Time and scale of gully erosion in the Jedliczny Dol gully system, south-east Poland

Key catchments of the Roztocze loess area in south-east Poland have a great potential of revealing the history of long-term soil erosion and changes in land use. The knowledge of how and when soil erosion took place in the past helps one understand the impact of land use changes on the landscapes [Bork, H.-R., 1989. Soil erosion during the past Millennium in Central Europe and its significance within the geomorphodynamics of the Holocene. Catena 15, 121–131]. The Jedliczny Dol gully system near the town Zwierzyniec in south-east Poland was investigated by using detailed field stratigraphy and radiocarbon dating of charcoal and wood.In connection with new settlements which were established between the 14th and 16th centuries, arable land was cultivated and forests were used much more intensively. As a consequence, the loess soils were strongly eroded during heavy rainfalls. Up to 4 m of colluvial sediments were deposited in the gully system during the 15th and/or 16th centuries. The thickness of the colluvial sediments indicate severe erosion which might be related to excessive timber exploitation for the local glass and iron production. With the foundation of the so-called Ordinariat Zamoyski at the end of the 16th century, some parts of the area were presumably reforested. High pressure on the land at the beginning of the 19th century enabled a second main phase of gulling before 1900.Since 1890 at the latest, almost the whole catchment is used as a forest, however, concentrated runoff on compacted forest roads can still be high after heavy rainfalls.In loess areas soil erosion caused by intensive land use, triggered by heavy rainfalls, can change the landscape drastically. These changes will continue to influence how catchments react, even if land use gets less intensive again. This knowledge should be considered regarding future, sustainable land use and recent changes in land use in the south-eastern Polish loess regions.     

Measurement and modelling of the effects of initial soil conditions and slope gradient on soil translocation by tillage

Tillage erosion studies have mainly focused on the effect of topography and cultivation practices on soil translocation during tillage. However, the possible effect of initial soil conditions on soil displacement and soil erosion during tillage have not been considered. This study aims at investigating the effect of the initial soil conditions on net soil displacement and the associated erosion rates by a given tillage operation of a stony loam soil. Tillage erosion experiments were carried out with a mouldboard plough on a freshly ploughed (pre-tilled) soil and a soil under grass fallow in the Alentejo region (Southern Portugal).

The experimental results show that both the downslope displacement of soil material and the rate of increase of the downslope displacement with slope gradient are greater when the soil is initially in a loose condition. This was attributed to: (i) a greater tillage depth on the pre-tilled soil and (ii) a reduced internal cohesion of the pre-tilled soil, allowing clods to roll and/or slide down the plough furrow after being overturned by the mouldboard plough.

An analysis of additional available data on soil translocation by mouldboard tillage showed that downslope displacement distances were only significantly related to the slope gradient when tillage is carried out in the downslope direction. When tillage is carried out in the upslope direction, the effect of slope gradient on upslope displacement distances was not significant. This has important implications for the estimation of the tillage transport coefficient, which is a measure for the intensity of tillage erosion, from experimental data. For our experiments, estimated values of the tillage transport coefficient were 70 and 254 kg m⁻¹ per tillage operation for grass fallow and pre-tilled conditions, respectively, corresponding to local maximum erosion rates of ca. 8 and 35 Mg ha⁻¹ per tillage operation and local maximum deposition rates of ca. 33 and 109 Mg ha⁻¹ per tillage operation.     

Early soil knowledge and the birth and development of soil science

Soils knowledge dates to the earliest known practice of agriculture about 11,000 BP. Civilizations all around the world showed various levels of soil knowledge by the 4th century AD, including irrigation, the use of terraces to control erosion, various ways of improving soil fertility, and ways to create productive artificial soils. Early soils knowledge was largely based on observations of nature; experiments to test theories were not conducted. Many famous scientists, for example, Francis Bacon, Robert Boyle, Charles Darwin, and Leonardo da Vinci worked on soils issues. Soil science did not become a true science, however, until the 19th century with the development of genetic soil science, led by Vasilii V. Dokuchaev. In the 20th century, soil science moved beyond its agricultural roots and soil information is now used in residential development, the planning of highways, building foundations, septic systems, wildlife management, environmental management, and many other applications in addition to agriculture.     

