land degradation & development Land Degrad. Develop. (2015) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ldr.2397
COST-EFFECTIVE TARGETING SOIL AND WATER CONSERVATION: A CASE STUDY OF CHANGTING COUNTY IN SOUTHEAST CHINA Chengchao Wang1*, Yusheng Yang1, Yaoqi Zhang2 1
Key Laboratory of Humid Subtropical Eco-geographical Process Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China 2 School of Forestry and Wildlife Sciences, Auburn University, AL 36849, USA Received 11 October 2014; Revised 12 March 2015; Accepted 2 May 2015
ABSTRACT Soil erosion is by far the greatest cause of land degradation and other environmental and socio-economic problems in China. Although various conservation methods are widely utilized to reduce soil erosion and to sustain agricultural production, the cost-effectiveness and selection of these methods are less known. Using our survey and ecological data, this study evaluated four soil and water conservation methods in Changting County, Southeast China. The results show that the disparity of conservation costs is much larger than that of ecological benefits. Planting fruit trees is a kind of conservation through primarily economic development. Closing hillsides for afforestation is most costeffective, followed by forest fertilizing, and planting trees and grass. Our findings suggest that comparatively lower cost conservation methods, for example closing hillsides for afforestation, should be considered in priority if initial ecological conditions can meet the requirements of the method. Copyright © 2015 John Wiley & Sons, Ltd. key words:
soil and water conservation; conservation prioritization; cost–benefit analysis; ecological benefit; China
INTRODUCTION Soil erosion is one of the most serious threats to rural sustainability in developing countries (Das & Bauer, 2012; Mekonnen et al., 2014). The fragile hilly ecosystems in these areas provide many important ecosystem services and sustain the livelihoods of most poor rural households (Persha et al., 2011). The deteriorative soil erosion caused by both unsustainable land use and poor natural conditions often results in soil fertility degradation, soil loss, catastrophic floods and debris flows, decreasing water supply, sedimentation and reservoir siltation in downstream areas, nonpoint source pollution, etc. (Zhou et al., 2009; Ghosh et al., 2010; Zhong et al., 2013; Das et al., 2014; Lieskovský & Kenderessy, 2014). These outcomes could lead to the vicious poverty–environment trap and trans-regional environmental problems (Cao et al., 2009; Wang et al., 2011). Hence, soil erosion has far-reaching economic, political, social and environmental implications owing to both on-site and off-site impacts (Thampapillai & Anderson, 1994; Ananda & Herath, 2003; Brevik et al., 2015). Different land management and conservation measures would have different effectiveness in reducing soil erosion, so selecting the suitable land management and conservation methods is crucial for reducing soil erosion (García-Orenes et al., 2010; Giménez Morera et al., 2010; Ndah et al., 2012; Xu et al., 2012; Lieskovský & Kenderessy, 2014). *Correspondence to: Chengchao Wang, Key Laboratory of Humid Subtropical Eco-geographical Process Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China. E-mail:
[email protected]
Copyright © 2015 John Wiley & Sons, Ltd.
