甘肃省土地在诉说

甘肃省地处黄土高原、蒙古高原、青藏高原和秦巴山地交汇过渡地带,呈西北向东南延伸,地势高亢,地形复杂多样,东南部山高谷深、重峦叠嶂。境内的水系分属黄河、长江和内陆河三大流域。省内河流平均年输沙量6.44×108t。甘肃省的水土流失类型主要有:水力侵蚀、风力侵蚀、重力侵蚀、滑坡、坍塌、泻流、融冻侵蚀等。水土流失面积为389232.10km2,占全省土地面积的85.66%。全省强度、极强度和剧烈侵蚀面积分别占侵蚀总面积的24.71%,12.41%,14.20%。水土流失的危害导致土壤剥蚀,地力下降。甘肃黄土高原平均每年流失泥沙总量为5.18×108t,每年流失表…     

陕北黄土高原降雨侵蚀力时空变化研究

陕北地区是典型的黄土高原水土流失严重区,降雨侵蚀力是表征水蚀地区降雨侵蚀潜力的复合指标。系统分析降雨侵蚀力国内外研究现状,采用陕北及其周边地区27站日降雨资料及降雨侵蚀力简易计算方法,分析陕北地区降雨侵蚀力季节差异、年际变化,绘制了陕北地区多年平均及其20世纪各年代降雨侵蚀力空间分布等值线,研究结果对进一步认知陕北地区水土流失规律、指导水土保持工作具有重要意义。     

黄土高原沟壑区小流域水土流失治理对径流的效应

本文用小流域平行对比观测法,分析了黄土高原沟壑区典型小流域水土保持对流域地表径流量及暴雨产流过程的影响,表明：（１）在黄土高原沟壑区,水土流失综合治理减少小流域产洪次数,降低了流域地表径流模数和径流系数,尤其以少雨年最显著;（２）使小流域地表径流模数的年际变率增大;（３）在洪水产理措施区土壤水分含量降低,根据生物气候、土壤及区域拦蓄水量特征,推测黄土高原沟壑区,以造林为主的水土保持措施拦蓄径流的作用难以使地表径流转化为地下径流或增加地下水。     

覆沙坡面微地形变化与侵蚀产沙的响应关系

坡面微地形的发育反映了侵蚀的强度及变化过程。为了定量研究不同覆沙厚度下坡面的微地形变化与侵蚀之间的响应,通过模拟1. 5 mm·min~(-1)雨强下的3场连续降雨试验,结合三维激光扫描仪技术,分析了坡面微地形与土壤侵蚀的空间变化特征,较好地拟合了微地形变幅与侵蚀量之间的关系。结果表明:坡面平均含沙量随着降雨场次的增加而减小。覆沙坡面主要产沙区的长度是黄土坡面的3倍左右,且坡段侵蚀量的峰值多分布在坡面4～6 m的位置,而黄土坡面侵蚀峰值分布在3～4 m的位置。随着降雨场次的增加,黄土坡面微地形因子显著增大(P 0. 05),覆沙坡面微地形因子总体呈增大趋势,但并不显著(P 0. 05)。与黄土坡面和覆沙坡面的侵蚀响应最强烈的微地形因子分别为地表切割深度和地表粗糙度,黄土坡面微地形变幅与侵蚀量的响应关系较强于覆沙坡面,覆沙坡面应寻找其他敏感的指标对方程进行优化。该研究为揭示风水复合侵蚀地区的侵蚀机理提供一定参考。     

基于地形校正的山区积雪深度反演算法

积雪深度是天气和水文模型运行的必要参数。利用微波遥感可以反演不同尺度的地表积雪深度参数,为全球或区域尺度气候模型与水循环提供有效积雪参数。现有积雪深度微波遥感反演算法未综合考虑地形因子对反演结果的影响。微波辐射计观测的地表信号会受到地形的影响,导致能量在地表重新得到分配,这不仅引起传感器本身的观测误差,而且改变了地表的微波散射和辐射,使得水热能量在地表重新分配,从而也影响着地表关键参数的反演精度。为了提高山区积雪深度的反演精度,分析了坡度、坡向等地形因子对积雪深度反演的影响,在利用微波遥感反演积雪深度时加入地形坡度和坡向校正,构建基于地形效应的微波辐射模型,提出基于地形校正的山区积雪深度反演算法。实验结果显示,地形校正前,积雪深度反演的RMSE=10.41,地形校正后,积雪深度反演的RMSE=7.22,积雪深度反演精度得到了一定的提高。     

