耕作对旱区坡耕地土壤碳素转化及冬小麦产量的影响

利用长期定位试验(1999开始保护性耕作,2004年采样测定),在豫西旱区坡耕地上进行了不同耕作对土壤有机碳、微生物态碳及水分利用效率的影响研究。结果表明:深松覆盖和免耕覆盖处理的耕层有机碳增加较明显,以深松覆盖有机碳含量最高为6.79gkg-1,比传统耕作高13.82%,其次是免耕,较传统高11.58%,而少耕却较传统降低了1.38%,随着土层的加深,土壤有机碳含量降低,0～60cm有机碳平均值,深松和免耕较传统分别增加了14.08%、5.41%,少耕较传统减少1.12%。土壤微生物碳对耕作敏感,其含量免耕>深松>传统>少耕,分别为206.87mgkg-1、138.43mgkg-1、115.42mgkg-1和112.57mgkg-1,较传统增加79.3%、19.9%和-2.5%。土壤有机碳和土壤微生物态碳都有坡下富集现象。少耕、免耕、深松和传统的SMBC/SOC的值分别为1.91%、3.11%、2.04%和1.93%,免耕和深松对培肥地力、改善环境有好的应用前景;同时免耕覆盖与深松覆盖可提高产量,增产分别达10.22%与9.26%;可提高水分利用效率。     

耕作方式对冬小麦棵间蒸发及水分利用效率的影响

通过田间试验研究了华北平原的山前平原区不同耕作方式下,冬小麦田间水分变化规律及对产量的影响,分析了不同耕作方式在节水中的作用。结果表明耕作方式对田间土壤水分动态变化的影响是显著的:传统深耕(CT),旋耕(RT),全免耕(NT),秸秆粉碎免耕(SNT)四种耕作方式对棵间蒸发的影响显著;秸秆覆盖免耕对抑制小麦棵间蒸发效果明显,其日蒸发强度仅为传统耕作的59%和旋耕的74%。耕作方式对土壤蓄水的作用差异主要发生在作物生育前期,对于不同土层主要影响耕层50 cm深的土壤剖面。免耕条件下冬小麦植株高度降低,生物量增加,但产量偏低;而深耕和旋耕的田间植株密度高,最终产量也最高。从水分利用效率综合考虑,旋耕是比较理想的耕作方式。     

宁夏南部山区秸秆覆盖对春玉米水分利用及产量的影响

为研究秸秆覆盖在宁南山区对春玉米生长及其土壤水分的影响,在宁夏彭阳县对三种不同秸秆覆盖处理方式进行了试验研究。对比分析了不同覆盖措施下春玉米的生长状况、产量及水分利用效率变化的关系。结果表明:采用秸秆覆盖方式可使春玉米的株高、穗位高、穗长、生物产量及经济产量等指标得到显著提高,土壤的蓄水保墒性能增强,水分利用效率提高,增产增效明显;与传统方式相比,整秸秆覆盖可使春玉米的产量及水分利用效率分别提高3.5%及16.5%。     

南方稻田保护性耕作的研究进展与研究对策

就保护性耕作的由来和内涵、国内外发展现状作一综述,在指出我国稻田传统耕作方式存在的主要问题后,着重介绍了南方稻田保护性耕作的主要技术模式:即以免(少)耕、秸秆还田为主的保护性耕作技术和休闲期保护性耕作技术。稻田免(少)耕保护性耕作技术主要包括水稻免耕直播、免耕抛秧、免耕套播和免耕小苗移栽技术;秸秆还田为主的保护性耕作技术主要包括秸秆覆盖免耕栽培水稻和秸秆覆盖免耕旱作技术;休闲期保护性耕作技术主要包括冬春休闲和休闲期绿色覆盖技术。指出这些保护性耕作技术不仅具有传统栽培同样或更高的产量潜力,而且省工、节本、能减少水土流失,保持和改善地力,经济、生态效益显著。分析稻田保护性耕作存在的不足之处,提出发展对策。     

