Comparative Study of Guizhou Sloping Land Soil and Water Conservation Effect of the Three Cropping Patterns

Surface cover degree,monthly variation of topsoil water content,loss of soil and nutrient in alfalfa-corn intercropping,strip rotation cropping and corn monoculture were studied in this paper. Then soil and water conservation effect of these planting modes were compared. Results showed that surface cover degree was high during the all rainy season in both alfalfa-corn intercropping and strip rotation cropping mode, with slope field covered by vegetation all the year round. Roots of alfalfa grew well,which not only improved the root biomass in 0-20cm layer,enhanced the capacity of the infiltration of rainwater to soil,protected biodiversity,but also reduced surface off and soil erosion of 39. 3% and 59. 3% . Strip rotation cropping could also reduce surface off and soil erosion of 10. 4% and 21. 3% . Both alfalfa-corn intercropping and strip rotation cropping increased soil moisture in rainy season and before rainy season,whilst reduced loss of organic matter (caused by soil erosion) of 29. 9%-52. 4% ,total N of 26. 7%-54. 9% ,total K of 27. 3%-70. 9% ,slow available K of 21. 4%-58. 9% ,increased corn production of 33. 0%-35. 9% . Moreover,there was 13664kg/hm 2 in alfalfa-corn intercropping,which was 4. 1 times higher than common mode. There was 12492 kg/hm 2 in strip rotation cropping which was 2. 7 times higher than common mode.

Effects of Terracing and Agroforestry on Soil and Water Loss in Hilly Areas of the Sichuan Basin, China

Soil erosion in hilly areas of the Sichuan Basin is a serious concern over sustainable crop production and sound ecosystem. A 3-year experiment was conducted using the method of runoff plots to examine the effects of terracing and agroforestry in farmland systems on soil and water conservation of slope fields in the hilly areas in Jianyang County, Sichuan Province, Southwestern China. A power function (Y = aXb) can statistically describe the relationship between water runoff (Y) and rainfall (X). The regression equation for the treatment of sloping terraces with crops (Plot 2) is remarkably different from that for the treatment of sloping terraces with grasses and trees (Plot 1) and the conventional up- and down-slope crop system (Plot 3) regarding equation coefficients, while regression equations are similar between Plot 1 and Plot 3. Water runoff amount and runoff coefficient of slope fields increased by 21.5～41.0 % and 27.5～69.7 % respectively, compared to those of sloping terraces, suggesting that terracing notably reduced the water runoff in the field. In the case of sloping terraces, lower amount of water runoff was observed on sloping terraces with crops than on sloping terraces with grasses and trees. Sediment yields on the slope fields in the normal year of rainfall distribution were notably higher (34.41～331.67 % and 37.06～403.44 % for Plot 1 and Plot 2, respectively) than those on sloping terraces, implying that terracing also plays a significant role in the reduction in soil erosion. It is suggested that terracing with crops is significantly effective for soil and water conservation in cultivatedfarmland, while the conventional practice of up- and down- slope cultivation creates high rates of water runoff and soil sediment transport. Terracing with grasses and fruit trees shows a less reduction in water runoff than terracing with crops, which was observed in the 3-year experiments.

Features of Runoff and Sediment Yield of Different Shrub-Grass Combination Modes for Highway Side Slope in Hilly Areas of Central Sichuan Province

[Objective] Indigenous plants with favorable water and soil conservation effects were screened for the shrub planting.[Method] Suining-Ziyang-Meishan Highway in the hilly areas of central Sichuan Province was taken for example,through sorting out plant species investigated in the route planning,3 indigenous shrub species(Neosinocalamus affinis,Vitex negundo and Coriaria nepalensis) and 3 indigenous herbaceous species(Setaria viridis,Miscanthus floridulus,Artemisia argyi) were selected.Rainfall simulation experiment was adopted to compare runoff and sediment yields of different combination modes and ratios under constant rainfall intensity(20 mm/min).[Result] Different combination modes under constant rainfall intensity all showed better water and soil conservation effects than that of control group did.For example,runoff appeared 1'-4'05"later,sediment yield reduced by 6.56-33.86 g respectively.Among all combination modes,runoff and sediment yield showed great difference after 20 min of constant rainfall,V.negundo+S.viridis had the lowest runoff(1,700 ml) and sediment yield(60.71 g);C nepalensis+A. argyi had the highest runoff(1,920 ml) and sediment yield(84.02 g).[Conclusion] Given the same planting conditions such as side slope and seeding quantity,and also the same planting techniques,in the hilly areas of central Sichuan Province,the combination of V.negundo and S.viridis can greatly improve the water and soil conservation capacity of highway.