黄土高原地区自然环境演变区域分异与综合治理初步研究

黄土高原及其毗邻地区自然环境演变及区域分异的研究,涉及到若干虽经长期争论,至今并未得到解决的基础理论问题。然而,它们却是治理黄土高原严重水土流失的重要基础。本文就全新世以来的植被变迁、历史时期农牧业发展历程、黄土高原空间范围、干湿状况和雨养农业、现代自然环境的区域分异与综合治理等问题阐述了基本观点。认为,全新世中晚期以来,多数地方就是森林和草原相嵌构成的自然景观;全新世晚期以来,植被的破坏加剧;历史时期农牧业区域曾经历频繁更迭;现在的种种环境问题,自清朝以来已全部明朗化;黄土高原的空间范围与地质上的黄土沉积稳定带大体相符,面积近36万平方公里;水土流失的治理和农业生产均应以自然区域分异为纲。     

试论水土流失的人为侵蚀及其防治对策

剖析水土流失加剧的成因，不能不涉及人为侵蚀这个根本问题，人为侵蚀为主要是由经济问题引起的，它的实质是人口需求侵蚀，经济增长侵蚀，有效运用经济手段是协调人类需求，经济增长与水寺保持矛盾的一条重要途径。文章从经济角度提出了防治人为侵蚀的１０条对策。     

黄土高原人工草地的土壤水分动态及水土保持效益研究

通过９年观测，黄土高原人工草地土壤水分的季节性变化可划分为三个阶段，在此基础上模拟不同人工草地土壤水分的变化规律；随着牧草生育期的延长至第９年，人工草地土壤水分恢复程度逐渐减弱；沙打旺生存能力极强，能够高效地利用深层土壤贮水；用数学模型可以模拟不同人工草地的水土流失，将植被因子引入水土流失方程，可以定量描述对水土流失的影响；反映植被、土壤等因子与水土流失关系的复合因子Ａ￣１值，基本上代表不同人工草地水土流失状况。     

黄土高原可持续农业开发模式研究——以陕西黄土高原区为例

本文阐述了中国持续农业发展的基本特征和目标，分析了黄土高原水土流失、南养农业、自然灾害、经济贫困等自然和经济发展特征，提出了黄土高原持续农业开发的原则、基本思路、发展目标、持续农业发展３种模式和主要对策措施。     

兰州市水土流失态势及其新世纪调控对策

在系统分析研究历史文献、遥感信息和实地考察资料的基础上，综述了兰州市区水土流失现状及发展趋势；对土壤侵蚀界面支系统、侵蚀物源支系统、侵蚀动力支系统等水土流失环境系统结构组成及内部结构协调功能进行了综合分析研究，认为：该系统内部许多单因子自调节功能已遭到严重破坏，其中部分因子已超过环境自调节阈临界水平，恶性灾害将会与日俱增，并针对环境系统内部结构协调关系的恶化趋势，提出了综合而切合实际的调控对策。     

黄土高原土壤水分与植被生产力的关系

土壤水分生态条件的恶化愈来愈成为黄土高原植被建设和生态环境建设的限制因素，我们在对黄土高原土壤水分生态因素分析的基础上，探讨了黄土高原土壤水分的季节性变化、土壤剖面水分变化、区域水分变异规律，分析了土壤水分与植被生产力间的相互关系，并提出了改善黄土高原土壤水分生态环境、提高植被生产力的调控技术。     

陕北黄土高原社会经济发展中的问题及对策分析—以子长县为例

陕北黄土高原是陕西省经济较落后的地区,也是黄土高原水土流失最严重的地区之一。对于这个地区的整治、开发具有重要的意义。本文从以黄土高原考察研究重点县之一的子长县为例,对这个地区当前社会经济发展中的问题进行了分析,并以此为基础提出其初步发展对策。     

Soil hydraulic conductivity as affected by vegetation restoration age on the Loess Plateau,China

The Loess Plateau of China has experienced extensive vegetation restoration in the past several decades,which leads to great changes in soil properties such as soil bulk,porosity,and organic matter with the vegetation restoration age.And these soil properties have great effect on the soil infiltration and soil hydraulic conductivity.However,the potential changes in soil hydraulic conductivity caused by vegetation restoration age have not been well understood.This study was conducted to investigate the changes in soil hydraulic conductivity under five grasslands with different vegetation restoration ages(3,10,18,28 and 37 years)compared to a slope farmland,and further to identify the factors responsible for these changes on the Loess Plateau of China.At each site,accumulative infiltration amount and soil hydraulic conductivity were determined using a disc permeameter with a water supply pressure of –20 mm.Soil properties were measured for analyzing their potential factors influencing soil hydraulic conductivity.The results showed that the soil bulk had no significant changes over the initial 20 years of restoration(P0.05);the total porosity,capillary porosity and field capacity decreased significantly in the grass land with 28 and 37 restoration ages compared to the slope farmland;accumulative infiltration amount and soil hydraulic conductivity were significantly enhanced after 18 years of vegetation restoration.However,accumulative infiltration amount and soil hydraulic conductivity fluctuated over the initial 10 years of restoration.The increase in soil hydraulic conductivity with vegetation restoration was closely related to the changes in soil texture and structure.Soil sand and clay contents were the most influential factors on soil hydraulic conductivity,followed by bulk density,soil porosity,root density and crust thickness.The Pearson correlation coefficients indicated that the soil hydraulic conductivity was affected by multiply factors.These results are helpful to understand the changes in hydrological and erosion processes response to vegetation succession on the Loess Plateau.     