China is one of the many typical countries suffering from severe soil erosion in the world (Zhao et al., 2013). The area of soil erosion in China is 3·57 million km2, accounting for 37·2% of the total land area. The average annual soil erosion in 2008 reached to 4·5 billion Mg accounting for about 20% of the global total soil erosion. Soil loss of major watersheds amounted to 3400 Mg km 2 yr 1(Sun, 2011). Serious soil erosion usually results in great economic loss. It was reported that the economic loss deriving from soil erosion in 1999 was estimated at RMB 54·03 billion, accounting for 0·60% of the current year’s GDP (Hao et al., 2004). Soil erosion was not only distributed in arid and semiarid regions, but also prevailed in humid subtropical China. Excessive extraction of natural resources, such as over-logging, grazing and farming, was widely claimed as the primary cause of severe soil erosion in red soil regions of southern China during the past six decades (Wang et al., 2011; Xie et al., 2013). In these areas, soil erosion has plagued livelihoods and rural sustainability for a long time. It has been well-recognized that reducing soil erosion is critical to poverty alleviation and rural sustainability (Cao et al., 2009; Wang et al., 2011). To reduce soil erosion and ameliorate subsequent problems, various soil and water conservation methods have been used in China. Because conservation methods are site specific (Atreya et al., 2008; Tesfaye et al., 2014), the selection is largely dependent on the local bio-physical and socioeconomic circumstances. In red soil regions of southern China, the methods such as closing hillsides for afforestation, planting trees and grass, forest fertilizing and planting fruit trees have been proven to be successful and have been widely utilized to restore degraded ecosystems since the last
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decade (Yue & Chen, 2003; Li et al., 2008; Gao et al., 2011; Zhong et al., 2013). However, the criteria of the evaluation were mainly based on ecological benefits measured by ecological indices (such as vegetation coverage, soil loss, biomass and productivity, soil nutrients and vegetation species) (Jiang et al., 2009; Xie et al., 2013). The method, having the largest environmental benefits, was considered the best (Yue & Chen, 2003; Li et al., 2008; Jiang et al., 2009). However, the evaluation is less meaningful if the costs are not considered. The high-ecological-benefit but low-cost-effectiveness conservation methods should not be encouraged (Messer, 2006). All conservation measures have involved costs, including acquisition costs, management costs, opportunity costs, transaction costs and damage costs (Naidoo et al., 2006; Yitbarek et al. 2012). Cost-effectiveness of conservation measures is more important to developing countries with fewer financial resources (Ferraro, 2003; Cabeza & Moilanen, 2006). The research on cost-effectiveness of conservation has been conducted in different areas. For example, the cost-effectiveness of soil and water conservation measures in limiting the reservoir siltation or the new revegetation technology in reducing roadcuts was evaluated by comparative research (Lee et al., 2013; Grimaldi et al., 2013). The cost-effectiveness between engineering measures (such as check-dams and land smoothing) and biological measures (such as forest reforestation and planting grass) was compared to optimize the conservation portfolio (Fullen et al., 2011; Quiñonero-Rubio et al., 2014). Because of the sitespecific feature of conservation methods, the cost-effective measures in one country may not be the same in other countries with different socio-ecological systems. However, costeffectiveness of conservation has not been adequately investigated. As a result, some costly measures and all financial sources have been applied in a few small areas, whereas larger areas were not conserved. It was argued that poor interdisciplinary collaboration, data shortage, lack of implementation and difficulty in quantifying ecological benefits were primary reasons (Naidoo et al., 2006; Duke et al., 2013). Cost-effective measures should be prioritized to maximize the overall benefit. But besides the cost criterion, natural conditions (such as soil erosion intensity, soil fertility and slope) should also be taken into account, because each method usually has its natural applicable conditions. In other words, prioritization should be based on economic as well as biological benefits (Balmford et al., 2000; Izquierdo & Grau, 2009). The cost per unit of soil erosion reduction is usually selected to represent the cost-effectiveness (Babcock et al., 1996; Panagopoulos et al., 2011). Therefore, conservation methods with higher integrated benefits but with lower costs are usually prioritized over other methods. Thus, it is essential to evaluate soil and water conservation methods using cost–benefit analysis. The research results would facilitate decision-making in selecting effective soil erosion control methods. The objectives of our study are to assess the costeffectiveness of four soil and water conservation methods in reducing soil erosion in southern China and to prioritize Copyright © 2015 John Wiley & Sons, Ltd.
