The scarcity of arable land has become a vital issue in China. As the most populous country in the world, China has witnessed a dramatic decline in arable land due to large-scale urban expansion since the economic reform implemented in 1978 [1
]. To halt the decline in arable land, the Chinese government proposed the “arable land requisition-compensation balance” (ALRB) policy in 1997. This policy stipulated that any losses of arable land to construction land must be replaced by reclaiming the same amount of new arable land [2
]. The ALRB policy has now been implemented for nearly 20 years, however, many observations highlight that there is a trend of consuming the best arable land for urbanization while reclamation of less productive land [3
]. In addition, a large part of reclaimed arable land has been observed to be in areas with a high elevation, poor soil quality, or an underdeveloped agricultural infrastructure; such lands are unsuitable for agricultural use, resulting in a large amount of idle land [5
]. Indeed, the utilization of reclaimed land is one of the most direct reflections of the policy’s effectiveness. However, due to the lack of follow-up monitoring, the utilization status of reclaimed land remains unclear. In this regard, a precise depiction of the utilization status of reclaimed land and its mechanism should make a critical contribution to sustainable land use planning and policy decision making.
The ALRB policy focuses on the balance between arable land losses from construction occupation and arable land reclamation, which is one of the strictest arable land protection policies in China. In the cases of occupying arable land for construction, the local government is supposed to be responsible for reclaiming the same amount of arable land. This newly increased arable land, in the official Chinese definition, is called reclaimed arable land, and it is planned to be plowed and planted with crops in recent years [4
]. Land exploitation, land rehabilitation, and land consolidation are usually the three methods of reclaiming arable land. Land exploitation means the conversion of natural areas such as grassland and forest land into arable land. Land rehabilitation refers to the conversion of construction land or previously damaged land into arable land. Land consolidation aims to increase the effective area of arable land by combining small farm plots into a larger plot, and it reduces the area of field paths and ditches to make the area allow agricultural mechanization [3
]. Several studies have noted that land exploitation is the major approach for gaining arable land in China and that it has serious negative environmental and ecological consequences, such as soil erosion, flooding, and land degradation [4
]. In China, whether a plot is reclaimed or not is decided by local governments, but the subsequent cultivation of reclaimed land depends on the will of farmers. In this context, two questions arise: (1) what is the degree of reclaimed lands used for farming; and (2) what determinants affect the utilization progress of reclaimed lands?
There has been substantial literature assessing arable land conversion in China from multidisciplinary perspectives, including arable land loss due to urbanization [6
], arable land quality and agricultural productivity [10
], agricultural land fragmentation and landscape change [14
], and policy evaluation [3
]. However, there are fewer studies on arable land reclamation, and these assessments mainly focus on the changes in quantity and quality induced by arable land occupation and reclamation [3
]. No study has systematically examined the utilization of reclaimed arable lands. In essence, assessing the utilization of reclaimed lands is a direct way to measure the effectiveness of land reclamation projects under the ALRB policy. Therefore, it is necessary to understand the utilization status of reclaimed arable land in China.
In this paper, we aim to examine the spatial and temporal patterns of the utilization of reclaimed land and to identify its determinants. With the case of Wenzhou Region, a wealthy coastal city in China with limited land endowments, our specific objectives are as follows: (1) to characterize the utilization patterns of reclaimed land, which have been derived from GaoFen-2 high resolution satellite images and Google Earth images; (2) to quantify the factors promoting reclaimed land cultivation using logistic regression at the parcel scale; and (3) to discuss the implications for decision making with regard to land management and ecological protection.
4.1. Low Utilization Efficiency of Reclaimed Arable Lands
Our findings indicate a low utilization efficiency of reclaimed arable lands in Wenzhou, with less than 40% of the total reclaimed lands being used for cultivation. The reclamation projects mainly occurred in the southwest hilly areas, and most of the reclaimed arable lands were established in places previously used as grassland and forest. Similar findings with regard to the reclamation of pastureland and deforestation were also prevalent in the northwest arid and semiarid areas of China, especially in Inner Mongolia and Xinjiang Province [4
]. The reason for this finding is that, compared to the conversion of construction land, the reclamation of forest and grassland for arable land is relatively low-cost and easy to conduct. However, this increase in arable land is made at the expense of the ecosystem.
