共查询到19条相似文献，搜索用时 171 毫秒
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黄土丘陵区小流域土壤氮素流失规律 总被引：19，自引：0，他引：19
以８．２７ｋｍ＾２纸坊沟流域和１：４００比例流域模型为研究对象,研究小流域土壤氮素随径流流失规律。结果表明：在模拟降雨下,当流域植被覆盖度分别为６０％、４０％、２０％和０时,流域模型土壤铵态氮流失量分别为８７．０８、４４．３１、２５．１６和１３．７１ｋｇ／ｋｍ＾２,硝态氮为８５．５０、７４．０５、６３．９５和５６．２３ｋｇ／ｋｍ＾２,全氮为０．８１、１．１８、１．９８和７．５１ｔ／ｋｍ＾２;在自然 相似文献
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差不嗄蒿在科尔沁沙地草场植被中的作用 总被引：6，自引：0，他引：6
差不嗄蒿是科尔沁沙地草场退化过程中的一个重要缓冲种。在草场退化过程中能够迅速占邻退出植物种遗留下来的空间，生物量由８１．６ｇ／ｍ＾２增加到２８５ｇ／ｍ＾２；但从半固定沙丘草场到半流动沙丘草场，其生物量减少到了１９０ｇ／ｍ＾２，占总生物量的７７．２％。 相似文献
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影响降雨击溅侵蚀过程的多元回归正交试验研究 总被引：11，自引：2，他引：9
根据多元正交设计,对马兰黄土进行了降雨(人工模拟)溅蚀试验。得到了计算降雨溅蚀分散量(Y)和降雨溅蚀向下坡搬运量(Z)的两个回归方程。方程揭示影响降雨击溅侵蚀诸因素之间的交互作用,以及各个因素在降雨溅蚀过程中的地位和对各种降雨溅蚀临界值的明显影响。 相似文献
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黄土高原粮食生产潜势与高产技术研究 总被引：1，自引：0，他引：1
从黄土高原地区粮食发展历史经济和十多年来科技攻关实践及生产潜力的调查和试验证明,该区域在资源潜力的技术潜力上有能力达到粮食自给。据中科院水土保持研究所在长武站试验。１９９３年在正常降水的情况下,小麦产量４９４４ｋｇ／ｈｍ＾２,玉米产量９４７８．５ｋｇ／ｈｍ＾２,两料产量达１４４２２．５ｋｇ／ｈｍ＾２（９６１．５ｋｇ／亩）,创区历史最高记录。通过多方面的努力,黄土高原粮食生产连续上了几个台阶,其中选 相似文献
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我国西南地区的水供应和粮食生产潜力 总被引：1，自引：1，他引：0
我国西南地区天然水源非常丰沛,总的可利用量达９４００亿ｍ＾３／ａ,但工程调节能力较低,实际用水量仅为资源蕴藏的１０％。农业灌溉是其主要耗水方式。西南五省（市、区）耕地约１６７００万亩（约１１１３万ｈｍ＾２）,有效灌溉面积占其中的４２％,人均有效灌面积仅０．４亩（约０．０４４８ｈｍ＾２）。今后粮食生产的潜力在于进一步发展水利工程,提高有效灌溉面积。在未来的１０年可增加灌面近１５００余万亩,约可增加粮 相似文献
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坡面溅蚀发生过程及其与坡度关系的模拟研究 总被引：11，自引：0，他引：11
通过人工模拟降雨试验,分别观测降雨过程中不同方向上溅蚀强度的变化,根据各影响因子间相互消长及相互制约的关系特点,分析了雨滴溅蚀发生的过程特征及其变化原因,从溅蚀过程的变化特点及溅蚀强度的变化规律比较,定量地探讨了坡度对雨滴击溅侵蚀的影响作用,得出了溅蚀强度与坡度因子之间的关系方程。 相似文献
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南极中山近岸海水生态学研究Ⅰ.1992年冰藻生物量的垂直分布及季节变化 总被引：3，自引：1，他引：3
从１９９２年４月１２月对东南极中山近央求发年冰生物是及其环境因子进行了预测。冰底有色层出现在４月下旬和１１月下旬，集中于冰底２－３ｃｍ，叶绿素α最高含量分别为８８．３ｍｇ／ｍ＾３和２８１０ｍｇ／，＾３，相应的冰藻数量分别为３．５×１０＾６和１．２１×１０＾８个／升。 相似文献
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以福建省长汀县河田地区为研究区,在野外样方生物量调查和典型植被光谱测定基础上,对比分析SPOT5影像8种植被指数与马尾松林(Pinus massoniana)碳储量关系,估算区域尺度马尾松林碳储量。结果表明,马尾松林冠层与林下植被芒萁(Dicranopteris dichotoma)在短波红外波段(SWIR)反射率区分明显。加入SWIR的修正的归一化植被指数(MNDVI)与森林碳储量回归决定系数最高,并有较小的均方根误差,同时可减少林下植被覆盖对马尾松林碳储量估算影响。生态恢复驱动下研究区平均碳储量增加到30.37 t/hm2。 相似文献
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祁连山青海云杉林截留对降水的分配效应 总被引：8，自引：0，他引：8
为了评估青海云杉林的水源涵养服务功能,选择祁连山西水林区排露沟流域青海云杉林,定位监测了在2006年中共83次降水事件的截留分配效应,观测期降水总量为394.2 mm,林冠截留、茎流和穿透水量分别是139.1、1.96和253.1 mm,林冠截留率、茎流率、穿透率分别为35.28%、0.50%和64.22%,当林外降水量>0.8 mm时才观测到林内穿透雨,而大于13.60 mm时,才观测到树干茎流。林冠对降水的截留分配与降水量、降水形态以及林分特征密切相关。冠层截留量、茎流量和穿透量与降水量均呈正相关,冠层截留率与降水量呈负相关,而茎流率和穿透率呈正相关;林冠对降雪的截留强于降雨,而降雨的穿透量强于降雪,同一降水事件下树干茎流量随着胸径的增大而增加。青海云杉林冠的几何形态结构(枝叶的分布与排列)不利于形成树干茎流。 相似文献
