Method for determination of the gross nitrogen-mineralization rate of a soil sample

Method for determining the gross N-mineralization rate of a soil sample, said method comprising the steps of

• i) determining the activity of a microbial enzyme of a functional ornithine acid cycle contained in said sample,
• ii) determining said gross N-mineralization rate of said soil sample by correlating said activity determined in step i) with said rate of gross N-mineralization on the basis of
• a) determining an activity of said enzyme contained in said sample,
• b) determining a rate of gross N-mineralization of said sample,
• c) generating corresponding values of said activity determined in step a) and said rate determined in step b), said corresponding values forming a correlatable relationship between said activity and said rate, and
• d) generating a correlation of said activity with said rate based on said corresponding values generated in step c).

Method of correlating the turn-over rate of urea to ammonium with the gross N-mineralization rate of a soil sample, said method comprising the steps of

• i) determining a urea turn-over rate of said sample,
• ii) determining a gross N-mineralization rate of said sample,
• iii) generating corresponding values of said urea turn-over rate determined in step i) and said gross N-mineralization rate determined in step ii), said corresponding values forming a correlatable relationship between said urea turn-over rate and said gross N-mineralization rate, and
• iv) establishing a correlation of said urea turn-over rate with said gross N-mineralization rate based on said corresponding values generated in step iii).