Water Availability for Winter Wheat Affected by Summer Fallow Tillage Practices in Slope Dryland

The tillage experiments for winter wheat were conducted on the slope farmland in Luoyang, Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods including reduced tillage(RT), no-till(NT), 2 crops/year(2C), subsoiling(SS), and conventional tillage(CT)were compared to determine the effects of tillage methods on soil water conservation, water availability, and wheat yields in a search for better farming systems in the areas. The NT and SS showed good effects on water conservation. The soil water storage increased 12 - 33 mm with NT and 9-24 mm with SS at the end of summer fallow periods. The soil evaporation with NT and SS decreased 7-8 mm and 34 - 36 mm during the fallow periods of 1999 and 2001, respectively. Evapotranspiration(ET)with NT and SS increased about 47 mm during wheat growth periods of 2000 to 2001. Treatment RT and 2C had low water storage and high water losses during the fallow periods. The winter wheat yields with conservation tillage practices were improved in the 2nd year, increased by 3, 5 and 8% with RT, NT and SS, respectively, compared with CT. The highest wheat yields were obtained with subsoiling, and the maximum economic benefits from no-till. All conservation tillage practices provided great benefits to saving energy and labors, reducing operation inputs, and increasing economic returns. No-till and subsoiling have shown promise in increasing water storage, reducing water loss, enhancing water availability, and saving energy, as well as increasing wheat yield.

Soil Bunds Effect on Soil Properties under Different Topographies of the Southwest Ethiopia

Soil erosion is a major environmental problem affecting development endeavor.Physical soil and water conservation(SWC)measures such as soil bunds are implemented to mitigate soil erosion.However,information on the effects of soil bunds on soil fertility is limited.This study was aimed to evaluate soil quality in fields with soil bunds and with no soil bunds in steep,middle and lower sloping cultivated lands as well as spatial variation of soil properties in between bunds in southwest Ethiopia.About 7-15 years old bunds and nearby cultivated fields lacking bunds were assessed.From 0 cm-20 cm soil depth,a 36 soil samples were collected.Soil texture,soil organic carbon(SOC),total nitrogen(N_(tot))and exchangeable potassium(K_(exch))were analyzed.Soil bunds showed significantly(p<0.0.5)greater clay but less sand than adjacent no-bund fields.In steep,middle,and lower slopes,concentrations of SOC and Kexch were greater in fields with soil bunds than without.Lower slope fields showed greater clay,SOC and nutrients than steep slopes.In between soil bunds,soil was more fertile at above bunds than below the bunds.In Fanta watershed,soil bunds are vital conservation measure to retain soil fertility on cultivated mountainous area.

三维土工网边坡防护水土保持能力研究

路基边坡防护工程可减轻降雨对坡面土体的侵蚀作用,为深入研究坡面防护材料水土保持能力的定量表征方法,通过室内人工降雨边坡侵蚀模型试验,分析不同降雨强度和不同三维土工网防护下路基边坡的降雨侵蚀规律,提出三维土工网水土保持能力的试验测定方法及相关系数计算公式。研究结果表明:三维土工网防护边坡泥沙流失干质量明显小于相同条件下不设防边坡泥沙流失干质量,土工网防护在减少边坡侵蚀量的同时,有利于边坡侵蚀进程的快速稳定,但土工网的水土保持能力随雨强增大急剧下降。泥沙流失速度随着降雨的持续而逐渐减小,后期趋于收敛稳定,侵蚀历程采用指数函数拟合具有较好的相关性。建议设防边坡的试验降雨时间不少于70 min,不设防的边坡试验降雨时间不小于100 min。水土保持能力系数随雨强的增大呈对数函数关系减小,雨强超过100 mm/h时水土保持能力系数实测值与对数函数拟合值差异较大,建议在测定材料水土保持能力系数时雨强取20~100 mm/h,可取50 mm/h作为标准试验雨强。泡面类三维土工网水土保持能力显著优于普通三维土工网,而双泡面的三维土工网优于单泡面三维土工网。试验条件下凹凸泡面三维土工网的水土保持能力系数主要分布在1.71~3.03,建议50 mm/h雨强三维土工网水土保持能力系数不应小于1.5。