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Soil erosion has become a serious environmental problem worldwide, and slope land is the main source of soil erosion. As a primary cover of slope land, crops have an important influence on the occurrence and development of runoff and soil erosion on slope land. This paper reviews the current understanding of runoff and soil erosion on slope cropland. Crops mainly impact splash detachment, slope runoff, and sediment yield. In this review paper, the effects of crop growth and rainfall on the splash detachment rate and the spatial distribution of splash detachment are summarized. Crop growth has a significant impact on runoff and sediment yield. Rainfall intensity and slope gradient can influence the level of erosive energy that causes soil erosion. Furthermore, other factors such as antecedent soil water content, soil properties, soil surface physical crust, and soil surface roughness can affect soil anti-erodibility. The varying effects of different crops and with different influence mechanisms on runoff and soil erosion, as well as changes in their ability to influence erosion under different external conditions should all remain focal points of future research. The effect of crop vegetation on runoff and soil erosion on slope land is a very important factor in understanding large-scale soil erosion systems, and in-depth study of this topic is highly significant for both theory and practice. 相似文献
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江西泰和县森林生态系统水源涵养功能评估 总被引：8，自引：0，他引：8
森林生态系统综合水源涵养能力是林冠层、枯落物层和土壤层蓄水能力的总和。本文根据江西泰和县 2003 年森林资源二类调查,结合文献收集,从3 个作用层评估了泰和县森林生态系统的水源涵养量及其空间分布格局,比较了不同森林类型、林龄、海拔、坡度下的林冠降雨截留能力,枯落物最大持水量和土壤蓄水能力。结果表明,林冠层平均截留率为16.31%,枯落物层持水率为2.14%,土壤层蓄水率为81.55%,3 个层次总截留和蓄水量为1.41 亿m3。各种森林类型水源涵养量由大到小依次为：杉木林>马尾松林>湿地松林>阔叶林>毛竹林>灌木林> 混交林>经济林。幼林龄、中林龄、近熟林、成熟林和过熟林水源涵养贡献率分别为17.58%、65.39%、14.18%、 2.48%和0.37%,涵养水源能力随林龄的增加而增加。空间上,泰和县森林生态系统的综合水源涵养力表现出从东西两侧向中部递减的分布。不同立地条件下林分的合理经营与管理对于整个森林生态系统水源涵养功能的发挥具有重要的作用。 相似文献
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Rainfall interception is of great significance to the fully utilization of rainfall in water limited areas.Until now,studies on rainfall partitioning process of typical ecosystems in Heihe River Basin,one of the most important inland river basins in China,is still insufficient.In this study,six typical ecosystems were selected,namely alpine meadow,coniferous forest,mountain steppe,desert,cultivated crop,and riparian forest,in Heihe River Basin for investigation of the rainfall interception characteristics and their influencing factors,including rainfall amount,duration,and intensity,based on the gross rainfall and high temporal resolution soil moisture data obtained from 12 automatic observation sites.The results show that the average