Soil and water loss in the Lancang River-Mekong River watershed (in Yunnan section, China) and its control measures

According to a lot of hydrological and environmental monitoring data, the condition of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is described. The occurrence and development of soil and water loss is analyzed. The conclusion is that: (1) generally, the situation of soil and water loss in the Lancang River Mekong River watershed (in Yunnan section, China) is light, however, soil and water loss in some regions is serious, especially in the middle reach area of the river; (2) soil and water loss in the Lancang River Mekong River (in Yunnan section, China) watershed presents developing tendency and it is mainly caused by human beings. In accordance with these results, the control measures for soil and water loss are discussed.

A policy and technical measures for controlling soil and water loss in the Loess Plateau of China

Loess Plateau is the most serious region of soil and water loss in China and the world. The sediment carried into the Yellow River amounts to 1.6 billion tons every year. This paper reviews the factors and reasons for erosion in this area, and puts forward a comprehensive controlling policy on the basis of the principles of ecology and practise of Chinese scientists for 40 years. In conformity with the policy, a number of technical measures for controlling soil and water loss are suggested.

Soil nutrient loss due to tuber crop harvesting and its environmental impact in the North China Plain

Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.

Impact of Different Contour Hedgerows on Runoff,Nutrient and Soil on Sloping Farmland in Danjiangkou Reservoir Region of China

Soil and water loss has been a major environmental problem in the Danjiangkou Reservoir Region.A study of 14°sloping farmland was performed on impact of different contour hedgerows on runoff,losses of soil and nutrients during 2008 and 2011,with five treatments and three replications.The winter wheat and summer maize were used as the test crops.Treatments consisted of four hedgerows:Amorpha(Amorpha fruticosa L.),Honeysuckle(Lonicera japonica Thunb.),Day-lily flower(Hemerocallis citrina Baroni.),and Sabaigrass(Eulaliopsis binata),and a control without hedgerow.Result showed that the runoff under the control treatment was much higher than that of hedgerows.Amorpha could reduce the runoff by 35.2%compared with the control.Soil losses in four hedgerows showed significant reduction in four years(e.g.,Amorpha:78.3%;Honeysuckle:77.1%).Nutrient losses in winter were much higher than that in summer,especially total nitrogen,total phosphorus and total potassium,even though there was an abundant precipitation in summer.Hedgerows greatly affected the soil and nutrient losses on slopping farmland compared with the control treatment,especially Amorpha treatment.The present study found that the Amorpha could be used as the hedgerow species for reducing soil and water loss in the Danjiangkou Reservoir Region.

稻蟹共生模式对稻田水分循环和养分淋失的影响

稻蟹共生种养是全面推进我国特别是东北地区乡村振兴的特色产业,但养蟹稻田和常规稻田水分循环和水土环境特征究竟有何差异尚不清楚。为定量表征稻蟹共生种养模式水分循环和水土环境特征,在辽河入海口两处大型养蟹灌区(营口灌区和大洼灌区)布设12个典型田块,以常规稻田为对照,对养蟹稻田逐日蒸腾蒸发量、逐日渗漏量、灌溉定额、水体和表层土壤养分动态、养分淋失以及水稻和螃蟹产量等进行定量研究。结果表明:稻蟹共生模式对水稻产量无显著影响,但河蟹产值的增加,使得养蟹稻田综合经济效益比常规稻田显著提高38.89%~76.49%(P<0.05)。与常规稻田相比,养蟹稻田灌溉定额和渗漏总量分别显著增加3.29%~20.93%(P<0.05)和5.66%~10.83%(P<0.05),水分生产率显著降低1.85%~9.28%(P<0.05),但单位用水综合产值显著增加33.34%~70.23%。与常规稻田相比,养蟹稻田田面水NH_(4)^(+)-N、NO_(3)^(-)-N、速效磷和速效钾含量分别显著降低19.99%~37.24%、35.25%~56.22%、18.69%~20.30%和8.12%~9.36%(P<0.05),减轻了地表径流养分面源污染潜在风险。与常规稻田相比,养蟹稻田表层土壤NH_(4)^(+)-N、NO_(3)^(-)-N、速效磷和速效钾含量显著提高60.00%~83.88%、18.21%~44.97%、28.34%~54.56%和10.47%~21.24%(P<0.05),提升稻田土壤肥力。与常规稻田相比,养蟹稻田NH_(4)^(+)-N、NO_(3)^(-)-N、速效磷和速效钾淋溶损失量分别显著增加20.60%~25.20%、26.24%~44.75%、14.15%~18.83%和4.31%~16.94%(P<0.05),促进养分向深层剖面(20~100 cm)转移。本研究揭示了稻蟹共生系统具有提高单位用水综合产值、降低径流污染风险、提升地力和增加稻田综合经济效益等巨大潜力,但其促进稻田养分淋失的问题不容忽视。本研究可为养蟹灌区绿色可持续发展和农民增收致富提供理论依据和技术支撑。

