Sulfur fertilization contribute to China’s food security: A meta-analysis

Sulfur (S) deficiency is an increasingly significant constraint to plant growth all over the world. Application of S fertilizer becomes an inevitable approach to alleviate S deficiency and improve crop yield. However, there is still lack of quantitative assessment of yield potential of crops fertilized with S fertilizer. In this study, an integrated meta-analysis with 181 studies with 1162 comparisons was conducted to evaluate the effect of S fertilization on crop yield in China. The results showed that S fertilization could improve crop yield by an average of 8.2 %. The increase in yield of sugarcane (11.2 %), tea (10.5 %), oil crops (9.9 %) and vegetables (9.1 %) were higher than that of cereal (7.4 %). The effect of S fertilization on crop yield was 9.5 % when soil pH was less than 6. Under soil S deficiency (≤16 mg kg⁻¹), crop yield improved 9.6 %, more than 30 % of yield in the adequate S soil (more than 30 mg kg⁻¹). Among S fertilizer types, ammonium sulfate had the bigger yield-increasing effect with 10.3 % than other S fertilizers. The yield effect of S fertilizers was correlated with soil organic matter, with 10.8 % yield under the low soil organic matter (≤12 g kg⁻¹), and 6.7 % yield increase under high soil organic matter (≥20 g kg⁻¹). Additionally, it resulted in a higher yield of 7.7 % under high precipitation (＞1000 mm) compared to a 5.4 % yield increase under low precipitation (≤1000 mm). This study demonstrates that S fertilization significantly improve crop yield, and provided great potentials for integrated S management based on the soil-crop-climate conditions for higher crop yield without additional NPK input in China.