共查询到17条相似文献，搜索用时 375 毫秒
1.
坝地土肥水足 ,抗旱能力强 ,是黄土丘陵沟壑区发展高产、优质、高效农业的理想境地。但是 ,该区雨热同步、暴雨洪水集中 ,6— 9月份坝地常常遭受洪涝灾害 ,如何作到防洪保收 ,有许多问题值得探讨。本文以山西省离石市王家沟流域为例 ,通过实地调查、定位观测试验 ,得出如下结论 ,坝地次洪水淹水深度 <0 .7m、淹水历时 <7天 ,对玉米、高粱等高干作物生长影响不大 ,可以作为坝地防洪保收的标准 ;也可以作为今后进行沟道坝系工程建设、合理设计排洪渠断面尺寸的科学依据。 相似文献
2.
无定河流域典型淤地坝水资源效应比较研究——以辛店沟、韭园沟和裴家峁为例 总被引：3，自引：0，他引：3
通过实地考察,应用无定河流域典型淤地坝土壤水分的实测记录和统计分析方法,对淤地坝的水资源效应进行了探讨。研究发现总体上淤地坝的土壤含水率韭园沟高于裴家峁沟高于辛店沟,支沟坝低于主沟坝,在一定的深度基本上会存在较明显的湿土层或干土层,土壤含水率在坝地中部变化比较平缓,在6m以内随着土层深度的增加,土壤水分含量基本上呈现增长趋势,在坝地中尾部某一深度会达到稳定状态。淤地坝蓄水减水效益非常明显,辛店沟、韭园沟和裴家峁流域坝系土体的总贮水量分别为5.14×104m3、63.67×104m3和15.21×104m3,蓄水效益分别为39.39%、20.94%和8.85%,减水效益分别为48.27%、44.06%和38.16%。辛店沟流域淤地坝约减少地表水资源9.87×104m3。三个流域所有淤地坝至少可以减少地表水资源88.75×104m3,对无定河径流量减少的贡献率为0.093%。淤地坝的这种土壤水分效应和蓄水减水效应是人为因素对水资源影响的一个重要表现。 相似文献
3.
王宏 《干旱区资源与环境》1998,12(3):58-63
在黄土高原丘壑区打坝淤地已成为一项行之有效的水土保持治沟工程措施,具有防洪减灾、固沟拦泥、减少入黄泥沙、调整土地利用结构、增田增产、改善生态环境等多重效益。截止１９８９年底,该区已建成淤地坝１１０８３座,已淤实有累计坝地面积１．０９６万ｈｍ２。１９５６～１９８９年３４年间,淤地坝累计减洪量８．２５６亿ｍ３,减少入黄泥沙７．１３４亿ｔ。 相似文献
4.
基于粮食需求的黄土高原地区淤地坝建设规模与论证 总被引：4，自引：0，他引：4
从黄土高原地区粮食需求、总来沙量和建设能力三方面论证了黄河流域黄土高原地区淤地坝的建设规模。结果表明:黄土高原地区到2020年共需布设淤地坝16.3万座,其中骨干坝2.7万座,中小型淤地坝13.6万座;到2020年黄土高原地区将新增加坝地面积49.5万hm2,可退耕陡坡地297万hm2,退耕面积占2000年黄土高原地区坡耕地总面积823万hm2的36%。因此,《黄土高原地区水土保持淤地坝规划》提出的到2020年的淤地坝建设目标切实可行。 相似文献
5.
本文采用实地取样、测试及整理已有资料的方法,研究绥德县辛店沟中的淤地坝对土壤含水量及地表径流的影响。通过对研究区两个坝地中土壤含水量的分析、计算得出:土壤含水量随深度的增加而逐渐增加,但增加幅度不大;主干坝坝地中的土壤含水量较支沟坝多1.89%,这与韭园沟的不同;而在同一坝地中各部位因地表覆盖、地下水补给等的不同,使其变化曲线的变幅及变化趋势也不同,坝地中部土壤含水量最高,主、支沟坝地中部平均含水量分别为11.88%和12.97%;主、支沟坝静态含水量分别为0.88938万m3、1.03032万m3,辛店沟总蓄水量为23.0484万m3。 相似文献
6.
淤地坝坝系布设是较复杂的问题,涉及影响因子较多,其中很多是不能定量的模糊因素。本研究利用模糊综合评判数学方法来建立优化模型,在客观评价各项指标的基础上,结合实例将淤地坝坝系布设方案中的生态指标和社会指标等所包含的模糊因素进行定量分析,比较客观科学地选择出了最优布设方案。 相似文献
7.