南方崩岗调查内容与方法探讨

崩岗是我国南方水土流失的一种特殊类型,广泛分布于南方红壤区,是该区域严重的生态问题之一。第一次崩岗调查距今已近20年,相关情况已发生巨大变化。崩岗现状不清直接影响了行政管理部门对崩岗防治相关工作的规划和决策,因此急需开展新一轮崩岗调查。新时代水土保持高质量发展为崩岗调查提供了机遇,差别化分类防治和分步实施对崩岗调查提出了更高要求,现代信息技术为崩岗调查提供了新方法,以服务崩岗风险评估和防治规划为导向,在充分利用第一次崩岗调查成果基础上,补充崩岗发育的小山体调查,将典型调查改为全面普查,系统探讨崩岗调查对象与范围、调查内容、调查程序与方法,以期为行政管理部门和技术单位启动新一轮崩岗调查工作提供参考。

不同作物种植模式下坡耕地产流产沙的模拟研究

产流产沙是坡耕地水土流失的主要形式,为探讨不同种植模式对坡耕地产流产沙的影响,采用室内人工模拟降雨试验方法,在同一坡度、3种雨强下对坡耕地7种种植模式进行模拟试验。结果表明:1)不同种植模式下坡面产流量随雨强增大而增大,初始产流时间随雨强增大而缩短。坡面产流量趋势为先逐渐增大,之后(10 min左右)逐渐趋于稳定。C单种模式减流效果最差;A-B-C套种模式减流效果最好;低矮作物单种及参与的套种模式能更好促进降雨入渗。2)不同种植模式下坡面产沙量与雨强呈正相关,低矮作物参与的种植模式径流含沙量变化幅度较小,中、高单种或套种模式径流含沙量变化复杂。小、中雨强下,A-B-C套种模式减沙效果最好;大雨强下,A-B套种模式减沙效果最好。低矮作物参与的种植模式减沙效果优于中、高作物单种其套种模式。3)不同种植模式下产流量和雨强均呈极显著正相关。B、C单种模式与A-B-C套种模式产沙量与雨强有相关关系,其余模式与雨强的相关性不显著。综上,低矮作物单种及低矮作物参与的套种模式能有效减流、保土,因此坡耕地在进行农作物种植时应考虑增加低矮作物参与种植,避免造成大量水土流失。

岷江干旱河谷土石混合边坡不同种植处理下乡土植被的生态效益

岷江干旱河谷生态环境脆弱,植被恢复困难,大规模的公路建设极易对当地生态环境造成破坏。筛选适宜的植被恢复措施对干旱地区道路边坡的乡土植被恢复重建和生态功能提升尤为重要。以岷江干旱河谷极端退化的土石混合的道路边坡为案例,选取乡土灌木和草本植物构建植物群落,进行裸地播种、播种后覆盖纤维毯和添加腐殖土后播种并地表覆盖纤维毯3种不同的种植处理,揭示了不同处理下群落结构、土壤改良以及水土保持效益的差异。发现,乡土灌草群落是干旱河谷适宜的道路边坡植被恢复模式,种植后第3年群落特征趋近于岷江干旱河谷区自然生态系统的多年生灌草植被。纤维毯覆盖+覆土处理在促进植物生长和群落构建,水土流失防治上效果最好,群落总盖度为74%,群落总生物量为506.35 g/m^(2);生长季内,与自然恢复相比小区径流量减少了87.8%,泥沙流失量降低了92.1%。土壤改良效应在3种处理之间差异不明显,但是与自然恢复样地相比,各处理均提升了边坡0-20 cm土层土壤养分。不同种植处理下植物群落结构差异是影响干旱河谷土石混合的道路边坡水土流失的关键因子。