AN APPROACH TO THE ECOAGRICULTURAL CONSTRUCTION IN BAICHA VILLAGE OF PENGYANG COUNTY,NINGXIA

Agricultural production activities are organic combinations between the courses of nat-ural reproduction and economic one. Natural reproduction course is the material base forthe agro-ecological and economic system uniformly operating. So the development ofagro-production has closely concerned with the ecological circumstances. The serious wat-

生物炭施加垄沟集雨种植对水土流失及紫花苜蓿草产量的影响

为缓解我国黄土高原区干旱胁迫和控制水土流失,本研究采用裂区设计,生物炭施加模式(生物炭施加和无生物炭施加)为主区,耕作模式(打结垄、开敞垄和平作)为副区,研究不同生物炭施加模式和耕作模式对土壤水分、径流、泥沙流失、养分流失、紫花苜蓿(Medicago sativa L.)干草产量和水分利用效率的影响。试验结果表明,在2019和2020年紫花苜蓿生育期,与平作处理相比,开敞垄和打结垄处理的径流量、泥沙、全氮、全磷、有机质流失量分别减少20.1%~37.7%和60.1%~64.7%,54%~75.5%和77.1%~87.6%,44.4%~65.5%和49.0%~81.8%,36.7%~75.3%和48.6%~87.3%,48.2%~72.9%和58.6%~85.4%,土壤贮水量、紫花苜蓿干草产量和水分利用效率分别增加39.5~52.1和31.2~60.5 mm,26.2%~31.7%和26.5%~35.2%,10.07~14.86和12.14~16.55 kg·hm^(-2)·mm^(-1)。与无生物炭施加处理相比,生物炭施加处理的径流量、泥沙、全氮、全磷和有机质流失量分别减少48%~69%,94%~125%,12%~24%,28%~46%和35%~48%,土壤贮水量、紫花苜蓿干草产量和水分利用效率分别增加42.93~26.09 mm,106%~111%和1.96~6.90 kg·hm^(-2)·mm^(-1)。本研究表明,生物炭施加打结垄沟集雨种植是该区域适宜耕作模式。

红壤丘陵区种植茶树和柑橘对土壤肥力和水土流失的影响

为探讨经济林种植对土壤肥力和水土保持的影响,以浙江省常山县红壤丘陵区种植茶树和柑橘10年后的园地为对象,并以祼地为对照,定位研究了水土流失量,采样并分析了0~10 cm土壤容重、孔隙度、速效氮磷钾和不同团聚体组分碳氮含量。结果表明:种植茶树和柑橘10年后,土壤容重显著下降(P<0.05),土壤孔隙度、田间持水量、有机碳、有效磷、速效钾和碱解氮含量显著提高(P<0.05);土壤大团聚体有机碳含量大小排序为柑橘园>茶园>祼地,土壤中团聚体、微团聚体、粉粒的有机碳、氮含量大小表现均为茶园>柑橘园>裸地,不同处理间的差异达显著水平(P<0.05);茶园土壤黏粒有机碳、氮含量显著高于柑橘园、祼地(P<0.05);与祼地相比,柑橘园和茶园年径流深显著降低了87.66%、92.25%(P<0.05),年土壤流失量显著减少了95.93%、98.78%(P<0.05)。试验区年径流深、年土壤流失量与土壤有机碳、总孔隙度、田间持水量之间具有极显著或显著负相关(P<0.01,P<0.05),与土壤容重具有显著正相关(P<0.05)。综上,茶树和柑橘种植有利于提高土壤肥力,降低水土流失,其中种植茶树的效果优于柑橘。

