SOILS — FERTILIZERS. 319 



witli sodium chlorid and sulphate, the former being present to some extent in 

 the form of crystals of pure salt which can be easily separated from the soil. 



The poverty of this sample in potash and phosphoric acid accords with 

 results of previous analyses of African soils, which show that the soils are as 

 a rule very poor in these constituents. The importance of the results as indi- 

 cating a source of supply of salt, which is generally scarce in Africa, is also 

 noted. 



The absorptive capacity of some Palatinate soils for different plant 

 nutrients, O. Engels {Landw.Jahrh. Baijern, 1 {1911), No. 9, pp. 689-706). — 

 Measurements were made of the absorptive powers of 5 soil types of the region 

 for solutions of superphosphate, potassium sulphate, ammonium sulphate, and 

 sodium nitrate during 4 hour, 1, 8, and 14 day periods. The author used per 

 100 gm. of the soil 200 cc. of the potassium sulphate and ammonium sulphate 

 solutions, containing respectively 0.5416 gm. potash and 0.408 gm. nitrogen. 

 The proportions of superphosphate and sodium nitrate used are not stated. 



The results of these studies show that there was practically no further absorp- 

 tion of potash and ammonia after 4 hours. Absorption of these substances, 

 as well as of phosphoric acid, increased with the lime, iron, and alumina con- 

 tents of the soil. There was no absorption with the sodium nitrate solution. 

 The absorption of phosphoric acid increased with the lapse of time, there being 

 in some cases an absorption for 14-day periods of 3 times that for the 4-hour 

 periods. After 4 weeks there was practically no increase in absorption of phos- 

 phoric acid except a small increase in case of a soil rich in lime. 



Investigations on the nitrogen economy of the soil, W. Schneidewind, 

 D. Meyer, and F. MiJNTEB {FiihUng's Landw. Ztg., 60 (1911), No. 22, pp. 

 780-791). — Determinations were made of the relative amounts of nitrogen in 

 fallow and id cropped soil plats for a period of 3 years, together with tests of 

 the influence of added straw, peat, and sugar on the assimilation of nitrogen by 

 the plants. The crops grown were turnips, oats, and potatoes during 1909, 1910, 

 and 1911, respectively. 



The results of the study show that in the fallow plats there was considerable 

 loss of nitrogen (85.5 lbs. i^er acre), mostly as nitrates in the drainage water 

 but probably also in the form of ammonia and free nitrogen. The loss in nitro- 

 gen was less in the cropped than in the fallow soil plats notwithstanding the 

 large amounts of nitrogen taken up by the plants. Including the nitrogen 

 assimilated by the plants, there was an average yearly gain in nitrogen of 29.5 

 lbs. per acre for the cropped plats. Straw and sugar, even when applied in the 

 fall, somewhat reduced nitrogen assimilation by the plants, but the total nitro- 

 gen content of the straw and sugar soil plats did not vary from that of the 

 unfertilized plats and from those fertilized with peat. 



Formation of nitrates in cultivated soil, A. Koch (Jour. Landw., 59 (1911), 

 No. 3, pp. 293-315; ahs. in Cliem. Zentbl., 1911, II, No. 15, p. ii70).— Determina- 

 tions of nitrates from time to time at different depths down to 80 cm. in soils 

 protected from leaching showed a slow but steady increase in nitrates, which, 

 however, was greater the first year than later. Improving aeration by adding 

 sand or loam increased the formation of nitrates. The nitrate content and the 

 nitrifying power declined with the depth, the former more rapidly than the total 

 nitrogen. 



In pot experiments in which ammonium sulphate was applied at the rate of 

 2 gm. per kilogram of soil, it was found that about one-half of the sulphate 

 applied in November was nitrified by the following March, thus showing quite 

 active nitrification during the winter months. There was, however, a consider- 

 able loss of the nitrogen of the sulphate in the process of oxidation to nitrates. 

 amounting in one case to 29 per cent. In soils to wnich ammonium sulphate 



