The Roles of Check Dams and Dam-Trapped Farmlands in the Hilly and Ravine Region of the Loess Plateau: Soil Erosion Control, Grain Production and Food Security 

Author(s):  
Baiqun Wang ◽  
Weiqin Dang ◽  
Tianmin Dang

<p>The soils are susceptible to water erosion in the hilly and ravine region of the Loess Plateau due to the readily erodible attribute of soils, erosive geomorphology, land use and land cover, and erosive rainfall. The soil and water losses induced by water erosion have the significant on-site impacts on crop growths and yields in this region because of soil nutrient depletion and adverse soil moisture condition. In addition, the crops grown in different land types frequently suffer from the seasonal draught due to climate change, which leads to the decline or failure of crop yield. Therefore, the crop yields and grain production are susceptibly stressed by soil erosion and drought in this region. Soil erosion and draught are the essential issues faced by agriculture production and eco-environment. Alternatively, effective measures of soil and water conservation can incredibly control soil and water losses induced by water erosion, alleviate the influences of draught on crop yields, and sustain grain production in this region. The check dam is one of the widely adopted engineering measures of soil and water conservation in the valleys of the hilly and ravine region on the Loess Plateau. Check dam can play multiple roles in mitigating soil erosion, trapping eroded sediments, regulating runoff and creating the lands in the valleys in the context of water erosion. The check dam can control the soil erosion to some extent because it can raise the basis level of erosion in the valley. The lost sediment and runoff can be trapped by the check dam in a watershed, which can reduce resultant loss rate of soil and water in the outlet of the watershed and mitigate sediment loads in the rive connecting to the watershed. Moreover, the check dam can make sediments or eroded soils deposit so as to develop the relatively flat lands called as the dam-trapped farmland in the valleys. The dam-trapped farmlands along with the terrace lands are regarded as the crucial farmlands due to their excellent farming conditions in this region. Some grain crops, such corn, sorghum, millet or potato, are always grown in the dam-trapped farmlands, among which corn is frequently planted in this kind of farmland. The crop yields of the dam-trapped farmlands have been increasing over the last 60 years. It is evidenced that the yield of corn increased from 2250-3000 kg/ha in 1960s to 12000-15000 kg/ha at present. The corn yield of the dam-trapped farmland is 1.5-2.0 folds of that of the terrace land. The nutrient use efficiency and water use efficiency of corn in the dam-trapped farmland are much higher than those of terrace land. It can be seen that check dam have the powerful function mitigating the losses runoff and sediment, and dam-trapped land can play the critical parts in sustaining grain production and insuring food security in the hilly and ravine region of the Loess Plateau. </p><p><strong>Keywords:</strong> soil erosion; check dam; dam-trapped farmland; grain production; food security; hilly and ravine region; Loess Plateau</p>

2020 ◽  
Author(s):  
Weiqin Dang ◽  
Baiqun Wang ◽  
Tianmin Dang

<p>It is well known that soils are vulnerable to water erosion in the hilly and ravine region of the Loess Plateau. The soil and water losses induced by water erosion have both the on-site and off-site impacts in this region, which causes the on-site decline of soil fertility and reductions of crop yields on sloping farmlands, and drains the generated overland runoff and transports the eroded soils/sediments to the off-site valleys or rivers to threaten the safety of the river systems. Constructing the check dam in the valley has the long history and is regarded as one of the powerful measures to control the soil and water losses in a watershed in this region. On the one hand, the check dam plays the vital roles in trapping the large amounts of sediment generated from the sloping lands and buffering the drainage of runoff yielded form the slopes. On the other hand, the silted sediments or eroded soils by the check dam can develop the relatively flat lands in the valleys. The check dam-trapped lands can be utilized to grow the crops and become the farmlands in a watershed. The investigation indicates that the contents of soil organic matter, nutrients and soil moisture of he check dam-trapped farmlands are higher than those of the sloping farmlands or the terraces. According to the analysis on the survey data on the crop yield evolutions in the watershed in this region, the crop yields of check dam-trapped farmlands have been significantly higher than those of the sloping farmlands and terraces in the scenario of the similar fertilizer input and crop cultivars due to the optimum soil moisture condition in the check dam-trapped farmlands. However, the check dam-trapped farmlands face some challenges under the climate change. Some of the check dam-trapped farmlands or the grown crops in these kinds of lands are susceptible to the damage arose from extreme rainstorms because of the outdated measures of soil and water conservation for these kinds of farmlands. In some watersheds, the check dam-trapped farmlands are prone to salinization due to the outdated management. Therefore,the protective measures and techniques of harnessing salinization for the check dam-trapped farmlands should be updated over time in order to keep the check dam-trapped farmlands safe and maintain the higher crop yields in those farmlands in the hilly and ravine region of the Loess Plateau.</p>


