Soil organic matter (SOM) content is one of the most important indicators of soil quality and hence the productive capacity of soils. Northeast China (NEC) is the most important region in grain production in China. In this study, we assessed the spatiotemporal change of cropland SOM content in NEC using sampling data of 2005 and survey data of 1985. We also analysed the driving forces behind the SOM content change. Our results showed that SOM content decreased in 39% of all the cropland in NEC, while increase in SOM content was only detected on 16% of the cropland. SOM remained unchanged in nearly half (i.e. 45%) of the cropland. Our results also revealed that cropping intensity and fertilizer application were the two most important factors driving SOM change. Overall, results from this research provided novel details of the spatiotemporal patterns of cropland SOM content change in NEC which was not revealed in earlier assessments. The datasets presented here can be used not only as baselines for the calibration of process-based carbon budget models, but also to identify regional soil quality hotspots and to guide spatial-explicit soil management practices.

In this paper, an integrated indicator-based system is established to map the suitability of spring soybean cultivation in northeast China. The indicator system incorporates both biophysical and socioeconomic factors, including the effects of temperature, precipitation, and sunshine on the individual development stages of the spring soybean life cycle. Spatial estimates of crop suitability derived using this indicator system are also compared with spring soybean planting areas to identify locations where there is scope for structural adjustment in soybean farming. Results of this study indicate that northeast China is moderately suited to spring soybean cultivation. Areas classified as suitable, moderately suitable, and unsuitable for soybean cultivation, respectively, occupy approximately 9.09 3 10 4 , 11.45 3 10 4 , and 7.99 3 10 4 km 2 , accounting for 11.5%, 10.11%, and 14.49% of the total area of northeast China. The Songnen and Sanjiang Plains are identified as the most and least suitable places, respectively, for spring soybean growth. A comparative analysis indicates that the suitable, moderately suitable, and unsuitable areas account for 24.78%, 46.30%, and 28.92%, respectively, of the total area presently under soybean cultivation. The analysis suggests that soybean cultivation in Heilongjiang Province is generally unfavorable, with equivalent percentages of 15.39%, 51.70%, and 32.91%. Results suggest that agricultural structural adjustment may be required to encourage farmers to grow spring soybeans. It is anticipated that this study will provide a basis for follow-up studies on crop cultivation suitability.

No abstract

No abstract

No abstract

No abstract

No abstract

No abstract