SOILS — FERTILIZERS. 217 



The determination of the fertilizer needs of soils by the aid of chemical 

 soil analysis, O. Lemmeemann (Landw. Vers. Stat., 83 (1914), A'o. 5-6, pp. 

 .345-358; abs. in- Zlschr. Angew. Chem., 27 {1914), No. 31, Referatenteil, p. 

 298). — The author is of the opinion that the available plant food in soils, and 

 consequently their fertilizer needs, ic not exactly indicated by the amount of 

 plant food soluble in water saturated with carbon dioxid according to the 

 Mitscherlich method of chemical soil analysis. He maintains that this is influ- 

 enced bj^ other factors such as organic acids, soil bacteria, climate, etc. 



The determination of the fertilizer needs of soils by the aid of chemical 

 soil analysis, E. A. Mitscherlich (Landw. Vers. Stat., 83 (1914), No. 5-6, pp. 

 401-408). — The author defends his views regarding the value of chemical analy- 

 sis of soils in determining the fertilizer needs of soils, but emphasizes the im- 

 portance of a plant physiological basis for all such analyses. 



Estimating- the fertilizer need of soil, E. A. Mitscherlich {FuhUng's 

 Landw. Ztg., 63 (1914), No. 3, pp. 75-78). — The author points out the inaccuracy 

 of Liebig's law of minimum as applied to the results of fertilizer experiments, 

 in that the increase in crops due to fertilizing is not an exact indication of the 

 fertilizer need of soils owing to the fact that all other environmental factors 

 exert an influence on the increase in crop and must be kept constant in order 

 to determine the effect of varying amounts of a particular element. To obtain 

 constant factors of environment in pot experiments the different soils were 

 kept at their full water capacity during the entire vegetation period. Of 8 

 samples of each kind of soil, 4 were treated with a 1 to 2 per cent nutritive 

 solution without phosphoric acid, and 4 with a 1 to 2 per cent nutritive so- 

 lution containing phosphoric acid. The success was very limited, owing to the 

 tenacity of the soils, but where successful the phosphoric acid deficiency was 

 indicated by the reddening of the oats plants, it being greater the deeper the 

 color. 



The behavior of common and improved varieties of plants toward artificial 

 fertilization, F. Mass (Kali, 7 (1913), p. 611; ahs. in Chem. Abs., 8 (1914), 

 No. 7, p. 1322). — "The experiments were carried out on stony ground which 

 was fertilized as follows : 0, 3, G, and S kg. superphosphate; 0. 1, *, 3, and 4 kg. 

 potassium salts ; 1, 0, 2, and 3 kg. Chile saltpeter per 100 square meters. Four 

 varieties of barley, 3 of oats, and 2 of summer rye were used in the experiments. 

 The results show that on land that is wanting In plant food the common vari- 

 eties yield better crops, while with fertilized land the improved varieties are 

 more productive." 



Maintenance of soil fertility: Plans and summary tables (Ohio Sta. Circ. 

 144 (19^4)' PP- 63-97, fig. 1). — This is one of the annual statements on the sub- 

 ject (E. S. R., 29, p. 213), bringing the data for the experiments at Wooster 

 and Strongsville up to the end of 1913 and summarizing the results for 20 

 years (1894-1913) at Wooster and 19 years (1895-1913) at Strongsville. 



Soil fertility, G. Roberts (Kentucky St<i. Ext. Circ. 11, pp. i6).— This is a 

 popular discussion of the fertilizer requirements of crops and soils and of the 

 best methods of using fertilizers. Reference is made to an experiment which 

 indicated " that in beginning the restoration of a badly worn soil deficient in 

 phosphorus, it is best to use an application of acid phosphate in growing a 

 cowpea crop to be turned under with a liberal application of raw ground phos- 

 phate rock, to be followed with clover as soon as possible. Clover seems es- 

 pecially able to utilize the rock phosphate. The clover turned under, pastured, 

 or fed, and the manure returned, furnishes available phosphorus, as well as 

 nitrogen, for succeeding crops. On soils fairly well supplied with organic 

 matter, rock phosphate may be used to begin with." 