these conservation practices. Our research is based on a case study of Changting County, Fujian Province, which is one of the greatest typical areas of soil erosion in red soil regions of southern China. The period of costs and benefits was investigated from 2000 to 2007. DATA AND METHODS Study Area and Soil Conservation Methods Changting County is located in the western Fujian Province of southeast China. It is characterized by a humid, subtropical monsoon climate, and it is primarily covered by loose granite red soils (Wang et al., 2011). In recent history, it has suffered from severe soil erosion resulting from anthropogenic and natural factors (Wang et al., 2011; Wang et al., 2012) and has gradually become one typical region of red soil erosion with higher soil erosion intensity and a long history of treatment. Specific information of natural and economic aspects can be seen in Wang et al. (2011). To mitigate ecological degradation and soil erosion, the county government has implemented various methods of soil and water conservation since the 1950s (Wang et al., 2011). The recent conservation program supported by the provincial government, with an annual compensation of RMB 10 million (US$1equaled approximately RMB 8·27 in 2000) from 2000 to 2007, achieved great success in soil erosion control (Figure 1). Scientific research attributed to
Figure 1. Changes in the landscape during the soil and water conservation project in Changting County from 2000 (Top) to 2008 (Bottom). This figure is available in colour online at wileyonlinelibrary.com/journal/ldr. LAND DEGRADATION & DEVELOPMENT, (2015)
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the development of effective conservation methods (Cao et al., 2009). Four methods (closing hillsides for afforestation, planting trees and grass, forest fertilizing and planting fruit trees) have been practiced widely (Figure 2), accounting for 99·47% of the total treatment area (see Table I). Planting fruit trees was different from other methods, and its primary objective was economic returns. The fruit trees were planted by the county government in 2000; the usage rights were transferred to some rural households by bidding in 2004. The new orchard users will return the land and trees to the county government after 30 to 50 years of lease. The criteria to determine the conservation methods are selected based on the erosion intensity and slope of the land (Table II). The applicable conditions and specific measures of each method can also be seen in Table II. It should be noted that the content of Table II has been recognized in the past few years. In practice, the conservation intensity has been higher than that of Table II since 2000. Data Collection The research period is from 2000 to 2007. Biophysical data was mainly derived from monitoring. Before the investigation, three plots (each 400 m2, 20 × 20 m) of each conservation method and matched control plots for each land use type were selected to make a total of 24 plots selected as the survey plots. Then, two significant indices of ecological restoration were investigated, including soil loss and runoff ratio. To monitor the intensity of soil erosion, we built a runoff pond with 20 m length and 5 m width in every plot. We removed all the soil from the bottom of each pond 24 h after a rain and dried three random samples of soil for 12 h at 105 °C to determine the oven-dry weight of the sediments (Ma et al., 2013). The runoff ratio was calculated by
Table I. Main methods of soil and water conservation in Changting County from 2000 to 2007 Conservation methods Closing hillsides for afforestation Planting trees and grass Forest fertilizing Planting fruit trees Total
Area (ha) 64 980 5822 3732 2472·6 77 419
Percentage (%) 83·93 7·52 4·82 3·19 100
Note: % of total treatment area. Source: Bureau of Water and Soil Conservancy in Changting County, our survey in 2013.
dividing the total water collected in the runoff ponds by the total rainfall at the site (Ma et al., 2013). Finally, we got the improvement of soil erosion by comparing the investigated results between 2000 and 2007. The costs and benefit data of four conservation methods was collected from our field survey in July, 2013. The costs of each method included labor costs required at land preparation, ditching small parallel ditches, planting, fertilization, patrolling, and costs of materials such as seedling, grass seed, fertilization, and billboards of environmental protection. In order to get the history cost data, we accessed the soil conservation planning and financial budget reports of research period at watershed level. We also interviewed 24 administrative leaders of governmental sectors, such as the Bureau of Water and Soil Conservancy and the Bureau of Forestry at county and town levels to obtain the cost data, their structure and adjustment for investigated plots. In addition, the specific material costs and labor costs of the research period were obtained through 20 households to supplement the data (Wang et al., 2011; 2012). Eventually the conservation costs at plot scale were calculated.
Figure 2. Photographs of four conservation methods in Changting County: (A) closing hillsides for afforestation, (B) planting trees and grass, (C) forest fertilizing and (D) planting fruit trees. This figure is available in colour online at wileyonlinelibrary.com/journal/ldr. Copyright © 2015 John Wiley & Sons, Ltd.
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Table II. Main methods and application conditions of soil and water conservation in Changting County Conservation methods
Application conditions
Closing hillsidesfor afforestation
Upland of light soil erosion, upland of moderate soil erosion with better site conditions, and upland far away from villages Severely eroded red soils close to villages that cannot be restored by closing hillsides, especially eroded land with small soil A horizon and high difficulty in afforestation.
Planting trees and grass
Forest fertilizing
Planting fruit trees
Low-quality Pinus massoniana forests owing to soil nutrient loss and many more than 10-year-old Pinus massoniana trees’ height is lower than 0·6 m with less than 1-m canopy. Hillsides close to villages with convenient transportation, small gradient and with better water and fertilizer conditions.
Criterion
Specific measures
Vegetation coverage >30% and soil organic matter >0·4%
Closing hillsides and prohibiting inhabitants to access
Vegetation coverage