A detailed reconstruction of changes in the factors and parameters of soil erosion over the past 250 years in the forest zone of European Russia (Moscow region)

Accelerated soil erosion is a major threat to soil, and there are great variations in the rate of soil erosion over time due to natural and human-induced factors. The temperate forest zone of Russia is characterized by complex stages of land-use history (i.e. active urbanization, agricultural development, land abandonment, etc.). We have for the first time estimated the rates of soil erosion by the WaTEM/SEDEM model (rainfall erosion) and by a regional model (snowmelt erosion) over the past 250 years (from 1780 to 2019) for a 100-km² study site in the Moscow region of Russia. The calculations were made on the basis of a detailed historical reconstruction of the following factors: the location of the arable land, crop rotation, the rain erosivity factor, and the maximum snow water equivalent. The area of arable land has decreased more than 3.5-fold over the past 250 years. At the end of the 20th century, the rates of gross erosion had declined more than 5.5-fold (from 28 × 10³ to 5 × 10³ t?ha^?1?yr^?1) in comparison with the end of the 18th century. Changes in the boundaries of arable land and also the relief features had led to a significant intra-slope accumulation of sediments. As a result of sediment redeposition within the arable land, the variation in net soil erosion was significantly lower than the variation in gross soil erosion. The changes in arable land area and in crop composition are the factors that have to the greatest extent determined the changes in soil erosion in this territory.     

1986-2013年南京市土地利用变化对土壤侵蚀的影响

为了了解南京市土地利用变化对土壤侵蚀的响应,基于气象、土壤、地形、遥感等多源数据,运用GIS和统计方法分析了南京市1986—2013年的土地利用/覆被时空动态变化特征,并运用RUSLE模型定量评估了南京市的土壤侵蚀时空变化特征。结果表明:(1)全市土壤侵蚀呈现先增加后减少的趋势:1986—1996年南京市土壤侵蚀面积增加了132.95 km²,由324.11 km²增加到457.06 km²; 1996—2013年土壤侵蚀面积比从7.46%减少到2.45%,由457.06 km²减少到150.11 km²。空间分布结果表明南京市土壤侵蚀主要发生在生产建设活动较为频繁的丘陵山区。(2)全市不同等级侵蚀面积与对应的侵蚀量呈明显的倒挂现象,较高等级侵蚀区应当是重点治理区域。(3)土地利用类型是影响南京市土壤侵蚀的因素之一,87%以上的土壤侵蚀量动态变化集中在林地和耕地。值得注意的是,水域、居民点及建设用地和其他用地变化对土壤侵蚀无明显影响,而耕地变化对土壤侵蚀具有明显的负面影响,林地和草地变化对土壤侵蚀既具有负影响也具有正影响,以正面影响为主,主要是因为林地既转变成耕地也转变成居民点及建设用地和水域,不同时期其主要影响也不同。综上,该研究结果可为南京市土地资源配置及水土流失防治提供科学参考和理论依据。     

2000-2018年皖南山区土壤侵蚀时空变化

[目的]精确评估皖南山区土壤侵蚀量并分析其时空变化特征,为区域水土流失综合治理提供科学依据.[方法]在GIS技术的支持下,利用研究区日降雨数据,30 m分辨率DEM,土壤数据和土地利用等数据,采用中国土壤流失方程(CSLE)估算皖南山区土壤侵蚀模数,并分析2000,2010和2018年近20 a研究区土壤侵蚀时空变化特...     