2007 ◽  
Vol 31 (4) ◽  
pp. 389-403 ◽  
Author(s):  
Liding Chen ◽  
Wei Wei ◽  
Bojie Fu ◽  
Yihe Lü

The Loess Plateau, China, has long been suffering from serious soil erosion. About 2000 years ago, larger areas were used for grain production and soil erosion was thus becoming severe with increase in human activity. Severe soil and water loss led to widespread land degradation. During the past decades, great efforts were made in vegetation restoration to reduce soil erosion. However, the efficiency of vegetation restoration was not as satisfactory as expected due to water shortage. China initiated another state-funded scheme, the `Grain-for-Green' project in 1999, on the Loess Plateau to reduce soil erosion and improve land quality. However, the control of soil erosion effectively by land-use modification raised problems. In this paper, the lessons and experiences regarding soil and water conservation in the Loess Plateau in the past decades are analysed first. Urgent problems are then elaborated, such as the contradiction between land resource and human population, shortage of water both in amount and tempospatial distribution for vegetation growth, weak awareness of the problems of soil conservation by local officials, and poor public participation in soil and water conservation. Finally, suggestions regarding soil and water conservation in the Loess Plateau are given. In order to control soil erosion and improve vegetation, a scientific and detailed land-use plan for the Loess Plateau has to be made, in the first instance, and then planning for wise use of water resources should be undertaken to control mass movement effectively and to improve land productivity. Methods of improving public awareness of environmental conservation and public involvement in vegetation rehabilitation are also important.


2020 ◽  
Author(s):  
shaobo long

<p><strong>The response of extreme rainstorm to global </strong><strong>climate pattern changes in the loess plateau</strong></p><p>Shaobo Long<sup>1,3</sup>、Jianen Gao<sup>1,2,3*</sup>、Huijuan Li<sup>5</sup>、Zhe Gao<sup>4</sup>、minmin Qiang<sup>1,3</sup>、Sixuan Liu<sup>1,3</sup></p><ol><li>Institute of Soil and Water Conservation, Northwest Agriculture and Forestry University, 712100, Yangling, Shaanxi, China.</li> <li>Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi, China.</li> <li>Research Center on Soil and Water Conservation, Ministry of Water Resources, 712100, Yangling, Shannxi, China.</li> <li>College of Water Resources and Architectural Engineering, Northwest Agriculture and Forestry University, 712100, Yangling, Shaanxi, China.</li> <li>Institute of Geographic Sciences and Natural Research, CAS, 100101, Beijing, China.</li> </ol><p><strong>Abstract: </strong>The loess plateau is the region with the most serious soil and water problems in the world, the soil erosion mainly occurs in the season of rainfall, especially the extreme rainstorm has great influence on soil erosion. In recent years, under the background of global climate change, extreme rainstorm occurs frequently in the loess plateau, causes a series of soil damage, was difficult to predict. Therefore, it is a great significance to study the rule of extreme rainstorm for the soil erosion in the loess plateau. Based on the daily rainfall data of 56 meteorological stations and global sea surface temperatures (SST) data in the last 60 years, the effects of El Niño on extreme rainstorm were studied by using empirical orthogonal function (EOF), wavelet transform, and other statistical methods. The results show:</p><ul><li>(1) The extreme rainstorm has obvious spatial distribution characteristics, which decreases gradually from the south to the north of the loess plateau; Temporal variation of extreme rainstorm has obvious decadal oscillation, showing a decreasing trend from 1982 to 2012 and an increasing trend after 2012.</li> <li>(2) There was a significant positive correlation between the time coefficient of EOF1 for SST and the extreme rainstorm (P < 0.05). Wavelet analysis shows that Both extreme rainstorm and SST anomaly have a 30-year cycle, with the time change becoming more dramatic after 2012.</li> <li>(3) El Niño has obvious influence on the extreme rainstorm in the loess plateau region. Extreme rainstorm can be predicted about 1 year in advance by the change of SST anomaly. This is of great significance to the study of extreme rainfall erosion in the loess plateau.</li> </ul><p><strong>Keywords: The loess plateau; Extreme rainstorm; El Niño</strong></p><p><strong>Funding:</strong></p><ol><li>The National key Research and Development Program of China (No.2017YFC0504703).</li> <li>National Natural Science Foundation of China (No. 41877078, 41371276).</li> <li>Knowledge Innovation Program of the Chinese Academy of Sciences (No.A315021615).</li> </ol>