More than 60% of the reclaimed lands in the study area were still bare or had been taken over by forest, leading to both financial and resource waste. From the perspective of maintaining a dynamic balance of the quantity of arable land, the actual area of total arable land had decreased because these lands were not cultivated and had no practical utility. Furthermore, the soil and water conservation ability of bare land is poor, which could pose the potential risk of soil erosion and land degradation [41
]. In addition, part of the reclaimed lands had been covered by grasses and trees in 2016 due to the long period of time lying idle, and they may be re-developed as arable land again. This inappropriate use of land could lead to a vicious circle of “reclamation–lying idle–forest re-growth–reclamation”.
4.2. Relative Roles of Geo-Physical, Proximity, and Neighborhood Factors in Reclaimed Land Utilization
This study employed a logistic regression model to identify the determinants that best explain the utilization progress of reclaimed arable lands in Wenzhou by integrating a range of geo-physical, proximity, and neighborhood factors. The results showed positive effects of higher soil fertility and adjacency to arable lands and negative effects of higher altitudes, increased distances to rural residential areas, adjacency to forests, and location in the ecological protection zone. Among the three types of determinants, the neighborhood variables were the most important. These findings generally confirm the study hypothesis that the utilization of reclaimed land occurred where the cultivation costs were low and potential productivity was high.
The regression for reclaimed land utilization showed that cultivation occurred in areas that have better geo-physical conditions (e.g., a low elevation and high soil fertility). A negative association between elevation and the likelihood of land utilization was expected and consistent with previous findings [42
]. This result should be attributed to the greater accessibility and fewer restrictions on cultivation [29
]. The cultivation potential of reclaimed land was also constrained by soil fertility, as demonstrated in our study, in which cultivation activities were more likely to occur on fertile soils. Some researchers have indicated that soils of high fertility are usually the last to be abandoned [44
]. It makes sense that fertile soils could provide sufficient nutrition and have high value for agriculture.
Dist_rural was a negative explanatory variable, suggesting that reclaimed lands far from rural residential areas would experience a lower probability of cultivation. This result coincided with previous studies showing that land cultivation was mainly found in areas close to villages [43
]. A higher proximity to rural residential areas guarantees a farming labor supply. Farmers may value accessibility benefits because they reduce distance and the costs of tillage. Therefore, the distance to rural residential areas became a crucial determinant of farmers’ decision to cultivate reclaimed land.
Neighborhood variables exerted a decisive impact on the reclaimed arable land utilization process. Pct_forest had the greatest negative influence on the probability of reclaimed land utilization, followed by Adj_forest. In this study, we observed that many uncultivated arable lands were individual parcels within a forest matrix. Areas in the neighborhood exhibiting similar factors and, therefore, parcels isolated by forests showed a much higher propensity for lying idle than those in close proximity to other arable parcels. This finding indicates a tendency toward a homogenous arable land structure. Previous studies have also found that neighboring forests act as a source of seeds and have a heavy influence on nearby land parcels through seed dispersal, which can cause reforestation [48
]. In addition to the neighboring forest cover, Adj_arable had beneficial effects on land utilization. The closeness to forests and isolated arable land parcels would decrease tillage accessibility and increase production costs, also demonstrating the significance of profit maximization for land use [23
]. Furthermore, adjacency to arable lands would increase tillage accessibility and could provide a more complete agricultural infrastructure. A lower probability of land cultivation was found on parcels located in the ecological protection zone. This negative influence might be the result of the greater number of seed sources and the larger populations of animal dispersers in the ecological protection zone [49
]. In addition, a reduced likelihood of human activities in these places decreased tillage accessibility.
In this study, although part of the crucial determinants of reclaimed land utilization was identified using logistic regression, the mechanisms of utilization progress could not be comprehensively presented. Indeed, socioeconomic factors based on household surveys, such as rural income, the agricultural labor intensity, the age and education of farmers, and industrial structure [50
], also have impacts on land use changes. These variables were not considered in our study because individual-level data were not available. Further research is necessary to consider more potential determinants, including household individual characteristics and economic factors at the multilevel, and to employ more regression techniques to improve model performance.