黑土区坡耕地水土保持耕作措施对土壤理化性状的影响

为探寻黑土区坡耕地不同水土保持耕作措施对土壤理化性状的影响机理,开展了田间小区试验。设置横坡耕作(TP)、垄向区田(RF)、深松(SF)、横坡耕作+垄向区田(TP-R)、横坡耕作+深松(TP-S)、垄向区田+深松(RF-S)3种水土保持耕作措施及3种组合耕作措施,并以常规顺坡耕作(CK)为对照,分析了土壤孔隙度、土壤机械组成、水稳性土壤团聚体稳定性、土壤养分含量等指标,并采用TOPSIS模型对不同水土保持耕作措施进行了综合评价,筛选了土壤稳定性强且蓄水保肥效果良好的水土保持耕作措施。结果表明:在玉米的全生育期内,深松、垄向区田、横坡耕作均能提高土壤体积含水率。TP-S处理体积含水率最大,0~40 cm土层平均体积含水率较CK处理增加29.47%;RF-S处理平均孔隙度最大,TP-S处理次之,平均孔隙度较CK处理分别增大10.68%、9.25%;TP-S处理能够显著提高土壤稳定性,其中平均质量直径(MWD)、几何平均直径(GMD)和大团聚体含量(R0.25)较CK处理分别增加12.30%、19.57%、13.97%;TP-S处理能够改善土壤机械组成,TP-S处理粗砂粒、粉粒、黏粒含量较CK处理增加15.40%、26.89%、1.90%,细砂粒含量较CK处理降低31.56%;TP-S处理IN(无机态氮)、AP(有效磷)、AK(速效钾)含量最高,较CK处理IN、AP、AK含量分别增加42.81%~55.32%、39.69%~40.68%、20.41%~25.45%。由TOPSIS模型综合评价结果可知,TP-S处理贴合度最高,土壤结构更稳定,且蓄水保肥效果更好,为适宜该地区的水土保持耕作措施。

两种草本植物对红黏土边坡的固土护坡效应

[目的]探讨两种草本植物对红黏土边坡的固土护坡效应,为该类型边坡、河道、大坝的生态治理提供科学参考。[方法]以红黏土边坡为研究对象,选取狗牙根和香根草作为护坡植物,通过种植试验、根系拉伸试验、直剪试验、室内模拟冲刷试验,探讨两种草本植物的护坡效应。[结果]①种植150 d内,两种草本植物均稳定生长,根系抗拉强度持续增加;生长30~150 d,狗牙根的最大抗拉力从0.84 N增至8.59 N,香根草的最大抗拉力从4.78 N增至89.89 N。②生长120 d时,对比无根土,狗牙根根土复合体的黏聚力提升91.1%,内摩擦角提升12.45%;香根草根土复合体的黏聚力提升107.47%,内摩擦角提升12.74%。③生长150 d时,对比裸坡,狗牙根坡的径流速率降低45.02%~54.15%,产沙速率降低58.3%~93.85%,60 min累计产沙量降低81.02%;香根草坡的径流速率降低35.46%~46.48%,产沙速率降低46.8%~89.44%,60 min累计产沙量降低74.61%。[结论]两种草本植物对红黏土边坡都具有良好的固土护坡效应,香根草对土体抗剪强度的增益效果更明显,狗牙根的水土保持效果更显著。

石漠化边坡及其植被板槽的地下渗漏一体化综合观测技术及应用模拟

【目的】表土贫瘠的石漠化边坡的地表和地下水土流失严重,限制了该地区的植被恢复,其水土保持生态防护是目前绿色公路建设的热点问题。【方法】结合广西贺巴高速来都段石漠化边坡应用梯级植被板槽进行水土保持的工程需求,研发了石漠化边坡地下渗漏的一体化综合观测技术,并利用数值分析软件,分别对该石漠化边坡及其植被板槽水土流失一体化综合观测的概化模型,进行应用性的数值试验模拟观测和分析。【结果】数值试验结果表明:石漠化边坡在仅覆盖一层薄土层时,总地下渗漏量达到65%以上,随着岩溶裂隙率和裂隙倾角的增加,基岩裂隙渗漏量占比增加,表层岩溶带渗漏量占比减小;在石漠化边坡上设置集约化填土的植被板槽措施后,在不考虑板槽底的防渗漏材料时,总地下渗漏量占比变成40%左右,与仅覆盖一层薄土的石漠化边坡相比地下渗漏占比降低25%以上。石漠化边坡上植被板槽的蓄水效率随植被覆盖度的增加而增加;坡度的增加会造成裸露边坡的地下渗漏量增加,因此必须加强石漠化边坡集雨面功能的建设和坡面降雨径流收集。【结论】研究成果可为石漠化边坡植被板槽水土保持生态防护措施的现场研究和工程应用提供理论依据。