2018 ◽  
Vol 10 (12) ◽  
pp. 4773 ◽  
Author(s):  
Xiaohui Huang ◽  
Lili Wang ◽  
Qian Lu

Analyzing vulnerability and adaptation to soil and water loss is an important part of the study on the human–environment relationship in the Loess Plateau. It has also provided a new perspective for studying the farmers’ adoption behavior of soil and water conservation technology in the soil erosion area of the Loess Plateau. Based on the Turner vulnerability framework, this paper constructs a household-scale index system of soil and water loss vulnerability in the Loess Plateau and evaluates the soil and water loss vulnerability in the Loess Plateau using the field survey data of the Loess Plateau applied entropy method. Finally, we use the binary logistic model to estimate the impact mechanism of farmers’ soil erosion vulnerability on farmers’ adoption behavior of soil and water conservation technology. The main conclusions are as follows: (1) In the total sample, susceptibility > exposure > adaptability, whereas in the Shaanxi and Gansu subsample, susceptibility > adaptability > exposure. The Ningxia subsample was similar to the total sample. For each index, Ningxia > Gansu > Shaanxi; (2) The exposure and susceptibility of soil and water loss have a positive impact on farmers’ adoption behavior of soil and water conservation technology, and natural capital has a positive impact on farmers’ adoption behavior of soil and water conservation technology. Physical capital has a positive impact on farmers’ adoption behavior of biological measures. Financial capital has a negative impact on farmers’ adoption behavior of biological measures and farming measures. Social capital has a positive impact on farmers’ adoption behavior of engineering measures and biological measures; (3) Overall, the marginal effect of the adoption behavior of farmers’ soil and water conservation techniques, adaptability > susceptibility > exposure. Therefore, it is necessary to strengthen the monitoring of soil and water loss, encourage the government and farmers to respond in time, and reduce the losses caused by soil erosion. Enriching the capital endowment of farmers, breaking through the endowment restriction of farmers’ adoption of soil and water conservation technology.


2020 ◽  
Author(s):  
Peng Li ◽  
Kunxia Yu ◽  
Lie Xiao

<p>Check dam is widely used in the soil erosion control in the gully on the Loess Plateau of China. Check dam has significant effects in sedimentation, erosion control, land formation, water storage, and vegetation restoration. This result shows that the main dams and medium-sized dams on the Loess Plateau had deposited 5.12 million tons of sediment by the end of 2011, reducing sediment transportation to the Yellow River. The check dam system decreases the probability of gravity erosion. Check dams increases cropland in the gully-hilly area of the Loess Plateau, thus increases grain production. The check dam project is a carbon pool. On the Loess Plateau, 123 million tons of soil carbon is storaged in the check dam, accounting for 17.08% of the carbon sequestration in afforestation projects in China from 1994 to 1998. Check dam construction increases regional vegetational coverage, and the NDVI in the Dali River watershed increased by 28.4% after the dam project. The results provide a scientific basis for the assessment of the eco-environmental benefit of check dam on the Loess Plateau of China.</p>