Ridge tillage and contour natural grass barrier strips reduce tillage erosion

Large amounts of soil are eroded annually from tilled, hilly upland soils in the humid tropics. Awareness has been increasing that much of this erosion may be due to tillage operations rather than water-induced soil movement. This field study estimated soil translocation and tillage erosion for four tillage systems on Oxisols with slope gradients of 16–22% at Claveria, Misamis Oriental, Philippines. Soil movement was estimated using ‘soil movement tracers' (SMT) which consisted of painted 12-mm hexagonal steel nuts. The SMT were buried in three replicate plots of the following tillage treatments: (1) contour moldboard plowing in the open field (MP-open); (2) contour ridge tillage in the open field (RT-open); (3) contour moldboard plowing plus contour natural grass barrier strips (MP-strip); and (4) contour natural grass barrier strips plus ridge tillage (RT-strip). Two hundred SMT were placed at the 5-cm depth at 5-cm spacings on 10 rows and 20 columns in two microplots within each plot. The microplots were oriented with the boundaries running downslope and along the contour of each 8-m-wide × 38-m-long (downslope) tillage plot. After tilling the land for four successive corn (Zea mays L.) crops (20 tillage operations), the SMT were manually excavated and their positions recorded. Recovery of SMT ranged from 82% to 85%. Displacement of SMT was directly related to slope length, percent slope, and tillage method. Mean displacement distance of SMT during the four corn growing seasons was 3.3 m for MP-open, 1.8 m for RT-open, 1.5 m for the RT-strip, and 2.2 m for MP-strip. Based on tillage operations associated with two corn crops per year, mean annual soil flux was estimated to be 241, 131, 158 and 112 kg m⁻¹ for MP-open, RT-open MP-strip, and RT-strip, respectively. Compared to the mean annual soil loss for MP-open of 63 Mg ha⁻¹, soil loss was reduced by 30%, 45%, and 53% for the MP-strip, RT-open, and RT-strip systems, respectively. Both ridge tillage and natural grass barrier strips reduced soil displacement, soil translocation flux, and tillage erosion rates.     

Land‐use evolution and degradation in Lesvos (Greece): a historical approach

An analysis has been undertaken of the land‐use evolution in the island of Lesvos for the last 5000 years, based on historical and archaeological documents and recent soil and vegetation survey data. A series of maps were compiled using historical documents for the period from 3300 bc to 1886 bc and vegetation field survey data for the period from 1886–1996. A soil survey (scale 1:50 000) was conducted in 1996 in order to relate the land‐use changes to the present physical environment. Cultivation of the land started around 3300 bc and intensified during the 18th century bc . During the Roman period forests were already significantly reduced to satisfy the increasing demands for agricultural products, timber and heating. In the Byzantine period (4th–15th century), vineyards and pastures expanded, mainly by clearing the forests. Olive plantations increased during the 13th century, motivated by the allocation of subsidies. During the first centuries of the Ottoman period, there was a further expansion of olive groves and pastures by reducing forests, while vineyards declined. Great changes occurred in the last century in the geographical distribution and the total area occupied by the various types of land use. Olive groves significantly expanded and were redistributed covering more fertile and productive land on hilly areas by clearing mainly pine forests. Oak forests increased on previous pasture areas. Today, pasture is the main type of land use in hilly areas. These previously forested areas have been cleared without any accompanying measures against soil erosion. This highly degraded land with shallow and severely eroded soils is not able to sustain any profitable agricultural use or natural forest. However, areas cultivated with olives remained sustainable for more than seven centuries without being significantly degraded. Copyright © 2000 John Wiley & Sons, Ltd.     

