【作者】 丁军；

【导师】 王兆骞；

【作者基本信息】 浙江大学 ， 生态学， 2003， 博士

【摘要】 南方红壤丘陵区属于十分严重水土流失区，在该地区开展人工水土保持林建设是一项十分迫切的任务。2001年4月～2002年7月期间在浙江省兰溪市水土保持站，从人工水土保持林建成及其水土保持效应、人工林冠层截留降水规律、枯枝落叶的周年变化及其水文效应、人工林根系对土壤的抗冲增强效应、人工林地土壤物理特性的空间变化特征和人工林地小气候变化特征六个方面对南方红壤丘陵区人工水土保持林的生态学特征及其水土保持机理进行了研究，研究结果如下： 1、人工水土保持林建成及其水土保持效应 (1)各试验区树木高度的增加、树胸径的扩大和林冠郁闭度的升高总的趋势是一致的，均是随生长时间的延长而相应增加。但各区由于树木类型的不同，也表现出较大的差异，毛竹林年平均增高缓慢，树胸径维持在相对稳定的水平，落叶高峰期集中在4～5月；混交林树木的增高和树胸径的扩大也比较缓慢，郁闭度的周年变化与落叶周年变化规律一致；杉木林树高增加相对较快，而胸径的扩大相对较慢，周年平均郁闭度较低；柑橘树干较低，年际间变化不明显，生长主要集中表现为树冠的扩大和郁闭度的升高。 (2)各试验区水土流失随林木的生长呈现出先迅速减少，而后缓慢减少，最后趋于稳定平衡的趋势。具体表现在水土流失的几个指标上：第一，毛竹林、混交林和杉木林植林3年后地表径流没有明显出现，常规柑橘林和密柑橘林在建成过程中对地表径流量减缓作用相对较弱，地表径流在植林6年以后将不再产生。第二，从土壤悬移质的动态变化来看，随林地建成时间的延长，悬移质产生量逐渐减少。不同试验区土壤悬移质的动态变化存在显著差异，大体上呈现出两类，一类是毛竹林、混交林和杉木林，它们悬移质的动态变化具有明显的分界点，大致以林木植上的第2年为界，第2年以前悬移质的总量占9年总量的93.7％以上，第2年以后悬移质的总量急剧减少，到第5年将没有悬移质产生。另一类是常规柑橘林和密柑橘林，它们悬移质变化的分界点为第3年，第3年以前的悬移质量为其9年总量的76.7％以上，第3年以后维持较为平缓的减少，第9年还有少量产生。第三，土壤推移质的动态变化与土壤悬移质的动态变化不同，各试验区的变化趋势相一致，第2年以后各试验区内推移质均没产生。第四，土壤的悬移质和推移质在土壤侵蚀量中所占比重的大小，决定它们对土壤侵蚀模数动态变化规律影响程度的轻重。从3年的土壤悬移质和土壤推移质的动态变化来看，在植林的第1年土壤侵蚀以推移质的形式为主，以后由以土壤推移质为主逐渐向以土壤悬移质为主过渡，到第3年以后土壤侵蚀在各试验区均以悬移质为主。 2、不同人工林冠层截留降雨规律 (1)林冠面截留具有以下几个特点，一是存在一个面饱和点，当降雨量低于面饱和点时，整个冠层面的降雨截留量逐渐增大而截留率逐渐减小，当降雨量超过面饱和点时，整个冠层的降雨截留量保持不变，而截留率迅速减小；二是林冠层面摘要一2一饱和点具有动态性，随林冠层郁闭度的增大，饱和点升高，随郁闭度减小，饱和点降低;三是降雨间隔时间越长，面截留降雨量越大，截留率越高，相反降雨间隔时间越短，面截留降雨量越小，截留率越低。 (2)林冠层纵向截留具有以下4个特点:第一，延迟林内降雨开始的时间:第二，林内降雨结束时间延长;第三，降低开始30分钟(I3。)雨强;第四，减小降雨呈乳。 (3)林冠层的横向截留表现出:在降雨量小于10mm情况下，冠层对降雨的截留量随距主干基部距离的增加截留量相对减少，各林型减少量大小的顺序依次为柑橘林、毛竹林、混交林和杉木林。降雨量大于Zomm情况下，它表现出随距主干基部距离的增加截留量相对增加，各林型截留增加量的大小顺序依次为杉木林、毛竹林、混交林和柑橘林。3、枯枝落叶的周年变化规律及其水文效应 各试验区的落叶出现两个高峰期(5月和12月)。常绿树种毛竹林的落叶高峰主要集中在5月，杉木、柑橘和混交林的落叶高峰主要集中在12月。枯落物的周年分解变化规律从整体上可以看出，柑橘林的分解率>杉木林>毛竹林>混交林。从各试验区枯落物周年储蓄量变化动态来看，毛竹林的枯落物蓄积量在5月份达到最高，而其它各试验区枯落物的累积量高峰出现在12月份。各试验区枯落物的最大持水量的变化规律与它们各自周年储蓄量相一致。毛竹林枯落物的最大持水率在各个时期均为最高，在其它试验区中则表现出随季节推移枯落物的最大持水率先逐渐增大而后又逐渐减小.但它们的转折点所处的季节各不相同，混交林和杉木林的转折点在10月份，而柑橘林的转折点在7月份。4、人工林根系对土壤的抗冲增强效应研究 (l)土壤剖面观测发现，根系密度随土层深度的增加急剧减少，各林地有效根系密度(直径簇1。。的根系)存在差别，毛竹林有65%分布在O一3Ocln土层，并且0一loc二最多，占总数33%;混交林集中在。一ZoC。土层中的根系，约占总根数的61%一72%;杉木地约有43%的根系分布于O~ZOC。土层;柑橘林根系分布以0一10。。为主，占其总量的45%。根干重的分布也具有和根系密度相同的变化规律更多还原

