The Use of Magnesium Fertilizer Can Improve the Nutrient Uptake, Yield, and Quality of Rice in Liaoning Province

In this study, the effects of the soil application and foliar spraying with magnesium fertilizers on rice yield and quality in Liaoning Province were investigated. Field experiments were conducted at Kaiyuan, Xinmin, and Dawa in 2022 and 2023. Magnesium fertilizers were used in the soil as magnesium sulfate monohydrate and silicon–magnesium fertilizer and on leaves was magnesium sulfate heptahydrate. The results showed that the application of 12 kg magnesium hm⁻² in the soil at the Kaiyuan site can significantly increase rice yield by 14.8% compared with sites without magnesium fertilizer. The use of silicon–magnesium fertilizer showed a more obvious yield increase of 22.2%. The application of 3 kg magnesium hm⁻² or 6 kg magnesium hm⁻² on the leaf surface increased the rice yield at Kaiyuan by 19.4% and 21.6% and at Xinmin by 17.8% and 5.4%, respectively. The yield increase was more significant under the optimal fertilization treatment compared with the conventional fertilization treatment. The application of magnesium fertilizer increased the magnesium, nitrogen, and phosphorus contents in rice shoots and the potassium and crude protein contents in rice grains. The effect of foliar spraying with magnesium fertilizers was more obvious than soil application. Therefore, the magnesium fertilizer used on the leaf surface plays an important role in improving rice yield and quality in rice-growing areas with relatively rich soil magnesium content. Magnesium fertilizer can compensate for the yield decrease caused by the reduced use of nitrogen and phosphorus fertilizers by promoting nitrogen and phosphorus absorption in rice. Conclusively, the application of magnesium fertilizer is a promising measure to improve rice production in Liaoning province under a reduced nitrogen and phosphate fertilizer background.