Ammonia released on Treating Soils with N Sodium Hydroxide as a Possible Means of predicting the Nitrogen-supplying Power of Soils

Abstract

THE only reliable method at present available for estimating the potential nitrogen-supplying power to crops of the organic nitrogenous fraction of soils is the incubation procedure. In this, soils are incubated under optimum conditions of moisture and temperature for periods of two weeks or longer and the quantity of nitrogen mineralized taken as a measure of their nitrogen-supplying power. Many workers have shown good correlations between the amount of nitrogen mineralized during incubation and crop production. These results have been well summarized by Harmsen and van Schreven¹. The main drawbacks of the incubation method are the length of time required and the relative tediousness involved in extracting and determining mineralized nitrogen. A quicker method which also requires less manipulation is obviously desirable, particularly where large numbers of samples are being tested, such as in advisory work.