It is important to study the contributions of climate change and human activities to spatial-temporal changes of cropland in the fields of climate change and land use change. Relationships between spatial-temporal cropland changes and driving forces were studied at qualitative aspects in most of the previous researches. However, the quantitative assessments of the contributions of climate change and human activities to spatial-temporal changes of cropland need to be explored for a better understanding of the dynamics of land use changes. We systematically reviewed the methods of identifying contributions of climate change and human activities to temporal-spatial cropland changes at quantitative aspects, e.g. model analysis, mathematical statistical method, framework analysis, index assessment and difference comparison. The progresses of the previous researches on quantitative evaluation of the contributions were introduced. However, there were four defects in assessing the contributions of climate change and human activities to spatial-temporal cropland changes. For example, the methods were lack of comprehensiveness, and the data need to be more accurate and abundant. Moreover, the scale was single and the explanations were biased. Meanwhile, we concluded a clue about quantitative approaches to assess the contributions from the synthetical aspect to specific driving forces. Besides, the solutions of the future researches on data, scale and explanation were proposed.

Reconstructing the spatial data of historical LUCC could fill the gap between modern remote sensing interpretation results and long-term LUCC change analysis, and promote the study of spatiotemporal dynamics of land use and its impacts on climate and ecology. The current studies has obtained certain achievements and revealed the spatial pattern of historical LUCC to some extent. However, the results were normally in the form of single land use type and low spatial resolution. Thus, this study targeted to propose an integrated method of land use reconstruction with relatively high spatial resolution. We set 1820 as the time section and took the administrative boundary of contemporary Jiangsu Province as the study area. Supported by historical documentary records, historical geography research results, modern statistical data and natural environmental data, we divided the land use types into cropland, settlement (including urban land and rural residential land), water body and other lands (including forest, grassland and unused land). Considering the characteristics of regional natural resources and socioeconomic conditions, theoretical hypotheses were proposed to obtain the areas of cropland, urban land and rural residential land at prefectural level. Based on the modern land use pattern, from the perspective of man-land relationship, the land use map of Jiangsu Province in 1820 with a spatial grid of 100 m×100 m was established by administrative seat proximity analysis, integrated suitability indices analysis and so on. Then, statistics of different geographical divisions and comparative analysis of data in sub-regions were used respectively to analyze and validate the results indirectly. The results showed that: (1) In 1820, the area of cropland, urban land, rural residential land, water body and other lands of Jiangsu Province accounted for 48.49%, 4.46%, 0.16%, 15.03% and 31.86% of the total study area respectively. (2) The land use pattern in Jiangsu Province has general features of higher cultivation rate and lower construction rate. Meanwhile, affected by the discrepant population distribution, topography and drainage density, land use in different geographical divisions varied significantly. (3) The proportion of the area of residential land and cropland at county level occupying the correspondent city level in 1820 and 1985 showed a significant positive linear correlation. Therefore, the results of this study had certain reasonability and could provide methodological references for related historical LUCC reconstruction.