Estimating Potential Nitrogen Mineralisation Using the Solvita Soil Respiration System

Abstract

Nitrogen (N) mineralisation contributes considerably to crop growth in fertilized and unfertilized fields. It is useful to be able to assess potential N mineralisation to increase fertilizer application efficiency, prevent excessive N runoff, and improve environmental system models. The microbes present in soil mineralize N based on many factors, including soil temperature and moisture, tillage, and levels of organic C and N. The measurement of soil’s ability to mineralize N is considered a good indicator of soil quality. Many methods have been developed to estimate N mineralisation in the laboratory and field. The 7-day anaerobic N mineralisation method developed in the 1960’s is considered reliable and is often used to compare new N-mineralisation testing methods. This study examines the use of soil CO 2 evolution as determined using the Solvita Soil Respiration System (Solvita) for estimating N mineralisation by comparing it directly to the anaerobic N mineralisation test. Measured CO 2 using Solvita was strongly correlated with anaerobic N mineralisation (r 2 = 0.82). Results indicate that the Solvita Soil Respiration System can be used to rapidly assess soil respiration and relative N mineralisation potential in any given soil and is considerably faster and easier to perform in a laboratory setting than the anaerobic N mineralisation test.