试论黄土高原县域经济开发的突破口问题

本文在对黄土高原治理方向和开发途径进行探讨的基础上,论述了黄土高原县域经济开发中作为突破口的“投资少、见效快”项目对于实现县域综合发展目标的重要意义。并以若干典型县为实例,具体分析了这类产业项目选择中应注意的一些问题。     

黄土高原路面雨水的农业资源化利用技术

通过对黄土高原水资源现状分析,提出了采用消能淤泥坑,通过直接、间接将路面雨水引入农田"土壤水库"或时空可调节的自压式集流水窖等贮水设备中,并采用一定的耕作农艺措施将路面雨水利用到农田中的方法和技术.多年的甘肃定西试验和实践表明,使用这种技术不仅提高了天然降水的利用效率,而且简单易行,是黄土高原地区农业雨水资源利用的一个有效途径,同时该技术具有防止水土流失和改善旱区农业生态环境的效应.     

Effect of Pisha sandstone on water infiltration of different soils on the Chinese Loess Plateau

The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density(BD), porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity(Ks). The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1:3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.     

Effect of Pisha sandstone on water infiltration in different soils on the Chinese Loess Plateau

The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1:1, 1:2, 1:3, 1:4, and 1:5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density (BD), porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity (Ks). The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1:3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.     

Soil surface roughness change and its effect on runoff and erosion on the Loess Plateau of China

As an important parameter in the soil erosion model, soil surface roughness（SSR） is used to quantitatively describe the micro-relief on agricultural land. SSR has been extensively studied both experimentally and theoretically; however, no studies have focused on understanding SSR on the Loess Plateau of China. This study investigated changes in SSR for three different tillage practices on the Loess Plateau of China and the effects of SSR on runoff and erosion yield during simulated rainfall. The tillage practices used were zero tillage（ZT）, shallow hoeing（SH） and contour ploughing（CP）. Two rainfall intensities were applied, and three stages of water erosion processes（splash erosion（I）, sheet erosion（II） and rill erosion（III）） were analyzed for each rainfall intensity. The chain method was used to measure changes in SSR both initially and after each stage of rainfall. A splash board was used to measure the splash erosion at stage I. Runoff and sediment data were collected continuously at 2-min intervals during rainfall erosion stages II and III. We found that SSR of the tilled surfaces ranged from 1.0% to 21.9% under the three tillage practices, and the order of the initial SSR for the three treatments was ZT〈SH〈CP. For the ZT treatment, SSR increased slightly from stage I to III, whereas for the SH and CP treatments, SSR decreased by 44.5% and 61.5% after the three water erosion stages, respectively, and the greatest reduction in SSR occurred in stage I. Regression analysis showed that the changes in SSR with increasing cumulative rainfall could be described by a power function（R2〉0.49） for the ZT, SH and CP treatments. The runoff initiation time was longer in the SH and CP treatments than in the ZT treatment. There were no significant differences in the total runoff yields among the ZT, SH and CP treatments. Sediment loss was significantly smaller（P〈0.05） in the SH and CP treatments than in the ZT treatment.     

黄土高原苹果园不同集水阻渗技术调控下土壤水分、矿质氮含量变化

以黄土高原苹果园果树为研究对象,分析不同集水阻渗技术调控下土壤水分、矿质氮含量的变化,探索适宜旱区果园可持续发展的防渗聚水技术。结果表明:起垄覆膜处理(Ⅰ)、防渗层处理(Ⅱ)和起垄覆膜加防渗层处理(Ⅲ)均能增加0～300 cm土层土壤含水量,减少土壤硝态氮含量。处理Ⅲ总体效果最好,能够增加9.60%土壤含水量,减少57.15%土壤硝态氮含量;处理Ⅰ使0～200 cm土层土壤含水量均匀增加7.73%,硝态氮含量均匀减少60.08%;处理Ⅱ能够增加0～40 cm表层土壤7.37%的土壤含水量,减少40～200 cm中层土壤74.38%的硝态氮含量。研究表明,不同集水阻渗技术通过改变水分的时空分布、减少硝铵态氮的淋溶从而提高水肥利用效率,其中起垄覆膜加防渗层处理结合了起垄覆膜与人工防渗层两种技术的优点,能够有效调控土壤水分运动,减少硝态氮深层淋溶,是黄土高原改善土壤水肥状况、增加果园产量、使果业可持续发展的可行技术措施。