<正>"萝卜为十字花科萝卜属1~2年生蔬菜作物。原产我国,因其适应性强,栽培容易,产量高,用途广,可生食、熟食、腌渍、晒干等深受生产者和消费者喜爱,栽培面积大,是根菜类蔬菜主要种类之一。潼南作为重庆最大的蔬菜产业基地,萝卜大多栽培于涪江及琼江沿岸的冲积坝地,常年栽培面积7 667 hm~2,产量46万吨、产值3.68亿元。产品不仅满足重庆主城及区县消费, 相似文献
8.
黄土高原丘陵沟壑区淤地坝的减水减沙效益分析 总被引：14，自引：0，他引：14
根据皇甫川、窟野河、佳芦河、秃尾河、大理河五条支流共 4877座淤地坝的调查资料 ,分析了单坝、坝系减水减沙效益 ,暴雨毁坝增沙情况 ,以及与其影响因素之间的关系 ,可为黄土高原的淤地坝设计标准、坝系建设规划、流域效益评价、土地资源的合理利用提供依据 相似文献
9.
以延安碾庄沟小流域为研究对象,对该小流域内梯田地与坝地的土壤水分特征进行分析.结果表明,梯田地与坝地的土壤水分垂直分布有着相似的特点,梯田地和坝地土壤水分的垂直变化可以分为4个层次:土壤水分剧变层;土壤水分活跃层;土壤水分次活跃层;土壤水分相对稳定层.坝地的土壤含水量高于梯田地,且不同的作物类型可以引起土壤水分的变化,说明作物类型与土壤水分状况有一定的关系. 相似文献
10.
黄土丘陵沟壑区人工农田土壤钾素特征研究 总被引：3，自引：0，他引：3
通过土样分析,利用统计分析法系统研究了黄土丘陵沟壑区人工农地——坝地和梯田的土壤钾素含量、相关性、垂直和时空分异特征。研究结果表明:坝地和梯田钾素分布严重失衡;表层速效钾平均含量坝地属"中等",梯田属"缺乏";表层全钾平均含量坝地属"较高",梯田为"中等";缓效钾平均是速效钾的7.58倍(坝地)和11.06倍(梯田),但转化率较低;矿物钾平均占全钾的95.71%(坝地)和95.16%(梯田),却难以被作物利用。土壤各形态钾素间都呈极显著正相关,并受土壤有机质、CEC、pH值和颗粒组成的影响。表层与下层间的速效钾、坝地和梯田间的缓效钾都有极显著差异,但黄土母质土壤钾素整体分布均一;坝地速效钾沿剖面向下含量增加,且整体高于梯田;坝地因高耗钾作物玉米而导致缓效钾含量低于梯田。土壤有效性钾、速效钾和缓效钾在时间动态上都表现为先增后降,分水岭年限坝地约在40 a,梯田约在30 a。 相似文献
11.
景可 《干旱区资源与环境》1995,9(3):74-79
本文分析了黄河中游半干旱区黄土丘陵地区的自然条件与环境特征，提出在黄土丘沟区以淤地坝的方式，建立黄土高原半干旱地区独特的绿洲。文中较全面的分析了该区建设绿洲的必要性与可能性，以及持续发展的有关问题。 相似文献
12.
F. J. Simmonds 《国际虫害防治杂志》2013,59(1):41-43
A survey was conducted to gain insight into the perceptions of Lesotho's farmers with regard to insect pests of maize and sorghum, to identify management practices that could impact on stalk-borer numbers and to shed light on other farming practices such as variety selection and crop residue management. Field studies were conducted to determine the incidence and distribution of Busseola fusca (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Pyralidae) larvae in sorghum and maize residues and to determine the effect of certain crop residue management practices on stalk-borer survival. Results indicated that farmers regard stalk-borers as important pests that sometimes need to be controlled. However, most farmers never apply control measures, mainly due to lack of resources. Residues of maize and sorghum plants are largely used as animal fodder with maize being cut and fed to animals after harvest. Sorghum crop residues are largely left on fields after harvest to be used by free-grazing animals. While stacks of maize stalks were not important in the winter survival of B. fusca larvae, stacking of sorghum ensures winter survival of C. partellus larvae. Detasselling of maize plants is commonly done at plant senescence and the upper halves of plants are fed to animals. Detasselling of maize plants had no effect on the number of borer larvae in plants at harvest. 相似文献
13.