基于TVDI的大范围干旱区土壤水分遥感反演模型研究

温度植被干旱指数TVDI(Temperature Vegetation Dryness Index)是一种基于光学与热红外遥感通道数据进行植被覆盖区域表层土壤水分反演的方法。当研究区域较大、地表覆盖格局差异显著时,利用TVDI模型来反演陆表土壤水分,精度通常较低。对Sandholt的TVDI土壤水分反演模型进行了改进:利用云掩膜校正和多天平均温度合成来减少云的影响;同时对研究区域地形起伏、覆盖类型差异的影响进行了消除;对TVDI模型干边的模拟方法进行了改进。最后,使用铝盒采样等方法利用新疆地区观测得到的地面数据来拟合改进后的模型参数,并对2009年5月和8月的土壤水分进行了反演实验。与实测数据的比较分析表明,该模型能基本满足大区域土壤水分反演的要求,改进后的模型对新疆地区的土壤水分估算精度有较显著的提高。     

极化分解技术在估算植被覆盖地区土壤水分变化中的应用

地表植被覆盖是影响雷达遥感估算土壤水分的主要因素之一。本文探讨了将极化分解技术与植被覆盖地区的一阶散射模型结合估算土壤水分变化的方法。雷达数据经极化目标分解技术分解后得到的双次散射项和一阶植被散射模型的植被-地表的双次散射项一一对应，再利用多时相雷达数据消除植被层后向散射的影响，从而估算出地表土壤水分变化量。最后应用全极化机载雷达数据（AirSAR）对该方法进行了检验，结果表明该方法能够较好的估算植被覆盖地表的土壤水分变化。     

覆盖免耕土壤棵间蒸发的研究

本文以翻耕、铁茬等常规耕作为对照,采用Micro-1ysimeter对覆盖免耕夏玉米田的土壤棵间蒸发进行了较为系统地研究。同翻耕、铁茬等相比,免耕有效地减少土壤棵间蒸发,免耕土壤日蒸发量最低,铁茬其次,翻耕最高;从阶段土壤棵间蒸发量变化看,翻耕的蒸发量较高,前期与免耕和铁茬差异较大,后期差异减小,免耕最低;从蒸发占蒸散的比例看,翻耕蒸发比例高,免耕比例最低。免耕可以有效地减少土壤蒸发量,增加作物蒸腾耗水。     

阴山北麓缓坡丘陵不同植被类型下土壤水分空间分布特征-以武川县为例

近年来由于农耕面积的进一步扩大,阴山北麓植被破坏程度加深,水蚀风蚀沙化现象日益严重。本文以内蒙古阴山北麓为研究对象,研究了这一地区缓坡丘陵的土壤水分分布特征及不同植被类型下土壤水分时空分布,为这一地区的生态治理过程中,植被类型、种植模式的选择提供数字依据。结果表明:(1)后山地区与内地相反,缓坡丘陵土壤水分以阳坡为最高,阴坡次之,顶部为最低;(2)该地区的土壤水分分布受植被类型等的影响,表现出一定的空间变异特性。     

基于改进温度植被干旱指数的农田土壤水分反演方法

基于植被指数-地表温度(VI-Ts)特征空间的温度植被干旱指数(TVDI)被广泛应用于土壤水分监测,但TVDI为土壤水分相对值,而且利用散点图确定干湿边会造成很大的不确定性。基于能量平衡方程和TVDI,该文提出一种定量干湿边选取方法和改进的TVDI模型——定量温度植被指数(Temperature Vegetation Quantitative Index,TVQI),以MODIS遥感数据为基础,实现了定量干湿边真实土壤水分的遥感估算。结果表明:TVQI估算结果与所观测土壤水分呈0.01水平显著相关,总体上的平均绝对误差小于0.02cm~3/cm~3,均方根误差RMSE小于0.035cm~3/cm~3;相对TVDI,TVQI克服了传统干边计算中对植被覆盖类型的限制,更能够准确反应土壤深度在0~10cm、10cm~20cm的土壤水分值,尤其与10cm~20cm土壤水分值更为贴近。     

