Estimation of nitrogen and sulfur mineralization in soils amended with crop residues contributing to nitrogen and sulfur nutrition of crops in the North Central U.S

ABSTRACT

Predicting nitrogen (N) and sulfur (S) mineralization of crop residues from the preceding crop might be a useful tool for forecasting soil N and S availability. Two soils from eastern North Dakota and three crop residues – corn, spring wheat, and soybean were used in an 8-week incubation study to estimate N and S mineralization from crop residues. The cumulative N and S mineralized were fit to a first-order kinetic model. Cumulative N mineralized ranged between 0.34 and 2.15 mg kg⁻¹ and 0.45 to 3.41 mg kg⁻¹ for the Glyndon and Fargo soils, respectively. Un-amended soils showed higher N mineralization than residue treated soils. For S, the highest mineralization occurred in un-amended Glyndon soil and in spring wheat-amended Fargo soil. This study indicates that crop residue additions can have a negative impact on plant available nutrients due to immobilization of N and S during the time when crops need the nutrients most.

KEYWORDS:

• Crop residues
• Immobilization
• Mineralization
• Nitrogen
• Sulfur