interception amount and average interception rate of the six ecosystems are significantly different: alpine meadow 6.2 mm and 45.9%,coniferous forest 7.4 mm and 69.1%,mountain steppe 3.5 mm and 37.3%,desert 3.5 mm and 57.2%,cultivated crop 4.5 mm and 69.1%,and riparian forest 2.6 mm and 66.7%,respectively.The rainfall amount,duration,and intensity all had impact on the process of rainfall interception.Among these three factors,the impact of rainfall amount was most significant.The responses of these ecosystems to the rainfall characteristics were also different.Analyzing rainfall interception with high temporal resolution soil moisture data is proved to be a feasible method and need further development in the future. 相似文献
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高寒河谷灌丛冠层降雨再分配特征及影响因素 总被引：1，自引：0，他引：1
通过植被冠层的降雨被分割成冠层截留、穿透雨和树干茎流3个部分,这个过程（冠层降雨再分配）是高寒河谷灌丛生态演变的关键驱动因子之一,对于认识高寒河谷灌丛的水文循环过程及水分收支规律也具有重要意义。选取青海湖流域最重要的河谷灌丛--具鳞水柏枝作为研究对象,通过野外定点观测,深入分析了冠层降雨再分配特征及影响因素\.结果显示:①穿透雨量、树干茎流量、冠层截留量占同期降雨量的比例平均为48.40%、4.04%和47.56%,并在不同降雨量等级之间存在显著差异;②冠层降雨再分配各组成要素（穿透雨、树干茎流、冠层截留）与降雨特征参数存在高度相关性,伴随降雨量和降雨历时的增加,穿透雨量、树干茎流量、冠层截留量占同期降雨量的比例均逐渐趋于稳定,极限稳定值分别介于60.45%～61.07%、6.45%～7.42%、33.11%～34.17%;③产生穿透雨和树干茎流的临界降雨量分别为1.10 mm和1.87 mm,表明2 mm以下的降雨对土壤水分的补给基本没有贡献。因此,高寒河谷灌丛冠层降雨再分配与其他林木类型存在明显差异,需要深入研究其内在机制及水分利用规律。 相似文献
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Influence of canopy and topographic position on soil moisture response to rainfall in a hilly catchment of Three Gorges Reservoir Area,China 总被引：2，自引：0，他引：2
Liu Muxing Wang Qiuyue Guo Li Yi Jun Lin Henry Zhu Qing Fan Bihang Zhang Hailin 《地理学报(英文版)》2020,30(6):949-968
Rainfall provides essential water resource for vegetation growth and acts as driving force for hydrologic process, bedrock weathering and nutrient cycle in the steep hilly catchment. But the effects of rainfall features, vegetation types, topography, and also their interactions on soil water movement and soil moisture dynamics are inadequately quantified. During the coupled wet and dry periods of the year 2018 to 2019, time-series soil moisture was monitored with 5-min interval resolution in a hilly catchment of the Three Gorges Reservoir Area in China. Three hillslopes covered with evergreen forest(EG), secondary deciduous forest mixed with shrubs(SDFS) and deforested pasture(DP) were selected, and two monitoring sites with five detected depths were established at upslope and downslope position, respectively. Several parameters expressing soil moisture response to rainfall event were evaluated, including wetting depth, cumulative rainfall amount and lag time before initial response, maximum increase of soil water storage, and transform ratio of rainwater to