一种利用土壤水分反演地下水位遥感方法

针对利用土壤水分在干旱地区反演一定植被覆盖下地下水位的局限性,采用遥感-数学-模型学融合的研究方法,以Landsat-8遥感图像作为数据源,提取改进型温度植被干旱指数,并与实测土壤水分建立土壤水分反演模型,然后结合土壤水分和地下水位的实验方程,引入土壤水分反演模型建立了一定植被覆盖条件下的地下水位分布遥感监测评价模型(GLDRS模型)。结果表明,土壤水分反演值和实测值的决定系数R2=0.65,均方根误差RMSE=3.22,能够达到实验精度要求;利用GLDRS模型对研究区地下水位反演结果取得较高精度,实测地下水位和反演地下水位的R2=0.81,RMSE=1.01。     

近20 a若尔盖湿地水土流失变化的遥感评估

在若尔盖湿地以1989、2000、2005和2010年的Landsat TM/ETM数据为信息源提取土地覆盖以及植被覆盖度信息,结合ASTER DEM数据,在地理信息系统技术空间分析功能的支持下,依据水利行业《土壤侵蚀分类分级标准》(SL190-2007),通过叠加分析对研究区近20 a水土流失变化状况进行评估并分析了其与沼泽萎缩的关系。研究结果表明:若尔盖湿地土壤水力侵蚀面积广,但是程度轻;2000年以前水土流失程度加重,泥沙淤积是沼泽快速萎缩的原因之一;之后在相关生态环境建设和恢复措施作用下水土流失程度有所减轻,沼泽萎缩也呈减缓趋势。     

Environmental cost of soil erosion in Sri Lanka: tax/subsidy policy options

The on-site and off-site impacts of land degradation, particularly in the form of soil erosion, pose a serious problem in many developing countries. In Sri Lanka, the implementation of wide-ranging policy reforms and institutional changes designed to move the country toward an outward oriented market economy, have strengthened concerns about environmental degradation and the sustainability of the country's natural resource base. The environmental impact of many of the policy reforms and economic changes are determined by complex economy-wide, inter-sectoral interactions. A computable general equilibrium model incorporating soil erosion is developed to analyse the impacts of various policy reforms in Sri Lanka. Our analysis establishes three important results. First, economic losses from soil erosion in Sri Lanka are substantial. Second, trade liberalisation reforms increase national income and marginally reduce soil erosion. Third, while trade liberalisation has a positive impact on soil erosion, complementary policies which directly target soil erosion, such as tax/subsidy incentives, are needed to minimise social losses from soil erosion.     

Changes in the soil erosion status in the middle and lower reaches of the Yangtze River basin from 2001 to 2014 and the impacts of erosion on the water quality of lakes and reservoirs