Land cover in the Chinese Loess Plateau has undergone dramatic changes since the late 1980s.Revealing the trend in land cover change and eco-environmental quality response of different geomorphic units in this stage is a realistic requirement for promoting sustainable development of the Chinese Loess Plateau.Based on the data of geomorphic units and land cover in 1990,2000,2010 and 2018 of the Chinese Loess Plateau,we studied the trend of land cover change and eco-environmental quality response of different geomorphic units by using a significance index of land cover change,a proportion index of land cover change and an eco-environmental response model.The results indicated that from 1990 to 2018,the areas of forestland and construction land substantially increased,whereas those of cropland,grassland,wetland and unused land considerably decreased.Land cover change exhibited large geomorphic differences,and the main conversion of land cover was from cropland into other land types.Unstable trend of land cover change in the loess tablelands and sandy loess hills declined,whereas the unstable trends in the other geomorphic units enhanced.Eco-environmental quality varied among different geomorphic units.The expansion of construction land and degradation of forestland,grassland and wetland resulted in the deterioration of eco-environmental quality.The conversion of cropland and unused land into forestland and grassland,and the conversion of grassland into forestland were the main factors that drove the improvement of eco-environmental quality.The findings of this study may provide theoretical reference and support decision making for the optimization of land use structure and the improvement of eco-environmental quality on the Chinese Loess Plateau. 相似文献
14.
新疆库车县耕地人口承载能力研究 总被引：4，自引：0，他引：4
库车县地处南疆腹地。由于库车县人口增长过快 ,造成耕地资源的过度利用 ,导致土地退化、环境恶化。因此 ,确定适当人口规模 ,对库车县耕地资源和干旱区绿洲生态环境保护至关重要。本文根据库车县光、温、水、土生产潜力 ,折算库车县耕地人口承载能力 ,试图确定在不同生活水平要求下库车县适当的人口规模 ,为库车县农业资源的合理开发利用提供参考依据 相似文献
15.
Tadele Tefera 《国际虫害防治杂志》2013,59(1):35-40
A survey of 90 farmers, randomly selected over six sorghum-growing districts in eastern Ethiopia was carried out during July to August, 2001 in the long rainy season. The study investigated farmers' perceptions of the importance of stem-borer and farm practices influencing the pest. Sorghum farming was characterized by smallholdings with an average land size of 4.3 ha, an average family size of 6 and an average yield of 878?kg ha???1. Farmers cited pests, drought, and shortage of seed, land and labour as the main constraints upon sorghum production. Stem-borers were perceived to be the major pests requiring control. The majority of the farmers never applied chemical insecticides against stem-borers due to lack of capital and unavailability of insecticides. Because of restricted access to improved varieties, farmers largely used local cultivars of sorghum selected for yield potential but with little emphasis on insect resistance. Very few farmers destroyed sorghum residues after harvest. The majority of farmers grew sorghum under intercropping mainly due to the high yield expected. Crop rotation in sorghum fields was not widely practised due to land shortage. 相似文献
16.
The impact of land use change on soil organic carbon and labile organic carbon stocks in the Longzhong region of Loess Plateau 总被引：3，自引：0，他引：3
LiHua ZHANG 《干旱区科学》2012,4(3):241-250
Land use change (LUC) is widely recognized as one of the most important driving forces of global carbon cycles. The soil organic carbon (SOC) and labile organic carbon (LOC) stores were investigated at arable land (AL), artificial grassland (AG), artificial woodland (AW), abandoned arable land (AAL) and desert steppe (DS) in the Longzhong region of the Loess Plateau in Northwest China. The results showed that conversions from DS to AL, AL to AG and AL to AAL led to an increase in SOC content, while the conversion from DS to AW led to a decline. The differences in SOC content were significant between DS and AW at the 20-40 cm depth and between AL and AG at the 0-10 cm depth. The SOC stock in DS at the 0-100 cm depth was 39.4 t/hm 2 , increased by 28.48% after cultivation and decreased by 19.12% after conversion to AW. The SOC stocks increased by 2.11% from AL to AG and 5.10% from AL to AAL. The LOC stocks changed by a larger magnitude than the SOC stocks, which suggests that it is a more sensitive index of carbon dynamics under a short-term LUC. The LOC stocks increased at 0-20 cm and 0-100 cm depths from DS to AW, which is opposite to that observed for SOC. The proportion of LOC to SOC ranged from 0.14 to 0.20 at the 0-20 cm depth for all the five land use types, indicating low SOC dynamics. The allocation proportion of LOC increased for four types of LUC conversion, and the change in magnitude was largest for DS to AW (40.91%). The afforestation, abandonment and forage planting on arable land led to sequestration of SOC; the carbon was lost initially after afforestation. However, the carbon sink effect after abandonment may not be sustainable in the study area. 相似文献