soil water. The results indicated that rainfall amount is the dominant rainfall variable controlling soil moisture response to rainfall event. No soil moisture response occurred when rainfall amounts was 8 mm, and all the deepest monitoring sensors detected soil moisture increase when total rainfall amounts was 30 mm. In the wet period, the cumulative rainfall amount to trigger surface soil moisture response in EG-up site was significantly higher than in other five sites. However, no significant difference in cumulative rainfall amount to trigger soil moisture response was observed among all study sites in dry period. Vegetation canopy interception reduced the transform ratio of rainwater to soil water, with a higher reduction in vegetation growth period than in other period. Also, interception of vegetation canopy resulted in a largeraccumulated rainfall amount and a longer lag time for initiating soil moisture response to rainfall. Generally, average cumulative rainfall amount for initiating soil moisture response during dry period of all sites(3.5–5.6 mm) were less than during wet period(5.7–19.7 mm). Forests captured more infiltration water compared with deforested pasture, showing the larger increments of both soil water storage for the whole soil profile and volumetric soil water content at 10 cm depth on two forest slopes. Topography dominated soil subsurface flow, proven by the evidences that less rainfall amount and less time was needed to trigger soil moisture response and also larger accumulated soil water storage increment in downslope site than in corresponding upslope site during heavy rainfall events. 相似文献
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粤北石漠化地区坡地土壤侵蚀模拟试验研究 总被引：1，自引：0，他引：1
在粤北山区裸地、草坡地和耕地等3种石漠化土地的坡面上,采用0.3 mm·min-1、0.48 mm·min-1、0.72 mm·min-1、1.08 mm·min-1 4种降雨强度进行了36场人工降雨模拟试验。结果表明,坡面上3种类型石漠化土地的土壤侵蚀特征、强度各不相同。在同一地类上,土壤侵蚀量随降雨过程的进行呈现出波动下降的趋势,且随雨强的增大,土壤侵蚀量亦增大;土壤侵蚀量与雨强之间均呈现极显著的线性相关关系。在任一雨强条件下,都是裸地的土壤侵蚀量最大,耕地次之,草坡地最小。地表覆被对降雨侵蚀产沙过程有重要的抑制作用,大雨强条件下抑制作用尤为突出;而水平沟耕作方式能减少小雨强条件下的土壤侵蚀量,但随着雨强的增大,其影响也随之降低。 相似文献
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黄土区林草植被与降水对坡面径流和侵蚀产沙的影响 总被引：27，自引：0，他引：27
在一定地形地貌基础上,林草植被与降水是决定坡面产流产沙量的主要因素,而这些因素各因子之间合作用于坡地产流产沙,增加了影响机制的复杂性。为深入分析降水因子与林分结构因子对坡地降雨产流产沙的影响,为黄土区植被建设提供理论依据,对蔡家川流域典型样地的实验资料进行分析。结果表明,刺槐和油松林场降雨产流、产沙量与降雨量和降雨强度有较好相关性,但相关性随着林分郁闭度的增大而减小;当油松林林分郁闭度<0.6时,产流、产沙量与I30的相关性要更显著于与I10的相关性,而林分郁闭度在0.6以上时,则相反。在林分结构因子对坡面产流产沙的影响中,当林分覆盖度>40%时,林分减水减沙效益显著。林地枯落物和草本植物通过截持降水、增加地表糙率来削减坡面产流产沙量,刺槐和油松林地的枯落物年截流量占降雨总量的13.5%~22%。刺槐和油松林的稳渗速率随林分密度的增加而增大,但不与密度的增加幅度成正比,当刺槐、油松林的密度超过3 000株/hm2时,稳渗速率增加缓慢,从防蚀角度考虑,可将其作为林分密度的上限。在林分生物量>14.51 t/hm2时,植被具有极好的防护功能。通过对影响坡面产流产沙的影响因子的灰色关联分析,林分郁闭度和草本、枯落物生物量对坡面产流产沙影响显著,关联度值均>0.6。 相似文献