ABSTRACT

The revised universal soil loss equation (RUSLE) was used to obtain the soil erosion intensity distribution in the middle and lower reaches of the Yangtze River basin (MLYB), where the input data included a digital elevation model (DEM) and Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing products. Changes in the soil erosion intensity throughout the MLYB were analysed from 2001 to 2014, and the potential influences of these changes on the local water quality of lakes and reservoirs were revealed. This investigation is the first to reveal the spatial and temporal changes in soil erosion throughout the MLYB. The results indicated that from 2001 to 2014, most of the MLYB was characterized by slight and light soil erosion levels, whereas relatively few areas exhibited intensive to severe soil erosion. Soil erosion in the MLYB displayed a decreasing trend from 2001 to 2014; over 80% of the region displayed a decreasing soil erosion intensity change rate, indicating that soil conservation in most of the MLYB has improved over the past 14 years. However, 12.8% of the area presented an increasing change rate, and the region with the maximum increasing change rate was located mainly in the lower Yangtze basin. Furthermore, spatial heterogeneities were found in the soil erosion intensities throughout the MLYB: soil erosion improved in the upper and middle regions of the MLYB, whereas soil erosion worsened in the lower regions of the MLYB. Among the sub-basins of the MLYB, obvious soil erosion occurred most frequently in the Hanjiang basin and least frequently in the Taihu basin. A driving force analysis showed that the influence of precipitation on soil erosion is more evident than that of human activities in all sub-basins except the Dongting basin. A correlation analysis between soil erosion and water turbidity/water transparency showed that 45.9% of the decreasing water turbidity is correlated with decreasing soil erosion and that 42.5% of the increasing water turbidity might be influenced by increasing soil erosion. Decreased soil erosion might be responsible for the improved water transparency for 50% of the lakes, whereas increased soil erosion is correlated with a decrease in water transparency for over 50% of the lakes.     

Study on Dynamic Remote Sensing Monitoring of LUCC and Soilwind Erosion Intensity in the Beijing-Tianjin Sandstorm Source Control Project Region

The Land Use/Cover Change(LUCC) and soil wind erosion intensity of the Beijing\|Tianjin sandstorm source control project region were monitored by remote sensing.The spatial and temporal patterns of LUCC and soil wind erosion in the project region were analyzed.The results showed that there was significant difference in LUCC and soil erosion intensity before and after the project was implemented.In the recent 30 years,the LUCC process mainly manifested the change from cultivated land reclamation to ecological conversion of farmland to forest and grass,with the ecological restoration and desertification effectively inhibited.The overall arable land showed an increase and then decreased.The area of arable land increased from 2000 to 2015,the area of cultivated land converted to forest and grassland was 446.10 km² and 1 129.32 km²,with the most obvious in the west;the area of land for construction expanded obviously;the trend of unutilized land decreased significantly The type of conversion is dominated by grassland conversion to grassland with an area of 493.12 km².The erosion-mitigating modulus of soil erosion in the project region with wind-blown sand control decreased overall,especially after the implementation of ecological engineering (p<0.001).The eastern and southern areas are covered with high-coverage grassland and soil wind erosion in the area with the main type is small;Soil wind erosion in the Hunshandake sandy land is larger,but the overall trend is decreasing.Different land use/cover types have a greater impact on soil wind erosion intensity.The order of soil wind erosion modulus is Sandy land> Sparse grass> Moderate grass>dryland> Shrub>Paddy>Dense grass> Other woods> Sparse woods> Forest;The conversion of low coverage to high coverage grassland types effectively inhibited soil erosion (-66.12%),and the increase of vegetation coverage effectively reduced soil erosion.The soil wind erosion increased (58.26%) in the surrounding area of sandy area,the soil wind erosion increasedduring the conversion process of low coverage grassland type,and the grassland was converted into sand,and the wind erosion in the dry land increased.     

基于遥感数据的流域土壤侵蚀强度快速估测方法

以北京延庆县境内的妫水河流域为例, 提出了一种基于遥感数据的土壤侵蚀强度快速估测方法。首先, 利用遥感数据和植被指数模型提取流域内土地利用类型信息和植被覆盖度信息; 其次, 利用数字高程模型数据生成坡度图; 然后, 结合土壤侵蚀强度分级指标, 将坡度图与土地类型图、植被覆盖度图空间叠加, 判断和计算侵蚀强度等级, 结果获得了流域土壤侵蚀强度等级图; 最后, 计算了流域的年平均侵蚀模数。结果表明, 妫水河流域的土壤侵蚀以微度和轻度为主, 所占面积比例为74.88% , 极度和剧烈侵蚀很少, 不到总面积的2%。整个流域的年侵蚀模数估计为1 74611/ km ²·a。     