Author(s):  
Hui Wei ◽  
Wenwu Zhao ◽  
Han Wang

Large-scale vegetation restoration greatly changed the soil erosion environment in the Loess Plateau since the implementation of the “Grain for Green Project” (GGP) in 1999. Evaluating the effects of vegetation restoration on soil erosion is significant to local soil and water conservation and vegetation construction. Taking the Ansai Watershed as the case area, this study calculated the soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration, using the Chinese Soil Loess Equation (CSLE), based on rainfall and soil data, remote sensing images and socio-economic data. The effect of vegetation restoration on soil erosion was evaluated by comparing the average annual soil erosion modulus under two scenarios among 16 years. The results showed: (1) vegetation restoration significantly changed the local land use, characterized by the conversion of farmland to grassland, arboreal land, and shrub land. From 2000 to 2015, the area of arboreal land, shrub land, and grassland increased from 19.46 km2, 19.43 km2, and 719.49 km2 to 99.26 km2, 75.97 km2, and 1084.24 km2; while the farmland area decreased from 547.90 km2 to 34.35 km2; (2) the average annual soil erosion modulus from 2000 to 2015 under the initial and current scenarios of vegetation restoration was 114.44 t/(hm²·a) and 78.42 t/(hm²·a), respectively, with an average annual reduction of 4.81 × 106 t of soil erosion amount thanks to the vegetation restoration; (3) the dominant soil erosion intensity changed from “severe and light erosion” to “moderate and light erosion”, vegetation restoration greatly improved the soil erosion environment in the study area; (4) areas with increased erosion and decreased erosion were alternately distributed, accounting for 48% and 52% of the total land area, and mainly distributed in the northwest and southeast of the watershed, respectively. Irrational land use changes in local areas (such as the conversion of farmland and grassland into construction land, etc.) and the ineffective implementation of vegetation restoration are the main reasons leading to the existence of areas with increased erosion.


Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1054 ◽  
Author(s):  
Qiaoling Guo ◽  
Yaoyao Han ◽  
Yunsong Yang ◽  
Guobin Fu ◽  
Jianlin Li

The streamflow has declined significantly in the coal mining concentrated watershed of the Loess Plateau, China, since the 1970s. Quantifying the impact of climate change, coal mining and soil and water conservation (SWC), which are mainly human activities, on streamflow is essential not only for understanding the mechanism of hydrological response, but also for water resource management in the catchment. In this study, the trend of annual streamflow series by Mann-Kendall test has been analyzed, and years showing abrupt changes have been detected using the cumulative anomaly curves and Pettitt test. The contribution of climate change, coal mining and SWC on streamflow has been separated with the monthly water-balance model (MWBM) and field investigation. The results showed: (1) The streamflow had an statistically significant downward trend during 1955–2013; (2) The two break points were in 1979 and 1996; (3) Relative to the baseline period, i.e., 1955–1978, the mean annual streamflow reduction in 1979–1996 was mainly affected by climate change, which was responsible for a decreased annual streamflow of 12.70 mm, for 70.95%, while coal mining and SWC resulted in a runoff reduction of 2.15 mm, 12.01% and 3.05mm, 17.04%, respectively; (4) In a recent period, i.e., 1997–2013, the impact of coal mining on streamflow reduction was dominant, reaching 29.88 mm, 54.24%. At the same time, the declining mean annual streamflow induced through climate change and SWC were 13.01 mm, 23.62% and 12.20 mm, 22.14%, respectively.


Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 20 ◽  
Author(s):  
Yaping Wang ◽  
Wenzhao Liu ◽  
Gang Li ◽  
Weiming Yan ◽  
Guangyao Gao

The tableland-gully region is one of the main topographic-ecological units in the Chinese Loess Plateau (CLP), and the soil in this region suffers from serious water erosion. In recent years, much work has been conducted to control soil erosion in this area. This paper summarized the development of soil and water conservation researches in the CLP from the bibliometric perspective based on the Science Citation Index (SCI) and Chinese National Knowledge Infrastructure (CNKI) databases. The quantity of SCI literatures has increased rapidly since 2007, with an average annual growth rate of 21.4%, and the quantity of CNKI literatures in the last decade accounted for 62% of the past 30 years. The development trends showed that early SCI research was related to loess geology in the context of ecological remediation, while the CNKI literature focused on agricultural production under comprehensive management. Over time, the research themes of the two databases gradually became unified, i.e., the management of sloping farmland and the improvement of agricultural productivity. Subsequently, the themes gradually extended to the disposition of comprehensive control measures for soil erosion and the environmental effect of agro-fruit ecosystems. The highly cited papers mainly focused on soil reservoir reconstruction, soil erosion factors, and environmental effects of vegetation restoration. Two aspects need further study, including (i) the effect of soil erosion control under different ecological remediation patterns; and, (ii) the ecosystem maintenance mechanism and regulation approaches that are based on the sustainable utilization of soil and water resources in the tableland-gully region of the Loess Plateau.


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