Effect of Soil Mesh-size on the Estimation of Mineralizable Nitrogen in Soils

Abstract

IT is generally accepted that the most satisfactory methods now available for assessment of the potential ability of soils to provide nitrogen for crop growth are those involving estimation of the mineral nitrogen formed when soil is incubated under conditions that promote mineralization of soil nitrogen^1,2. Methods involving incubation under aerobic conditions at 28°–35° C for 2–4 weeks have been generally preferred, and numerous investigations of factors affecting the results obtained by these methods have been reported^1,2. However, very little attention has been given to the effect of soil mesh-size, and many workers have not considered it necessary to describe the method used to grind and sieve soil samples for estimation of mineralizable nitrogen by incubation techniques. Published work on the effect of mesh-size appears to be confined to rather limited investigations by Fitts³ and Hagin and Halevy⁴, which indicated that mesh-size is of minor importance. This conclusion is not supported by the work reported here.