Abstract:

Concerning the issue of soil quality decline caused by excessive use of chemical fertilizers, and to provide scientific fertilization reference for corn cultivation and soil improvement in this region, this study explored the effects of reducing chemical fertilizers with applying mineral biochar on soil properties and corn yields in the Yellow River floodplain area. In order to study their effects on corn yield and soil properties, different chemical fertilizer reduction combined with mineral biochar treatments were set in this study, including conventional fertilization (F1, applying diammonium phosphate 300 kg/hm²), reducing 12.5% fertilizer with 75 kg/hm² mineral biochar (F2), reducing 25% fertilizer with 150 kg/hm² mineral biochar (F3), reducing 37.5% fertilizer with 300 kg/hm² mineral biochar (F4), and reducing 50% fertilizer with 600 kg/hm² mineral biochar (F5). The results indicated that the application of mineral biochar in the 0-20 cm soil layer enhanced nitrogen uptake by crops, effectively stabilized soil potassium levels, and increased soil phosphorus content. Compared to F1, the combined application of fertilizer and mineral biochar could significantly improve the corn yields by 1.48%-12.61%. Especially, when the application rates were 262.5 kg/hm² of diammonium phosphate and 75.0 kg/hm² of mineral biochar, corn yields and economic benefits reached their maximum. These findings demonstrated that replacing chemical fertilizer with mineral biochar could improve soil properties and ensure corn yields.

Key words: mineral biochar, reducing fertilizer, soil properties, corn, yield, economic benefits