Landscape analysis of dynamic soil erosion in Subtropical China: A case study in Xingguo County, Jiangxi Province

As a case study on landscape pattern analysis of soil erosion change, Xingguo County in Jiangxi Province, China, was once one of the most severely eroded regions in Subtropical China. However, its soil erosion has been completely controlled in recent years. This county was historically full of forest as well as waterways that were well protected and soil erosion was seldom seen even by the mid-19th century. However, large areas of forest were destroyed after that period due to over-logging, which resulted in excessive erosion, bare hills, and mountains devoid of vegetation. Fortunately, soil erosion in Xingguo has been controlled gradually since 1982 after the county was appointed as 1 of the 8 Key National Level Erosion Control Regions. In this study, a raster (grid) soil erosion map was collected on the basis of soil erosion intensity maps from 1958, 1975, 1982 and 2000 with the aid of GIS software (ARC/INFO). Over 10 landscape indices were calculated using FRAGSTATS software for landscape pattern analysis. A set of free spatial statistics that address a fundamental problem in GIS, and soil erosion distribution patterns and their changes in the county were quantitatively analyzed at the landscape and class levels, respectively. Moreover, transformations of soil erosion types from 1958 to 1975, 1975 to 1982, and 1982 to 2000 were also calculated using the CROSSTAB module in IDRISI software. Results showed that at the landscape level, heterogeneity of soil erosion decreased. This was supported by decreasing tendencies of patch indices SHDI (Shannon’s diversity index), SHEI (Shannon’s evenness index), and IJI (Interspersion and juxtaposition index). This indicates that most of the severely eroded soil types were transformed into non-apparently eroded or slightly eroded types. Meanwhile, at the class level, a consistent pattern was found where the surface areas of non-apparently eroded or slightly eroded lands increased, and moderately, severely, very severely and extremely eroded lands deceased. In general, soil erosion in Xingguo County experienced three pronounced phases during the study periods: the exacerbation phase (1958–1975), the alleviation phase (1975–1982), and the overall alleviation phase (1982–2000). By the year 2000, 74.6% of total territory of this county was covered by land with no significant soil loss, indicating that severe soil erosion had been substantially controlled.     

基于RS/GIS的布哈河流域土壤侵蚀现状研究

利用遥感和GIS的方法获得了流域内年降水量、年均气温、地形、土壤类型和土地覆被类型等5种评价因子数据,在GIS中通过建模及空间分析,获得了布哈河流域土壤侵蚀强度等级类型及空间分布信息。结果表明,研究区土壤侵蚀总面积是14 337km2,其中轻度侵蚀和中度侵蚀面积居多,分别占土壤侵蚀总面积的54.88%和20.51%;剧烈侵蚀面积占土壤侵蚀总面积的0.63%。     

基于RUSLE模型的孙水河流域土壤侵蚀空间分异特征

土壤侵蚀一直是我国开展区域生态环境治理所关注的热点问题之一.在RS和GIS技术支持下,基于RUSLE模型分析了凉山州孙水河流域不同土地利用类型、海拔和坡度条件下土壤侵蚀强度的特征,定量评价了研究区土壤侵蚀空间特征.结果表明:孙水河流域平均土壤侵蚀模数为1954.32 t/(km2·a),土壤侵蚀严重区域主要集中于孙水河...     

中国四川盆地地区侵蚀斜坡土壤酶活性研究

Determining how soil erosion affects enzyme activity may enhance our understanding of soil degradation on eroded agricultural landscapes. This study assessed the changes in enzyme activity with slope position and erosion type by selecting water and tillage erosion-dominated slopes and performing analyses using the ¹³⁷Cs technique. The ¹³⁷Cs data revealed that soil loss occurred in the upper section of the two eroded slope types, while soil accumulation occurred in the lower section. The invertase activity increased downslope and exhibited a pattern similar to the ¹³⁷Cs data. The spatial patterns of urease and alkaline phosphatase activities were similar to the ¹³⁷Cs inventories on the water and tillage erosion-dominated slopes, respectively. On both the eroded slope types, the invertase activity and soil organic carbon content were correlated, but no correlation was observed between the alkaline phosphatase activity and total phosphorus content. Nevertheless, the urease activity was correlated with the total nitrogen content only on the water erosion-dominated slopes. The enzyme activity-to-microbial biomass carbon ratios indicated high activities of invertase and urease but low activity of phosphatase on the water erosion-dominated slopes compared with the tillage erosion-dominated slopes. Both the invertase activity and the invertase activity-to-microbial biomass carbon ratio varied with the slope position. Changes in the urease activity-to-microbial biomass carbon ratio were significantly affected by the erosion type. These suggested that the dynamics of the invertase activity were linked to soil redistribution on the two eroded slope types, whereas the dynamics of the urease and alkaline phosphatase activities were associated with soil redistribution only on the water or tillage erosion-dominated slopes, respectively. The erosion type had an obvious effect on the activities of invertase, urease and alkaline phosphatase. Soil redistribution might influence the involvement of urease in the N cycle and alkaline phosphatase in the P cycle. Thus, enzyme activity-to-microbial biomass ratios may be used to better evaluate microbiological activity in eroded soils.     

