Effects Of Glyphosate Application on Soil Ecological Health After Continuous Planting of Transgenic Glyphosate-Resistant Soybeans in Harbin, Northeast China

In modern agriculture, appropriate use of transgenic glyphosate-resistant soybeans are considered to be a key measure contributing to high yield and sufficient supply, in the process of which glyphosate is unavoidable. However, understanding of the impact on soil environmental health and the linkage between soil indexes is remarkably limited. This study conducted a 28-day field trial to explore the underlying effects and correlation of three glyphosate spraying does 1.2 (L), 2.4 (M), 3.6 (H) kga.i./hm2, transgenic (T) or recipient soybean (R) planting history on soil property components, nutrient regime and enzyme activities at the transgenic experimental station of Northeast Agricultural University - Harbin in Heilongjiang, China. Specifically, results concluded that soil alkali-hydrolyzable nitrogen (AN), available phosphorus (AP) content increased significantly, while cellulase and urease activities were reduced with passage of application time in the seven trial strategies. The concentration of glyphosate had no significant effect on soil moisture. Correlation analysis further showed that glyphosate dose was a significant driving factor for soil bulk density (BD), pH, organic matter (SOM), cellulase, urease and had a significant inverse relationship with soil phosphatase and catalase activities. The highest soil available potassium (AK) was obtained in group RSL across 28 days. The responses of enzyme activities suggested that transgenic glyphosate-resistant soybeans were effectively conducive and favorable to soil urease and phosphatase, but not soil catalase activities. Furthermore, transgenic glyphosate-resistant soybeans seemed to have the potential for changing soil structure and enhancing the variations in correlation between soil factors rather than recipient soybeans. These findings highlighted the importance and provided initial insights on safe release of glyphosate-resistant soybeans and glyphosate.

Keywords: Transgenic glyphosate-resistant soybeans; Glyphosate; Soil; Properties and nutrients; Enzyme activities; Correlation analysis