FIELD CEOPS. 329 



adversdy. The shortest roots were produced by the ammonium and potash 

 compounds. The root lengths of serradella were injuriously affected by chlorids 

 and nitrates, all the potash compounds, and ammonium sulphate, while sodium 

 phosphate and magnesium phosphate produced a favorable growth. With rape 

 the sulphates, phosphates, and carbonates produced the longest roots, and the 

 chlorids of potash, calcium, and ammonium the shortest, 

 k The influences of each fertilizing salt upon the development of the above- 

 ground parts are noted as follows : With rye, potassium and ammonium salts 

 worked the best, and sodium the poorest of the bases, while the carbonates and 

 phosphates produced the best and the chlorids the poorest results of the acid 

 compounds. With oats the greatest weights were obtained with ammonium 

 sulphat^ and phosphate, and the lightest weights wer*^ made with chlorids and 

 sulphates, with the exception of ammonium sulphate With barley, ammonium 

 sulphate produced the best growth, followed by sodium phosphate, while the 

 reverse influence was observed with the sulphates of s»d{um and magnesiimi 

 and the chlorids of magnesium and calcium. When beets were fertilized with 

 nitrates the growth was the greatest, but the least with the carbonates. Sodium 

 showed the best growth of the bases and calcium the poorest. With peas, 

 potash and magnesium salts made the best growths, while ammonium salts, 

 with the exception of sulphate of ammonia, produced the iworest. With kidney 

 beans the carbonates gave the best results and the chlorids the poorest of the 

 acids, while of the bases, potash and sodium compounds were the best and those 

 of magnesium the poorest, especially n^gnesium sulphate. With red clover, the 

 growth was unfavorably influenced by the chlorids and nitrates, with the excep- 

 tion of ammonium nitrate. The greatest amount of growth was produced with 

 the alsike clover when fertilized with phosphates; chlorids and nitrates proved 

 injurious. Alfalfa was favorably influenced only by potassium sulphate, potas- 

 sium carbonate, and sodium carbonate, while all other fertilizers had an in- 

 jurious effect, especially the ammonium compounds. Sodium phosphate and 

 calcium phosphate had a favorable effect on the growth of lupines, while am- 

 monium phosphate did not. "xhe chlorids and nitrates were unfavorable to the 

 growth of serradella, while the sulphates, carbonates, and phosphates were not. 

 Rape growth was greatly favored by potassium nitrate, and injured by chlorids 

 and all of the ammonium salts, especially ammonium sulphate. 



On the sig-niflcance of variety tests, C. Baeus (Science, n. ser., 86 (1912), 

 Vo. 928, pp. 81SS20). — This article is a discussion of the value of variety tests 

 as carried out and recorded by experiment stations. It is pointed out that 

 2 kinds of influences determine observed yield, viz, the innate capacity of the 

 variety and the conditions of growth to which it is exposed. The author sug- 

 gests that a concerted and systematic effort be made on the part of those inter- 

 ested in agricultural science to put this important problem on a sound basis 

 biologically and statistically, and presents tabular data showing the deviation 

 of yields of varieties from the yearly means and from their own means in 

 different years. 



Deep cultivation, R. Dumont (La Culture Profonde. Paris [1912], pp. 104, 

 figs. SS). — This book describes the different methods that may be employed 

 in plowing, subsoiling, and surface cultivation, giving costs of the various 

 operations and the seasons at which they should be performed. The author 

 advocates greater depth of plowing, and describes systems in practice on many 

 farms in France. 



Seeing the light at Anderson, W. A. Du Put (Country Gent., 78 (1918), No. 

 16, pp. 623, 62-'i, figs. 4). — This article describes methods of increasing soil 

 productivity used on a southern farm. Chiefly by deep plowing, good seeding, 

 green manuring, and rotation, the yields were increased from 12 bu. of com 



