Quantitative assessment of the relationship between cultivated land quality grades and grain production capacity in the Huang-Huai-Hai region of north China

Objectives Cultivated land quality is the foundation of food security and high-quality agricultural development. Understanding the quantitative relationship between cultivated land quality and grain production capacity is significant for evaluating the regional grain production potential and supporting the national action of “increasing fifty million tons of grain”.

Methods A case study was conducted inHuang-Huai-Hai region, which was based on the survey and evaluation data of cultivated land quality in 2017. Taking secondary agricultural zones as evaluating units, we developed a functional model between cultivated land quality grades and grain production capacity per hectare. Combined with county-level cultivated land area data, the grain production capacity at the county scale in theHuang-Huai-Hai region was evaluated, and the model results were verified using actual statistical data.

Results The results showed a significant positive correlation between cultivated land quality grades and grain production capacity per hectare in theHuang-Huai-Hai region (R²>0.95). Spatial analysis showed that the grain production capacity per hectare was relatively high in the Hebei-Shandong-Henan low-lying plain agricultural zone, Yanshan-Taihang Mountain foothill plain agricultural zone, and Huang-Huai Plain agricultural zone, while it was lower in the Shandong Hilly agriculture and forestry zone. The rank of grain production capacity per hectare from high to low in the secondary agricultural zones was: the Hebei-Shandong-Henan low-lying plain agricultural zone 1.56×10⁴ kg/(hm²·a), the Huanghuai Plain agricultural zone 1.52×10⁴ kg/(hm²·a), the Yanshan-Taihang Mountain foothill plain agricultural zone 1.51×10⁴ kg/(hm²·a), and the Shandong Hilly agricultural and forestry zone 1.31×10⁴ kg/(hm²·a). The county-level production capacity evaluation based on cultivated land area data showed that the county-level grain production capacity presented a spatial distribution characteristic of high in the south and low in the north. After model adjustment, the estimated grain production capacity showed a strong statistical fit with actual grain production (R²>0.90). In the secondary agricultural zones, the Shandong Hilly agricultural and forestry zone exhibited the best fitting effect.

Conclusions The grain production capacity assessed by the quality of cultivated land can better reflect the grain production potential of the region after correction. The grain production capacity of the entireHuang-Huai-Hai region is 3.18×10¹¹ kg, and the grain production capacity per hectare is 1.49×10⁴ kg/(hm²·a).