1916] AGRICULTURAL BOTANY. 221 



addition to complete fertilizer increased the yield of rape. The proteid nitrogen 

 and organic sulphur content of rape grown on soil treated with sulphates in 

 addition to dicalcium phosphate, potassium chlorid, and sodium nitrate has been 

 increased. The increased amount of sulphur assimilated by the rape crop, from 

 soil treated with sulphur in addition to pho.sphorus, potassium, and nitrogen, is 

 mostly combined as organic sulphur. The nonproteid nitrogen found in the 

 rape plant grown under the conditions of this experiment is in excess of the 

 proteid nitrogen. 



"On limed soil calcium and magnesium sulphate, in addition to phosphorus, 

 potassium, and nitrogen, increased the yield over that from similarly treated 

 plats receiving no sulphates. Potassium and ammonium sulphate on limed soil 

 also produced more rape than plats where potassium chlorid and sodium nitrate 

 furnished the potassium and nitrogen. Magnesium sulphate, where used with 

 complete fertilizer and calcium carbonate, produced more soy beans and millet 

 seed than calcium sulphate. 



" The use of sulphur and hydrogen sulphid in pot tests increased the acidity 

 of the soil. Pots so treated gave a greater weight of clover than the untreated 

 or limed pots. 



" Experimental data obtained by extracting mixtures of soil, sulphur, and 

 rock phosphate with 0.2 per cent hydrochloric acid indicate that oxidation of 

 sulphur has increased the solubility of the insoluble phosphorus." 



A list of 25 references to literature bearing on the subject is appended. 



The fertilizing' power and harnifulness of fertilizing' materials, A. Vrv'iEN 

 (Bui. Assoc. Chim. Sucr. et Distill., 32 {191.'f), No. 1-2, pp. 36-J^2; abs. in Chem. 

 Abs., 9 (1915), No. 21, p. 2962). — The author reviews work by himself and others 

 showing the toxic effect of dilfei'ent salts on plants, and gives the toxic dose 

 of each of 16 sodium, potassium, ammonium, and calcium salts for Bordeaux 

 wheat. It is pointed out that sugar beets may be grown on soils containing 

 amounts of salts which would be toxic to other crops, as the beets absorb the 

 salts and gradually remove the excess of mineral matter from the soil. Such 

 beets are said, however, to yield a sugar solution of low purity. 



Fertilizer registrations for 1916, C. S. Cathcabt (New Jersey Stas. Bui. 

 290 (1916), pp. 3-52).— This bulletin contains a list of 1,137 brands of fertilizers 

 and their guaranties, as registered in New Jersey for the year ending October 

 31, 1916. 



AGRICULTURAL BOTANY. 



An experim.ental study of the rest period in plants: Physiolog'ical changes 

 accompanying breaking of the rest period, W. L. Howard (Missouri Sta. 

 Research Bui. 21, pp. 3-72, figs. 10). — In continuation of the author's study on 

 the rest period of plants (E. S. R., 33, p. 520), a description is given of 

 physiological investigations conducted to secure information on the specific 

 effects produced by anesthetics and other agents employed in breaking the 

 rest period of woody plants. 



As a result of respiration and other studies, the conclusion is believed justi- 

 fied that the specific effect of all rest period breaking agents on dormant woody 

 tissue is the stimulation of the enzyms. The rest period is believed to begin 

 with the inhibition of enzyms by the accumulation of the products of their 

 work. This may take place in mid or late summer. In the fall an excess 

 supply of carbohydrates continues to be accumulated with the further inhibi- 

 tion of enzyms. This brings about the main or middle state of rest. Toward 

 the end of this period enzyms become more and more active, giving place to 

 the beginning of growth. The length of the rest period is said to vary greatly 

 54530°— No. 3—16 3 