基于环境模拟的尾矿边坡水土保持植物筛选研究

为筛选尾矿边坡水土保持优良物种,选取江西5种乡土植物(芒萁、狗牙根、马唐、百喜草、三裂叶薯)作为研究对象,对其在模拟边坡种植后土壤水分物理性质及地表径流和土壤侵蚀情况开展研究,并采用熵权TOPSIS法对5种植物进行水土保持功能评价。结果表明:(1)芒萁、狗牙根、马唐、百喜草、三裂叶薯种植后边坡的土壤水分物理性质得到显著改善,土壤容重范围为1.26~1.40 g·cm^(-3),土壤总孔隙度在41.26%~48.11%之间,土壤含水量在8.2%~27.6%之间,土壤水分物理性质改善顺序为芒萁>狗牙根>马唐>百喜草>三裂叶薯;(2)芒萁、狗牙根、马唐、百喜草、三裂叶薯种植后相对于裸地,径流输出量和土壤侵蚀量显著减少,平均减少了46.43%和66.89%,大小顺序皆为芒萁>狗牙根>三裂叶薯>马唐>百喜草;(3)采用TOPSIS法对5种乡土植物水土保持功能的评价结果从大到小依次为芒萁>狗牙根>马唐>三裂叶薯>百喜草。综上,芒萁、狗牙根保持水土功能较强,在进行尾矿生态修复时可优先搭配芒萁、狗牙根,实现尾矿边坡水土流失防治和土壤改良模式优化。

黄土丘陵沟壑区降雨特征对不同土地利用类型坡面产流产沙的影响

【目的】探究黄土丘陵沟壑区降雨特征及其对不同土地利用类型坡面产流产沙的影响。【方法】2019-2021年,以内蒙古达拉特旗合同沟小流域为研究区,设置5个不同土地利用类型(裸地、天然草地、灌木林地、农地、乔木林地)径流小区,监测研究区的降雨特征指标(降雨量、降雨历时、30 min最大降雨强度(I 30)、平均降雨强度、降雨侵蚀力),利用K-均值聚类法,以研究区的降雨特征指标为变量,对合同沟小流域的侵蚀性降雨进行分类;计算不同土地利用类型径流小区的径流深和土壤流失量,分析不同土地利用类型和不同降雨类型对坡面产流产沙的影响,最后分析了合同沟小流域降雨特征与不同土地利用类型坡面总径流深和总土壤流失量的相关性。【结果】(1)2019-2021年,合同沟小流域降雨分布不均匀,共发生降雨128次,其中侵蚀性降雨51次,侵蚀性降雨量占总降雨量的80.2%,且侵蚀性降雨主要集中在6-8月。(2)将侵蚀性降雨分为3类:Ⅰ类降雨(大雨量、长历时、高强度);Ⅱ类降雨(中雨量、中历时、中强度)和Ⅲ类降雨(小雨量、短历时、低强度)。与Ⅱ类降雨和Ⅲ类降雨相比,Ⅰ类降雨发生的频次较低,但其平均降雨侵蚀力较强;在同一土地利用类型下,Ⅰ类降雨造成的坡面径流深和土壤流失量均明显较大。(3)2019-2021年,不同土地利用类型径流小区坡面产流产沙特征差异明显,总径流深和总土壤流失量由大到小依次为裸地>农地>天然草地>灌木林地>乔木林地。(4)各降雨特征指标与不同土地利用类型的坡面总径流深和总土壤流失量均呈正相关关系,其中降雨量、降雨强度和I_(30)的影响较大。【结论】在黄土丘陵沟壑区,降雨量、降雨强度和I_(30)是影响坡面产流产沙的最主要指标,天然草地、乔木林地、灌木林地的减流减沙效益较好,可知农地退耕还林还草工程是减少土壤侵蚀的有效措施之一。