长江流域水土流失历史发展过程探讨

长江流域水土流失的发生、发展和加剧 ,经历了长期的历史过程。据历史资料分析 ,长江流域在公元 10世纪前植被茂密 ,水土流失轻微 ;公元 10— 17世纪 ,水土流失有所发展 ;特别是 17世纪中叶以来 ,人口剧增 ,山丘过度开发 ,水土流失不断加剧 ,逐渐成为重大环境问题。人类对土地资源的不合理开发利用是导致水土流失的主导因素。     

粤西坡地土壤侵蚀特征及退化分析——以广东省郁南县大湾镇为例

坡地是广东省重要的土地资源,也是水土流失的策源地。研究坡地的土壤侵蚀及退化问题,对于坡地的可持续利用具有重要的意义。本文以广东省郁南县大湾镇为例,探讨了粤西典型坡地不同侵蚀区的侵蚀形态特征,以及土壤侵蚀所导致的坡地退化,分析了影响土壤退化的原因,并提出了退化坡地的整治措施。研究区以花岗岩发育的弱侵蚀强度为主,占总侵蚀面...     

北方农牧交错带风水蚀复合区水土流失现状与综合治理对策

风水蚀复合区是中国北方农牧交错带的一部分。区域的东面与南面毗邻水蚀地貌形态,东南界为沙漠化土地发生、发展的东南界;区域的西面与北面与风蚀地貌形态接壤,西北界为旱作农业的西北界。复合区包括74个县（旗）,面积42．77万km^2,总人口2400万（2004年）。主要生态问题为：沙漠化持续发展,沙尘暴频发;土地退化严重,承载力急剧下降;生态环境恶化,自然灾害频繁。复合区水土流失的主要特点表现为风水蚀在时间上交错,空间上叠加。受侵蚀营力系统与环境系统的制约,水土流失类型表现出明显的地域分异规律。2000年水土流失面积26万1517．35km^2,占全区土地面积的61．14％;复合区每年流失土壤11．97亿t,其中水力侵蚀量5．55亿t,风力侵蚀量6．42亿t。近20多年来,复合区大部分地区的水土流失面积有所减少,侵蚀强度有所降低。随着国家加大生态建设的力度,预计在未来的十到几十年,复合区的水土流失态势将呈现逐步逆转的趋势,但局部的水土流失状况依然很严峻。风水蚀复合区水土流失治理要以预防为主、保护领先为原则,生物措施、农业技术与工程措施相结合综合治理,把国家的生态需求与农户的经济需求相结合,依法协调经济开发与环境保护的关系,注重科学研究,提高科技含量。根据风水蚀复合区现状,提出了一些治理工程项目,主要包括复合区黄河粗泥沙综合治理工程和生态修复工程。这些工程的实施,将大大减少进入黄河的粗泥沙量,风水蚀复合区水土流失状况可以得到改善。     

