78 



and failed to accumulate nitrates. There appeared to be no relationship be- 

 tween the ability of a soil to nitrify the two types of media. 



The Effect of Sand and Lime on Nitrification. 1 



The stimulation which lime offers nitrification is universally accepted as 

 one of the most far reaching effects which it exerts on soil fertility. This 

 fact has been shown by so many experiments that it no longer provokes 

 intelligent controversy. Furthermore one phase of the beneficial activity 

 usually ascribed to lime is a physical influence which it exerts on soils and 

 which renders them open and friable, more easily penetrated by air, condi- 

 tions which presumably favor nitrification. It is to be expected, therefore, 

 that, other conditions being equal, soils of light open texture would have a 

 higher nitrifying power than compact heavy soils. Working with this idea 

 in view, an effort has been made in a few instances 2 to promote nitrification 

 in clay soils by the addition of sand in various proportions. Comparative 

 experiments with sand and lime are of interest, since each contributes some- 

 thing to the process of nitrification as influenced by the physical condition 

 of the soil. 



During the summer of 1914 an experiment was carried on at this station 

 duplicating somewhat the work previously reported but introducing one 

 new feature an observation on the effect of adding one-fourth clay to an 

 open sandy soil. These soil- types which have had extensive use here, were 

 employed in the work: Albemarle and Appomattox Chocolate, both heavy 

 clay soils, and Norfolk sandy loam, one of the light porous soils from Tide- 

 water Virginia. The experiment was arranged in the greenhouse, using two 

 gallon pots which received soil in the following order : 



The same quantity of soil was added to each pot and all brought to 18 

 percent moisture content. That the rate of nitrification might be measured 

 more strikingly, ammonium sulphate .1 percent was added to all pots. The 

 experiment received the usual greenhouse care, the moisture content of the 

 pots being kept uniform, and there was no condition which failed to in- 

 fluence all pots alike. At the end of the eight and twelve weeks, 500-gram 

 samples were taken for nitrate analyses which were made according to the 

 Iron-Zinc Reduction method. The results of the analyses from each pot 

 are given in Table I. 



1 Paper 39 fr-im the Laboratories of Plant Pathology and Bacteriology, Virginia Agr. Exp. Sta. 

 2 Reitmair: Zeitschr. f. d. Landw. Vers. Wesen in Osterreich 11, 1908, p. 215. 

 Fred, E. B. Va. Agr. Exp. Sta. Ann. Kept., 1911-12, p. 185. 