Phosphorus Loss from Dry Sloping Lands of Three Gorges Reservoir Area, China

Eutrophication in the Three Gorges Reservoir has become a serious issue, and phosphorus (P) is the nutrient thought to be primarily responsible although there are few studies about P loss from the mostly sloping farmlands of the area. This work investigated the amounts and forms of P loss from 9 farmlands with the slopes of 4°, 9°, and 17° in a small watershed, Wangjiagou in Fuling District, Chongqing of China. The slope of the relationship between runoff and rainfall increased with field slope; i.e., there was a significant interaction between the effects of rainfall and field slope on water export. For sediment export by surface runoff, there was no interaction between field slope and rainfall, and the intercept of the relationship between rainfall and sediment loss was significantly different for the 3 slopes. The main P loss was from sediments, regardless of slope. In the runoff water, particulate P was the largest P fraction, and its loss was greatest from the steepest land and least from the flattest. The release of total P and available P from sediments followed the same trend. The P loss during May to July in Wangjiagou was more than 60% of the annual total.

太原市滨河自行车专用道工程水土流失防治对策

根据太原市滨河自行车专用道工程概况、项目区概况以及水土流失情况,分区提出了相应的水土保持防治对策,形成有效的水土流失防治体系,工程建设造成的景观破坏、水土流失得到有效治理,恢复和美化了项目区的生态环境,让市民在高楼林立的城市环境里面也能享受到如诗如画的美景。

套种药材对红壤坡地幼龄油茶园产流产沙及氮磷流失的影响

[目的]为探究不同药材及其套种模式对红壤坡地幼龄油茶园水—土—养分流失的影响及其适用性。[方法]在中药材种植大省江西开展幼龄油茶园径流小区原位观测试验,设置套种地上收获药材艾(YA)、套种地下收获药材郁金+植物篱(YY)、传统水保措施秸秆覆盖+墒沟(YC)、清耕对照(CK),进行逐场次降雨下产流产沙、氮磷流失观测及综合效益评估。[结果](1)除清耕模式外,所有有保护性措施的模式均显著减少幼龄油茶园水-土-养分流失。与CK相比,YA、YC和YY的减流效应分别为15.22%,67.30%,64.12%,减沙效应分别为72.63%,97.19%,98.19%,总氮流失量降低幅度分别为57.86%,96.53%,95.87%,总磷流失量降低幅度分别为32.18%,98.62%,98.86%;(2)中雨、大雨和暴雨3种雨型下,套种郁金+植物篱模式均能发挥很好的水土保持和养分拦截效应,减流、减沙效应分别为45.11%~83.25%和96.08%~99.02%;减氮、减磷效应分别为83.02%~99.14%和88.38%~99.65%;而套作艾草模式则只在中雨和大雨中的养分拦截效应较好,在暴雨中的水土保持效应不明显;(3)基于TOPSIS模型,对4种模式的综合效益进行评估,排名为YY(0.48)>YC(0.29)>YA(0.23)>CK(0.02)。[结论]地下收获药材郁金+植物篱模式是试验中控制红壤坡地幼龄油茶园土壤侵蚀和养分流失最经济高效的管理措施;选用收获期与水土流失风险期错峰的药材将更好地发挥套作的生态效益,可避免幼龄油茶园产生额外的养分流失。

江西省梅江灌区工程水土流失特点及防治措施探讨

江西省梅江灌区工程是水利部对口支援赣南原中央苏区的首个重大水利工程,其建设内容点多面广,工程占地面积和挖填土石方量较大,水土流失易对周边环境造成负面影响。通过分析梅江灌区工程的水土流失特点,明确水土流失防治分区,构建水土保持措施体系,以期为同类灌区水土保持措施设计提供参考。