The WEELS model: methods, results and limitations

Within the European Union (EU)-funded Project ‘Wind Erosion on European Light Soils’ (WEELS), a model was designed and implemented with the aim of predicting the long-term spatial distribution of wind erosion risks in terms of erosion hours and wind-induced soil loss. In order to ensure wide applicability, the model structure consists of a modular combination of different approaches and algorithms, running on available or easily collected topographic and climatological data input. Whereas the ‘WIND’, ‘WIND EROSIVITY’ and ‘SOIL MOISTURE’ modules combine factors that contribute to the temporal variations of climatic erosivity, the ‘SOIL ERODIBILITY’, ‘SURFACE ROUGHNESS’ and ‘LAND USE’ modules predict the temporal soil and vegetation cover variables that control soil erodibility. Preliminary simulations over a 29-year period for the Barnham site (UK) (1970–1998) and a 13-year period for the Grönheim site (Germany) (1981–1993) generally resulted in a higher erosion risk for the English test site, where the total mean soil loss was estimated at 1.56 t ha⁻¹ year⁻¹ and mean maximum soil loss at about 15.5 t ha⁻¹ year⁻¹. The highest rates exceeded 3 t ha⁻¹ in March, September and November. On the northern German test site, the total mean soil loss was 0.43 t ha⁻¹ year⁻¹. The highest erosion rates were predicted in April when they can exceed 2.5 t ha⁻¹. The total mean maximum soil loss at this site of about 10.0 t ha⁻¹ year⁻¹ corresponds to a loss of about 0.65 mm. Predictions based on a land use scenario for the German site revealed that the erosion risk could be reduced significantly by changing land use strategies.     

Soil fertility affected by land use history,relief position,and parent material under a tropical climate in NW-Vietnam

In Vietnam as much as half of the total land area is already degraded by soil erosion and nutrient depletion. In particular, degradation due to deforestation is increasingly affecting mountainous areas in north-western Vietnam. The necessity to safeguard the farmers' livelihoods requires sustainable resource management, which firstly requires a qualitative and quantitative evaluation of resources. The objectives of the present study were to (1) identify the dominant soil types and their vulnerability using elicitation of local soil knowledge, (2) characterise the physical and chemical properties of the soils and (3) link them to the relief position and land use in order to (4) initiate sustainable soil use based on recommendations deduced from objectives (1) to (3). These objectives were achieved also by the elicitation of local knowledge. The final aim of the study was to initiate sustainable soil use based on recommendations for sustainable land use scenarios. The Chieng Khoi commune in Son La province of northern Vietnam was chosen as representative for other erosion-prone Southeast Asian sloping areas. In a participatory approach, combining local and scientific knowledge, sixteen sites were selected, representative for distinct relief positions, parent material (sand stone and silt stone), land use history, and erosion hazard. Chemical (e.g. content of organic matter, nitrogen, cation exchange capacity, base saturation, and plant available phosphorous) and physical properties (e.g. air capacity, plant available water) were used to estimate soil fertility. The predominant reference soil groups in the study area are Alisols and Luvisols, with a high diversity in respect to soil fertility. These soils are locally named ‘red soil’ and ‘black soil’, respectively. Although the main physical processes are erosion and selective sedimentation, farmers tend to underestimate their impact and causes, whereas soil quality was well-evaluated. Soils with high fertility were found on less eroded upper parts of hills and at sites, where agricultural use started only recently. Once degraded by cultivation practices, soils derived from sandstone did not recover even after more than 50 years of fallow. As a result of unsustainable land use, soils on middle and lower slopes are often affected by severe soil erosion, whereas foot slope soils suffer from accumulation of eroded infertile subsoil material as well as stagnic conditions. This study showed that unsustainable land use at upslope landscape positions has a severe impact on downslope areas. The elicitation of local knowledge facilitated the identification of such hot spots, allowing the implementation of spatially targeted conservation measures.     

