Soil Nutrient Changes in Black Soil of Northeastern China Under Long-Term Cultivation with Different Fertilizer Applications and Tillage Patterns: A Meta-Analysis

As one of the four major black soil distribution areas in the world, the black soil region in northeastern China has shown a trend of nutrient degradation under excessive development. Understanding its nutrient changes and the factors affecting them is of great significance to the sustainable development of black soil. Soil nutrient profiles are influenced by several anthropogenic management patterns, including fertilizer application methods and tillage practices. A comprehensive analysis of the influencing factors can help to understand the mechanisms of nutrient changes in black soil cropland. Therefore, using soil organic carbon (SOC) as a proxy for nutrients, this study applied a meta-analysis based on 1138 observations from 60 papers to reveal the effects of anthropogenic management practices (application of organic fertilizers (OF), straw back (SB), application of chemical fertilizers (CF) and conservational tillage (CT)) on soil nutrients. The results showed that the most of soil nutrients increased significantly under management model. The application of chemical fertilizers decreased soil pH by 4.55% and increased soil available phosphorus (AP) content by 112.14%. Compared to the conventional model, application of organic fertilizers significantly increased SOC content, total nitrogen (TN) content and microbial biomass carbon (MBC) content by, 16.75%, 20.10% and 31.15% (p < .05), respectively. The effect values of SOC content were positively correlated with those of most soil nutrient contents under different anthropogenic management. This study helps to understand the response of nutrient content of northeastern black soils to different anthropogenic management models and provides reasonable references for sustainable farming patterns.