【Abstract】 Soil and water loss is very serious in south red soil hilly region. It is very impendent mission for this region to construct soil and water conservation forest. The artificial soil and water conservation forest construction and its mechanism on soil and \vater conservation have been studied at lanxi experimental station of soil and water conservation in zhejiang province from Apr.2001 to Jun.2002. This study was consisted of artificial soil and water conservation forest construction and its hydrological effect, the law of forest crown intercepting rainfall , the annual change of litter and its hydrological effect , soil anti-scourability intensified effect by artificial forest root system .the dimensional variation characteristic of soil physical peculiarity and microclimate variation character of artificial forest. The results showed as fellows 1 The artificial soil and water conservation forest construction and its soil and water conservation effect(l)The trend of forest height increase, chest diameter widen, crown layer gloomy degree rise was in consistent. This is to say, they all increased with growing season. But ihere were difference among different forest types .For phyllostachys pubescens ,its height slow increase, chest diameter relative stabilization, fallen leaves peak in Apr. and may; For mixed forests, forest height increase and chest diameter widen is slow. The change of crown gloomy degree was in consistent to fallen leaves; For cunning lanceolate , the speed of forest height increase exceed to chest diameter widen. The crown gloomy degree keep in very low. For citrus reticulate, the trunk of tree was low and its growth mainly embodied forest crown widen and gloomy degree rise.(2)The soil and water loss took on firstly rapid decrease, then slow decrease, finally keeping steady state. This dynamic law was embodied with these indexes of soil and water loss as follows. First, for phyllostachys pubescens .mixed forests and cunning lanceolate , the earth surface runoff didn’t obviously have appeared after three years since these forests were planted,but for normal citrus reticulate and dense citrus reticulate, the earth surface runoff didn’t have appeared after six years since these forests were planted, because normal citrus reticulate and dense citrus reticulate impaired the earth surface runoff in the process of them construction comparatively slow. Second. As a whole soil suspended matter little by little reduced with time prolonging of forest development .In the same time there were difference in different forests. These differences were classified two kinds. One kind was phyllostachys pubescens .mixed forests and cunning lanceolate .The dynamic change of their suspended matter had a obvious dividing points that is second years after forests planted. Before dividing point, the quantity of suspended matter was 93.7% of nine years total quantity. After dividingpoint, suspended matter quantity rapidly reduced .At fifth year there wasn’t suspended matter .The other kind was normal citrus reticulate and dense citrus reticulate. Their dividing points were at the third year.Before the dividing point, suspended matter quantity was 76.7% of nine years total quantity. After the dividing point, suspended matter slowly cut down. At ninth year there still was a little suspended matter. Third, the dynamic change of pushed matter differed in suspended matter, but all forest plots’ were in consistent .After the second year, there weren’t pushed matter in each forest plot. Fourth, the proportion of suspended matter and pushed matter in soil erosion total quantity decided their effect on the dynamic change law of soil erosion modulus. From the dynamic change of soil suspended matter and pushed matter in three years, the pushed matter was main in soil erosion at the first year. After the first year suspended matter took the place of pushed matter step by step. After the third suspended matter became main in soil erosion.2 the law of crown layer intercepting rainfall in different artificial更多还原