不同农艺措施对坡耕地水土及氮磷流失的控制

研究了丹江口水库水源涵养地小流域植物篱和4种农艺措施相结合对坡耕地水土和氮磷养分流失的拦截效果。结果表明：平衡施肥、间作和垄作对坡耕地均能不同程度地截留土壤和氮磷,其中,分别减少氮素和磷素流失31.22×10-2-40.05×10-2kg/hm2和0.03×10-2-1.04×10-2kg/hm2;植物篱小区地表径流量和土壤侵蚀量较对照分别减少了31.3%和53.9%。上述措施对小流域养分、水土流失都起到了很好的防控作用。

土壤及泥沙颗粒组成与养分流失的研究

利用自然降雨影响下的农田为试验样地,分析了降雨前后土壤颗粒组成与养分含量的变化,探讨了流失泥沙颗粒组成与养分的变化特征。结果表明,在降雨后,西瓜地与油菜地表土颗粒组成呈现粘粒与粉粒含量减少,砂粒含量相对增加的趋势;土壤养分含量都有不同程度的下降,其中水解氮与速效磷下降的幅度很大,西瓜地与油菜地水解氮降雨后降幅分别为9.67%和7.99%,速效磷的降幅分别为9.20%和8.76%;全氮养分降幅很小,西瓜地与油菜地分别为2.17%和1.54%;流失泥沙细小颗粒含量与养分含量随时间基本都呈降低的变化趋势,并且细小颗粒含量与携带流失的养分含量有显著甚至极显著的正相关性;流失泥沙具有富集粘粒和富集养分的特性,油菜地与西瓜地粘粒富集率分别为1.23和1.20,两样地全氮与速效磷的富集率都在1.3以上,而全磷和水解氮富集率基本处在1.1-1.3之间。

黄土高原南部土壤养分流失规律

本文以定位试验，野外调查和室内分析的方法研究了黄土高原南部坡耕地土壤养分流失机理、数量及时空变化规律。结果表明，泥沙流失是养分流失的主要方式，养分流失总量随地面坡度增大呈幂函数增加，土壤养分衰减氮素较磷素快，肥力高的土壤相对衰减快，坡度增大相对衰减慢，流失土壤的养分在坡度＜１２°时与坡度呈线性相关，在＞１２°时呈幂函数相关。土壤中锰、锌和有效硼微量元素衰减不明显。

紫色土坡地不同种植模式下水土和养分流失动态特征

以径流小区定位监测为基础,研究了紫色土坡地不同种植模式对水、土及养分流失特征的影响。种植试验结果表明:紫花苜蓿+青蒿模式和连翘+紫苏种植模式能较好地保持水土。各小区养分流失表现为:玉米/红苕模式小区地表径流全氮和有效氮含量高于其他小区,玉米/红苕模式和连翘+紫苏模式的小区流失泥沙全氮养分富集度高于其他小区,传统农作模式玉米/红苕通过地表径流和泥沙迁移的全氮流失总量最大,可能造成土壤耕作层肥力下降。观测期间,除由于较强的生物固氮作用,紫花苜蓿+青蒿模式增加了土壤全氮含量外,各种植模式下土壤养分均呈下降趋势,表明各小区均出现较明显的养分流失。试验证明:由于传统农作方式水土流失量最大,导致养分流失量大,对环境有较大影响。因此应注意减少传统农作方式中的地面扰动,并提高雨季地表覆盖率,从而保证农业生产的可持续发展。

表土结皮影响坡地产流产沙及养分流失的试验研究

采用人工降雨方法,模拟在无结皮、轻微结皮和严重结皮3种不同发育程度下,表土结皮对坡地产流产沙及磷钾流失过程的影响。结果表明,严重结皮具有降低产流、减少产沙的作用;坡地土壤磷钾流失过程均呈幂函数衰减趋势,无结皮坡地衰减速率最快;随着结皮不断发育,钾素流失形式以浸提态为主,逐步被溶解态所取代,磷素始终以泥沙浸提态流失占优势;与无结皮相比较,轻微结皮坡地磷和钾流失总量分别降低了20%和9%,严重结皮分别降低了52%和77%。因此,表土结皮具有减少土壤养分流失和延缓坡地土壤质量退化的作用。

