Plant-based assessment of inherent soil productivity and contributions to China's cereal crop yield increase since 1980.

PLoS One · 2013 · PMC3776784 · PMID 24058605

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an increasing trendno p-value reported

During the three decades since 1980, SOM concentration in surface layer of soils in most cereal-based cropping systems followed an increasing trend (Table S1 in File S1 ) [ 7 , 24 - 26 ].

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