汾西县马沟河流域边坡生态修复探讨

城市飞速发展,各种基础工程正加快建设的脚步,可环境问题也随之而来,各种项目的施工导致土地上出现了许多裸露的斜坡。因此,边坡生态修复成为了研究和实践的热点。以汾西县马沟河流域为例,从工程地质条件、地质灾害分布及类型、地质灾害诱因及防治、边坡治理设计几个方面探讨,得出边坡治理首先应注重安全,并针对不同的场地情况做出不同的处理措施,其次则是考虑治理以及恢复生态的措施以便恢复生态群落,保障水土不会流失的结论。以期以汾西县马沟河流域边坡的处理方式为类似边坡生态修复工程提供参考性意见,探索出较为科学的解决方法与绿色发展路径。

穿梭山体的线型项目水土保持方案汇水分析特点难点及方法

本文以沙荷路—盐排高速立交工程(二期)项目为例,对穿梭山体的线型项目的原始地形、工程施工建设新形成的边坡改变地形致使汇水方向发生改变进行了分析,根据排水出口承担的汇水面积对截排水沟规格及沉沙池缓冲沉淀效果进行校核及补充设计,以发挥水土保持效用,使施工期水土流失降至容许范围内。

南方红壤坡地不同耕作措施的水土保持效应

为解决南方红壤地区坡耕地水土流失问题,采用野外标准径流小区试验方法对南方红壤坡地常见的顺坡间作、横坡间作、果园清耕3种不同耕作方式下5a时间水土保持蓄水保土效应进行了研究。结果表明,与对照小区相比,各试验小区减流率优劣次序为:横坡间作小区(75.33%)>顺坡间作小区(59.56%)>果园清耕小区(21.73%),减沙效应优劣次序为横坡间作(80.57%)>顺坡间作(65.11%)>果园清耕(38.08%),且4-9月的径流量占到全年径流量的85%以上,流失泥沙量占全年流失泥沙量的90%以上。因此,套种作物增加果园覆盖是防治果园水土流失的有效措施,且横坡间作优于顺坡间作。

喀斯特山区退耕还林(草)保持水土生态效益研究

通过3年定位、半定位观测,对贵州山区退耕还林(草)地进行采样并采用无界径流小区法收集地表径流样品,探讨贵州山区退耕还林(草)措施对贵州山区土壤养分流失以及水土保持效益的影响。试验结果表明:退耕还林(草)后旱坡地地表径流中泥沙含量降低,土壤养分流失减少,土壤容重降低,土壤理化性质改善。尤其是旱坡陡耕地,可以明显降低土壤侵蚀。

川中丘陵坡耕地水土保持与农业生产的发展

总结了作者近 10多年来在水土保持和作物栽培中所做的研究工作 ,在分析研究川中丘陵坡耕地水土流失状况基础上 ,提出了一套既有益于水土保持 ,又能提高作物产量 ,提高农户经济收益的工程措施和农耕措施 ,对今后如何协调川中丘陵坡耕地水土保持与农业生产的发展有重要指导意义。

红壤坡地不同类型梯田的水土保持效应

应用江西省水土保持生态科技园红壤坡地不同类型梯田小区的观测资料,对不同类型梯田的水土保持效应和柑橘生长情况进行分析。分析结果表明:梯壁植草能大大提高梯田的蓄水保土效益和柑橘产量。从蓄水效益来看,采取“前埂后沟+梯壁植草”方式的水平梯田与外斜式梯田相比,其蓄水效益提高81.4%;从保土效益来看,采取“前埂后沟+梯壁植草”方式的水平梯田与梯壁不植草的对照水平梯田相比,其保土效益提高98.2%;从柑橘产量来看,外斜式梯田与采取标准方式的梯田相比,其产量提高45%;不同类型梯田水土流失量与柑橘产量不一致,这表明作物产量不仅与水土流失量有关,而且与农业技术措施关系密切。