4.3. Policy Implications
The low utilization efficiency of reclaimed land in the study area may reflect some problems during the execution of the ALRB policy in China. The hidden reason is the conflict between the central control and local interests. The purpose of China’s central government proposed the ALRB policy is to maintain the total amount of arable land and to ensure food security by reclaiming the same area of land to replenish arable land losses caused by urbanization. While local governments have limited incentives to preserve natural resources [52
], they rely on the conversion of arable land to construction use to attract investment, fuel fiscal revenue, and achieve fast economic development [53
]. Therefore, local governments continue to expropriate arable lands near cities for urbanization on a large scale, including many high-quality lands [8
], and to seek replacements in border and less developed areas to meet the mandatory requirement, regardless of the location of reclaimed lands and regardless of whether they will be utilized. The undeveloped areas may even be willing to shoulder this burden because this reclamation involves financial compensation [4
]. Consequently, as shown in the study area, land reclamation projects have resulted in a large number of marginal, degraded, and isolated reclaimed arable lands. These lands were generally characterized by low utilization efficiency because of their unfavorable growing conditions, high opportunity costs, and low production income, damaging farmers’ willingness to cultivate them. Reclaiming more of these marginal lands can only cause more useless lands and aggravate environmental degradation. In fact, this phenomenon not only was found in the study area but also is prevalent throughout China, as demonstrated in the study by Lichtenberg et al. [54
The central government of China had realized the serious agricultural and environmental consequences of unqualified land reclamation under the ALRB policy, and proposed that the occupied paddy field must be supplemented by the same area of paddy field to emphasize the quality of reclaimed land. And we suggest that the central and provincial governments should strengthen the supervision of reclaimed land utilization. It is necessary to carry out scientific and reasonable land reclamation planning in consideration of the driving factors of land utilization. In this study, we found that neighborhood variables, especially Pct_forest and Adj_forest, had a crucial influence on land utilization in Wenzhou. Therefore, land reclamation projects should avoid agriculturally less favorable mountainous areas surrounded by forests and should be implemented in close proximity to other arable lands and rural residential areas. And land reclamation must be prohibited in ecological protection zones to ensure the natural restoration of vegetation in the region. In addition, compared to compensation for the arable land quantity, measures to improve arable land quality and productivity are better suited to promoting food security. Promoting land consolidation by reducing limitations such as those on building irrigation, cultivating soil fertility, and combining small farm plots to produce high-quality arable land, is a viable solution. Although this study was conducted only in Wenzhou, the methodological framework can be also applicable to other areas and countries when analyzing with the researches about land utilization and abandonment.
This study characterized the utilization patterns of reclaimed arable lands in Wenzhou, China. It was found that 8534.91 ha of arable land was reclaimed (from other land use types) between 2008 and 2014; however, until 2016, only 37.04% of the total area was under cultivation, and other lands were still bare or had been covered by grasses and trees. Therefore, knowledge about the drivers of reclaimed arable land cultivation is critical to understanding the utilization mechanism. In this study, we assessed the determinants of geo-physical, proximity, and neighborhood variables using logistic regression at the parcel level. The results revealed that reclaimed land cultivation was strongly correlated with the land use of adjacent or neighboring parcels. The degree of adjacency to surrounding arable parcels had a positive influence on land utilization, and the probability of being cultivated decreased with the increase in the degree of adjacency to forests and surrounding forest areas. In addition, elevation was a negative determinant, and soil fertility had a positive effect on land cultivation. Good accessibility to rural residential areas promoted the cultivation of reclaimed lands. Moreover, parcels located in an ecological protection zone had a lower probability of cultivation. These findings support the hypothesis that land utilization occurred where the cultivation costs were low and the potential productivity was high. We conclude that there has been a low degree of utilization of reclaimed land in Wenzhou, wasting resources and possibly having negative impacts on the environment. Land reclamation was more likely to be a mandatory task for local governments under the ALRB policy, decreasing the effectiveness of this policy. Thus, we suggest that reasonable land reclamation planning is needed that accounts for the driving factors of land utilization and the central and provincial governments should strengthen the supervision of reclaimed land utilization. Our study extends the understanding of the mechanism of reclaimed arable land utilization in China and is therefore a useful resource for land use planners to help them identify the most suitable land reclamation areas and to ensure agricultural and environmental safety.