# Mapping Abandoned Cultivated Land in China: Implications for Grain Yield Improvement
## 4 Discussion and Implications
Other perspectives hold that cultivated land abandonment is a good opportunity to promote natural ecosystem restoration and biodiversity protection [67; 68; 69]. Therefore, in the future, we should focus on research on the environmental effects and regional differences of cultivated land abandonment to provide a scientific basis for formulating reasonable and effective measures of land abandonment. In China, under the influence of the land property rights system, cultivated land abandonment has been the rational choice for farmers to cope with the dilemma between increasing agricultural production costs and decreasing agricultural income. Since the randomness and instantaneity of cultivated land abandonment, the abandoned cultivated land cannot be taken back by local governments. Therefore, we should coordinate the allocation of policy tools such as fallowing, land conversion, land transfer, and high cultivated land construction standards and subsidies; implement differentiated land use policies; and optimize the spatial pattern of cultivated land use. For the abandonment of cultivated land in agricultural areas, it is necessary to increase the intensity of land conversion and actively carry out the construction of high basic cultivated land standards to ensure the productive functioning of cultivated land. For the abandonment of cultivated land in economically developed areas, we should develop multifunctional agriculture according to the trend and actively explore the characteristic agricultural industry by adjusting the planting structure to prevent the cultivated land from becoming idle and abandoned. For the abandonment of cultivated land in complex agroforestry areas, feasible policies or plans for returning the cultivated land to forest/grass should be formulated promptly to optimize the structure of land use and promote the sustainable use of cultivated land resources in ecologically fragile areas. In spite of the rich literature dealing with the problem of cultivated land abandonment in China, there was no comprehensive nationwide study that would include the spatial distribution of this phenomenon, in particular the impacts on grain yield. This paper used land use change survey data and national geo-information survey data to identify the distribution of abandoned cultivated land in China to ensure the full coverage of the data. More importantly, in addition to mapping spatial patterns of abandoned cultivated land based on GIS [70; 71; 72; 73], some analyses and calculations of abandoned cultivated land and its impacts on grain yield were all conducted in the R platform [17; 61], using the package data.table (v1.14.6), dplyr (v1.0.10), and raster (v3.6-13). It can be regarded as a more integrated analysis tool to better reflect the actual distribution of abandoned land more accurately and fill the gap in the current research scales and data. The implications obtained from the results could be used in strategic planning to help policy-makers achieve sustainable cultivated land use management. While this study proposed a new idea and an effective methodology for mapping abandoned cultivated land in China, there are several limitations and uncertainties: (1) The qualitative analysis on drivers of cultivated land abandonment still needs to be further discussed. It is more suitable for quantitative analysis in the future study. Such an exploration would lead to a much more holistic understanding of cultivated land abandonment. (2) There is no explicit identification method of cultivated land abandonment in current studies. In this paper, we defined it as the cultivated land that has remained dormant for a period of over two consecutive years, according to the Land Administration Law of the People's Republic of China. Therefore, we used a three-year period of land use data to identify the cultivated land abandonment. However, for some regions, this period may be too short to reliably analyze abandonment rates.