率(5∶5和3∶7)均较预期显著降低;五角枫-晚樱凋落叶以3∶7混合使其间隙分配比例较预期显著降低;丁香-五角枫凋落叶以4∶6混合使其吸水速率较预期显著提高;而丁香-垂柳凋落叶以7∶3、4∶6或3∶7混合分别使其间隙分配比例和最大吸水速率较预期显著提高(P<0.05)。2)丁香-晚樱凋落叶以7∶3和5∶5、五角枫-垂柳凋落叶以6∶4、3∶7、五角枫-晚樱凋落叶以7∶3、4∶6以及丁香-五角枫凋落叶以4∶6、3∶7混合均使其最大失水率较预期显著降低,而丁香-垂柳凋落叶以除6∶4外的质量比混合则产生相反作用;丁香-晚樱以6∶4和3∶7、丁香-五角枫和丁香-垂柳凋落叶以任一质量比混合均使其最大失水速率较预测显著提高(P<0.05)。

琼西北3种林分类型枯落物与土壤的持水能力

为探讨琼西北典型水土流失区蚂蝗岭流域不同林分类型枯落物和土壤水文效应,采用浸泡法、环刀法对桉树人工林、橡胶树人工林、马占相思人工林3种不同林分类型枯落物和土壤水文功能进行定量分析,采用熵权法(EWM)综合评价水源涵养能力。结果表明:3种林分类型枯落物储量为3.01~14.66 t·hm^(-2),表现出马占相思人工林>橡胶树人工林>桉树人工林,均以半分解层为主,占比为75.09%~81.86%;最大持水量为8.60~33.95 t·hm^(-2),有效拦蓄量为6.92~26.73 t·hm^(-2),均为马占相思人工林>桉树人工林>橡胶树人工林。枯落物持水量与浸泡时间呈对数函数关系(R^(2)>0.940);枯落物吸水速率与浸泡时间呈幂函数关系(R^(2)>0.880)。3种林分类型土壤容重为1.45~1.52 g·cm^(-3),总孔隙度为32.82%~37.56%,有效持水量为61.80~77.16 t·hm^(-2),土壤持水能力排序为马占相思人工林>桉树人工林>橡胶树人工林。土壤初渗速率为24.74~29.67 mm·min^(-1),其中,马占相思人工林最高;土壤稳渗速率为1.01~1.38 mm·min^(-1),土壤入渗速率与入渗时间呈幂函数关系(R^(2)>0.920)。3种林分类型水源涵养能力综合排序为马占相思人工林(81.0987)>桉树人工林(69.7416)>橡胶树人工林(67.1514),土壤入渗性能和枯落物储量是影响该区域水源涵养能力的主导因素。综合3种林分类型枯落物及土壤持水能力,马占相思人工林的水源涵养能力较强,建议在对桉树人工林及橡胶树人工林更新时可种植马占相思,以提高其保持水土、涵养水源的功能。

Hydraulic characteristics and vegetation performance of the Yellow River sediment modified by biochar

The Yellow River sediment(YRS)is an important potential soil resource for the mine land reclamation and ecological restoration in the arid regions of northern China.However,it has the shortcomings of poor water-holding capacity and needs to be modified urgently.Therefore,two types of biochar,namely rice husk biochar(RHB)and coconut shell biochar(CSB),were utilized in this study to modify the YRS and compared with rice husk ash(RHA).Some engineering properties of the modified YRS(MYRS),including pore structure,water retention,permeability,and vegetation performance,were investigated by considering the effects of biochar types and dosages.Results showed that the addition of the three materials decreased the bulk density of the YRS and increased the volume of extremely micro pore(d<0.3µm),as well as the effective porosity and capillary porosity,thus contributed to an increase in the water-holding capacity of the sediment.Among the three conditioners,RHB is optimal choice for improving the water-holding capacity of YRS.Furthermore,the effect becomes more pronounced with increasing application rates.With the addition of the three materials,the permeability coefficients of MYRS gradually decreased,while the water retention rate during evaporation significantly increased.The pot experiment showed that the three conditioners all had significant promoting effect on the growth of oats.In particular,compared to plain soil,the total biomass of oats grown for 21 days increased by 17.46%,32.14%,and 49.60%after adding 2%,4%,and 8%RHB,respectively.This study introduces a new approach for using YRS as planting soil in arid and semi-arid areas of China to facilitate mine ecological restoration.

