Land use change driven by diet, globalization, and technology advancement have greatly influenced agricultural production and environment in the mollisols region of China, with a marked impact on the depletion of soil organic matter, a signature property of mollisols. Here we report findings on soil organic carbon (SOC) change in three different cropping systems (soybean, soybean/maize, corn) in Northeast China during a 10-year time span. The results indicated that the decline rate of SOC in recent ten years (0.27 g kg−1 yr−1) has slowed down considerably compared to previous decades (1.12 g kg−1 yr−1). Crop system conversion from soybean monocropping to corn monocropping or break system was the critical factor for SOC change, and the background SOC was the second influence factor. When approaching a SOC turning point, conversion from low carbon input crop system (soybeans monocropping) to high carbon input crop system helped slow down the SOC decline (break crop) or even improve SOC (corn monocropping) in mollisols regions. This result implied that imported soybean has brought benefit for Northeast China. But for sustainable goal in China’s mollisols region, straw returning, optimized nitrogen fertilization and no tillage are all necessary whatever in continues maize or rotation system.
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机译：饮食，全球化和技术进步所驱动的土地利用变化极大地影响了中国糖蜜地区的农业生产和环境，对土壤有机质的消耗产生了显着影响。在这里，我们报告了十年间中国东北三种不同种植系统（大豆，大豆/玉米，玉米）土壤有机碳（SOC）变化的发现。结果表明，最近十年（0.27 g ratekg −1 yr −1 ）SOC的下降速度与前几十年（1.12 g kg < sup> -1 yr -1 ）。从大豆单作到玉米单作或中断系统的作物系统转化是SOC变化的关键因素，背景SOC是第二个影响因素。当接近SOC拐点时，从低碳输入作物系统（大豆单作）向高碳输入作物系统的转换有助于减缓SOC的下降（中断作物），甚至改善了糖蜜地区的SOC（玉米单作）。这一结果表明，进口大豆为中国东北带来了利益。但是，为了实现中国糖浆地区的可持续目标，无论是在连续玉米还是轮作系统中，秸秆还田，优化氮肥和无需耕种都是必需的。
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