Soil erosion: An important indicator for the assessment of land degradation neutrality in Russia

This review of soil erosion (SE) studies in Russia focuses on two main tasks: (i) ensuring the completeness and reliability of SE data in Russia, a large country (17.1 million km²) with a variety of natural and socio-economic causes of land degradation, (ii) assessing the possibility of including a SE indicator among the indicators of land degradation neutrality (LDN). A wide range of statistical, remote sensing, mathematical modeling data, the results of scientific and field studies obtained at different levels were analyzed. It is asserted that in Russia the total area of eroded lands and those under erosion risk occupy more than 50% of all agricultural lands, whereas soil fertility of croplands decreased in Soviet time (from 1950s to 1980s) by 30–60% only due to water erosion. However, recent scientific studies indicate a decrease in erosion rate and in the area of eroded land during the last 30–40 years as a result of abandonment of arable land and subsequent overgrown with natural vegetation. The climate change resulting in decrease of the depth of soil freezing, flow of spring runoff also adds to the decrease of soil erosion. The SE indicator was suggested as an important complement to three global LDN indicators. At national and subnational level, it can be interpreted through such indices as “Rate of soil loss” (ton ha-1 yr-1) and “Total soil loss” (1000 tons, in certain area during selected time period). At local level the set of indices can be wider and site-specific, including those obtained through remote sensing data by using the classifier of thematic applications of remote sensing technologies; the example was tested at the local site.     

Assessment of tillage translocation and tillage erosion by hoeing on the steep land in hilly areas of Sichuan, China

Most of the tillage erosion studies have focused on the effect of tractor-plough tillage on soil translocation and soil loss. Only recently, have a few studies contributed to the understanding of tillage erosion by manual tillage. Furthermore, little is known about the impact of tillage erosion in hilly areas of the humid sub-tropics. This study on tillage erosion by hoeing was conducted on a purple soil (Regosols) of the steep land, in Jianyang County, Sichuan Province, southwestern China (30°24′N and 104°35′E) using the physical tracer method.

The effects of hoeing tillage on soil translocation on hillslopes are quite evident. The tillage transport coefficients were 26–38 kg m⁻¹ per tillage pass and 121–175 kg m⁻¹ per tillage pass respectively for k₃- and k₄-values. Given that there was a typical downslope parcel length of 15 m and two times of tillage per year in this area, the tillage erosion rates on the 4–43% hillslopes reached 48–151 Mg ha⁻¹ per year. The downslope soil translocation is closely related to slope gradient. Lateral soil translocation by such tillage is also obvious though it is lower than downslope soil translocation. Strong downslope translocation accounts for thin soil layers and the exposure of parent materials/rocks at the ridge tops and on convexities in the hilly areas. Deterioration in soil quality and therefore reduction in plant productivity due to tillage-induced erosion would be evident at the ridge tops and convex shoulders.     

耕作侵蚀及其对土壤肥力和作物产量的影响研究进展

在坡耕地景观内,由于农耕工具和重力作用而引起的耕作位移使土壤发生向下坡运动或向上坡运动(依赖于耕作方向),导致净余土壤量向下坡传输、堆积,重新分配,从而形成耕作侵蚀。试验研究表明耕作侵蚀是坡耕地的主要侵蚀形式之一,耕作侵蚀发生最严重的区域是坡度较大、坡体短的坡耕地。该文就耕作侵蚀的概念、发生机理、典型的耕作侵蚀模型的发展,以及耕作侵蚀对土壤肥力和作物产量影响的研究现状作了简要论述,特别总结了针对中国的地貌和耕作工具特征而进行的耕作侵蚀的研究成果。指出在一定的景观范围内,耕作侵蚀是十分严重的,甚至其严重程度已经超过了水蚀。但是相对于水蚀而言,耕作侵蚀研究还很少,因此加强耕作侵蚀的研究是十分必要的。只有这样才能正确评价农耕地侵蚀状况,准确制定土壤保持措施和采用减少耕作侵蚀力的耕作工具,从而有效地控制土壤侵蚀。