辽宁省不同耕作方式对坡耕地水土及氮磷养分流失的影响效果

在天然降雨条件下,研究传统耕作、免耕、免耕秸秆覆盖、横垄4种耕作方式对坡耕地水土流失和养分流失的影响效果。结果表明:与传统耕作相比,其他3种耕作方式均能减少水土流失,产流量分别较之减少19.3%,27.1%,31.8%,泥沙量对应减少12.4%,21.5%,57.8%;各耕作小区径流中养分流失量差异显著;泥沙中全磷流失特征为T1>T3>T2>T4,其他耕作小区比传统耕作小区减少流失依次为8.6%,5.1%,12.1%;泥沙中的全氮流失特征为T1>T2>T3>T4,其他耕作小区比传统耕作小区减少流失依次为6.4%,10.3%,34.3%。坡耕地土壤侵蚀量与径流量呈显著相关。

红壤旱坡地农田生态系统养分循环和平衡

通过田间定位试验从生态系统的角度比较研究了中亚热带红壤低丘岗地几种主要旱坡地农田生态系统的水土流失、养分循环和平衡特征、土壤养分消长动态及空间分异，结果表明：水土流失是红壤旱坡地生态系统养分损失的重要途径之一，固体径流具有养分富集现象，速效养分损失以地表径流为主，水土流失养分损失量大小顺序为：有机碳＞全钾＞速效钾＞全氮＞全磷＞水解氮＞速效磷；免耕覆盖和垄作能显著减少水土流失及养分损失量；红壤旱地淋溶也是养分，尤其是氮素损失的重要途径；在养分平衡有盈余状况下，土壤养分水平是可以逐步提高的，其中，土壤速效磷、速效钾提高的速度较快，土壤全氮、有机质和全磷也有所提高，但仍处于较低水平；复合农林系统中，土壤养分存在明显的空间分异，农作物区域由于养分投入较高，土壤养分水平明显高于林木区域。

坡耕地上等高草篱的功能与效益综合分析

【目的】对等高草篱的功能与效益进行长期监测和综合分析,为北方地区坡耕地水土流失和农业面源污染防治提供理论依据和预防措施。【方法】以径流小区为基本手段、以狼尾草(Pennisetum alopecuroides(Linn.)Spreng)为代表,布设草篱处理和无草篱作为对照,其后对两种处理下土壤的物理性状、水分条件、养分水平、水土流失、养分流失以及作物产量等进行连续5年的观测,通过对比分析揭示等高草篱的各种功能,同时对其成本和作物产量效应进行综合分析。【结果】(1)狼尾草是北方地区优良的草篱候选草种,该草篱可显著改善土壤物理性质,种植5年可使土壤容重降低7.0%、稳定入渗率和总孔隙度分别增加157.1%和11.0%,并使土壤细颗粒含量(<0.01 mm)增加10.8%;(2)草篱可显著改善土壤水分条件和肥力水平,使表层土壤含水量平均增加3.5%,同时使土壤有机质及全量养分和速效养分含量明显增加,其中有机质和速效磷增幅最大,分别为12.7%和24.5%;(3)草篱年均可减少63.2%的地表径流和77.7%的土壤流失,同时减少69.4%的总氮、72.7%的硝态氮、57.3%的铵态氮、54.2%的全磷和62.3%的可溶性磷流失,具有显著的水土流失和农业面源污染防治效果;(4)草篱对其附近作物的增产作用为21.5%,但由于草篱本身需占用耕地,因此作物总产量略有降低;(5)狼尾草草篱的应用成本为2 701元/公顷,与坡改梯等工程措施相比优势明显。【结论】狼尾草草篱价格低廉、效果显著,是防治坡耕地水土流失和农业面源污染的有效措施,可在中国北方地区普遍推广。