Decomposition and nutrient release from Crotalaria spectabilis with glyphosate application

Abstract

Legumes used as green manure provide essential chemical elements to the soil through their biomass decomposition. However, nutrient availability may be significantly affected by herbicide application such as glyphosate. Thus, we evaluated the decomposition and nutrients release from the shoot dry phytomass and the root system of Crotalaria spectabilis with and without glyphosate application. After 90 days of C. spectabilis cultivation, the shoot and the root system were collected to determine the remaining phytomass. The analysis of variance for the remaining dry mass indicated the two-way interaction between herbicide and age was significant (P <0.0001). For most elements being released, the two-way interaction was significant. The remaining dry mass that received herbicide presented greater mineralization and faster reduction for most of the elements, resulting in the considerable nitrogen and phosphorus loss compared to the material without the herbicide, concluding that their decomposition was affected by the glyphosate application.

Keywords

• legume
• green manure
• herbicide
• mineralization