济南山丘区地貌演化与水土流失研究

水土流失,其实是一种主要的侵蚀地貌演化过程。本文以戴维斯提出的地貌侵蚀循环学说为基础,把高程-面积分析法运用到流域地貌发育研究之中,把济南山丘区地貌发育阶段分为壮年期和老年期。各流域土壤侵蚀危险度平均值、土壤侵蚀强度综合指数的大小次序与其地貌发育阶段呈现良好的对应关系,说明尽管人类活动是加剧土壤侵蚀的主要原因,但地貌发育过程对土壤侵蚀的影响同样不可忽视。     

卫星遥感技术在永定河流域（河北）土壤侵蚀调查评价中的应用研究

利用Landsat-5TM图像,在分析土壤侵蚀影响因素的基础上,首先进行与土壤侵蚀相关密切的各单项要素的解译;其次,以土壤侵蚀在TM图像上的综合反映为标志进行基本侵蚀图斑的综合解译;第三步通过选定的的土壤侵蚀强度评判模型,对每个基本侵蚀图,由不同权重的各单项要素给出其分值,最后根据综合分值确定每个图斑的土壤侵蚀强度等级。研究结果表明,冀西北地区土壤侵蚀是非常严重的,以轻度侵蚀为下限的侵蚀区面积占全区面积的65％。两大地貌单元区相比,盆地区更严重于山地区。但多时相对比研究也表明,近十几年的治理工作取得了明显成效,土壤蚀的总趋势是向减缓方向发展。     

Soil erosion assessment and simulation by means of SGEOS and ancillary digital data

Abstract

Due to soil erosion processes fertile soils are washed out almost anywhere in the world. Soil erosion protection measures are necessary, especially for food security reasons. This study uses the well-known Universal Soil Loss Equation (USLE) to assess the long-term soil erosion in a small catchment area and to simulate various soil protection alternatives. After completion at this test site the techniques can be applied for larger regions to detect areas that are most afTected by soil erosion and to guide precisely the efficient soil erosion prevention measures that proved to be valuable according to the computer simulation results.

This raster-oriented study uses a very accurate multi-temporal land-use classification to determine the land-cover (C-factor). The other input variables have been determined from ancillary data (e.g., digital elevation model and soil data). The compiled data layers of this geographical information system (GIS) allow the calculation of the long-term soil erosion per pixel as well as inquiries about all data layers for every pixel.

In addition to the resulting soil erosion risk map it is possible to simulate soil protection measures with the computer. This ensures that only the most effective ones are introduced to the field.     

前期含水量对坡面降雨产流和土壤化学物质流失影响研究

在防止土壤侵蚀条件下,利用室内人工降雨实验,研究了土壤初始含水率对坡面降雨入渗、产流、溶质迁移规律的影响。结果表明:初始含水率越高,产流越快,达到稳定入渗率的时间也越短。在初始含水率不同时次降雨过程中养分的流失量与初始含水量具有较强的相关性。磷浓度的变化范围主要在5cm以内,随着含水量的增加有效磷向土壤中迁移的总量增加。随着含水量的增加土壤钾离子向土壤中迁移的总量减小。在相同条件下,EDI值大小顺序是:磷<钾<溴。     

基于B/S的水土保持信息查询系统的设计和实现*

地理空间信息技术(WebGIS)的飞速发展,给水土保持信息监测和管理提供了新的手段和方法。为有效管理水土保持信息,在对水土保持信息的数据库设计和数据组织、关键功能设计等的基础上建立了一个基于B/S的水土保持信息查询系统,系统采用Oracle＋ArcSDE+ArcIMS体系构架实现了空间数据的五类查询方式：位置查询、条件查询、名称查询、空间关系查询、模糊查询;特别地设计和实现了地面监测数据的双向查询功能。水土保持决策管理者通过网络可以对各种模型方法估算的水土流失结果进行定量评价和专题统计分析,极大地提高了管