Abstract:

To reveal the spatial differentiation patterns of yield ratios (PIR, PDR, IDR) among different cultivated land types (paddy field, irrigated land, dryland) for winter wheat and summer maize in Henan, the paper analyzed their coupling mechanism with cultivated land grade and terrain conditions, so as to provide a scientific basis for improving cultivated land irrigation use efficiency and optimizing cultivated land resources management. Based on the cultivated land grade database and township-level grain yield data (2031 towns for winter wheat, 2000 towns for summer maize) of Henan, 8 grading factor indicator zones (excluding the Huainan hilly and mountainous region) were selected as the study objects. The yield ratios were calculated using the area-weighted method. The correlation between cultivated land grade and IDR was fitted using trend analysis, and the spatial differentiation characteristics of IDR were interpreted with terrain classification. The results showed that: (1) at the indicator zone level, the volatility of yield ratios for both winter wheat and summer maize followed the pattern: IDR>PIR>PDR. The IDR showed the largest difference (0.55 for winter wheat and 0.48 for summer maize), indicating that the yield difference between irrigated land and dryland was most significantly affected by regional conditions; (2) at the provincial level, the regional differences in yield ratios were reduced and the patterns were weakened due to the area-weighted average neutralizing regional heterogeneity; (3) a positive correlation was found between cultivated land grade and IDR (the better the cultivated land quality, the larger the IDR). The sensitivity of winter wheat IDR to cultivated land quality (absolute slope value 0.030) was higher than that of summer maize (0.011); (4) under the same cultivated land grade, terrain ruggedness was positively correlated with IDR (IDR in mountainous and hilly areas was higher than that in plains and basins). The yield ratios among cultivated land types of winter wheat and summer maize in Henan exhibit the significant regional differences and scale dependence. Winter wheat shows a stronger dependence on irrigation conditions. It is suggested to prioritize enhancing the irrigation guarantee capacity for winter wheat on high-quality cultivated land; while for low-quality cultivated land, it requires synergistic improvements in both soil conditions and irrigation infrastructure to improve grain yield.

Key words: winter wheat, summer maize, cultivated land type, yield ratio, cultivated land grade, terrain