Study on Litter Water Interception Capacity of Phyllostachys edulis Plantations with Different Densities

The litter amount and the water holding characteristic parameters,such as the maximum water holding capacity and rate,the water absorption rate and the modified interception amount of Phyllostachys edulis plantations with four densities were studied in Huangshan district.The results are as follows:The total amount,thickness and natural water content of litters under all the four stands tested were different.The total litter amount in different stands ranged between 3.98 t·ha-1 to 6.00 t·ha-1, which in the stand with the density of 3 000 stems·ha-1 was the most.The ratio of maximum water-holding capacity of litter in various stands ranged from 317.09%to 347.58%.The maximum water holding capacity of litter in the stand with the density of 3 000 stems·ha-1 was 20.70 t·ha-1. By analyzing,the relationship between the water holding capacity of litter and the immersion time followed the equation of:S = alnt + b（a is the coefficient;b is the constant term）.The relationship between the water absorption speed of the litter and the immerse time followed the equation of: V = ctd（c is the coefficient;d is the exponential term）.The litter water capacity increased rapidly within the first four hours,and then increased slowly.The results also showed that the hydrological character of litter was positively related to density in Ph.Edulis forest.Therefore, it is important to choose appropriate density for enhancing the eco-hydrological benefits of litter layer in Ph.edulis forest.

华南典型人工林凋落物的持水特性

对于华南地区的杉木(Cunninghamialanceolata)林、马尾松(Pinusmassoniana)林、湿地松(Pinuselliottii)林、马占相思(Acaciamangium)林和尾叶桉(Eucalyptusurophylla)林的凋落物的储量、持水量、持水率和吸水速率进行了研究。结果表明,杉木林的凋落物的干重(6 .5×10 3 kg·hm-2 )最大,其次是马尾松林和马占相思林(5 .5×10 3 kg·hm-2 ) ,而湿地松林(4.1×10 3 kg·hm-2 )和尾叶桉林较小(4.0×10 3 kg·hm-2 )。凋落物持水量呈现杉木林>马占相思林>尾叶桉林>马尾松林>湿地松林。各林分凋落物的最大持水量为杉木林17.9×10 3 kg·hm-2 ,马占相思林14 .8×10 3 kg·hm-2 ,尾叶桉林14 .0×10 3 kg·hm-2 ,马尾松林10 .6×10 3 kg·hm-2 ,湿地松林9.8×10 3 kg·hm-2 。尾叶桉林、杉木林、马占相思林、湿地松林和马尾松林的凋落物最大持水率分别为35 1%、2 74 %、2 6 9%、2 35 %和191%。凋落物持水量和凋落物持水率随着浸泡时间的增加按照对数方程增加。5种林分中尾叶桉林的凋落物吸水速率在各浸泡时间后居首位,杉木林和马占相思林中等,湿地松林较小,而马尾松林最小,各林分的凋落物的吸水速率随浸泡时间的增长按方程Y =a +b·t-1下降。

三峡库区3种林下枯落物储量及其持水特性

通过对三峡库区3种森林类型(松栎混交林、栓皮栎纯林、马尾松纯林)林下枯落物储量调查分析及其持水特性试验,得到不同森林类型林下枯落物储量、最大持水量、吸水速率等水文特征参数。结果表明,栓皮栎纯林林下枯落物储量最大(10.7t/hm2),其后依次为松栎混交林(10.1t/hm2)、马尾松纯林(5.8t/hm2)。松栎混交林林下枯落物未分解层最大持水量为其风干重的310.4%,栓皮栎纯林为286.5%,马尾松纯林为221.1%。松栎混交林林下枯落物半分解层最大持水量为其风干重的252.7%,栓皮栎纯林为249.2%,马尾松纯林为201.5%。经分析拟合,得到林下枯落物未分解层和半分解层吸水速率与浸泡时间之间关系式为S=ktn。研究结果还表明,在同为中龄林条件下,三峡库区针阔混交林林下枯落物持水能力大于阔叶树纯林或针叶树纯林林下枯落物持水能力。