SOILS FERTILIZERS. 219 



varying, however, with the character of the soil. It is suggested that dialysis 

 may prove a useful method of studying the available plant food in soils. By 

 the use of antiseptics in the soil samiiles experimented with it was shown that 

 the dialyzable plant food obtained was not due to the solvent action of micro- 

 organisms in the soil. 



The analysis of the soil by cultivated plants, A. Proost {Atti 6. Cong. In- 

 termix. L'him. AmA., 4 (1906), pp. '^5'^-.'^o^). — This is mainly a plea for more 

 thorougii study of the physics of plant growth and of the relation of natural 

 flora to the physical properties of the soil. 



A simple method of testing the manurial wants of soils (Dept. Agr. Ben- 

 gal, Quart. Jour., 1 {IVOS), No. 3, pp. I'lO-l'iS, fig. i).— A simple arrangement 

 of 8 plats, each 10 yds. square, for testing the need of soils for potash, nitrogen, 

 and phosphoric acid singly and combined is described. 



Testing soils for fertilizer needs, F. W. Taylor {New Hampshire Sta. Circ. 

 2, pp. 2). — A simple method of making fertilizer tests is briefly described. 



The results of practical fertilizer experiments, P. Wagner (Chcm. Ztg., 32 

 (1908), No. 19, pp. 233, 2J-'/). — The author summarizes the results of 6 years' 

 cooperative experiments with fertilizers carried out under the auspices of the 

 German Agricultural Society by the agricultural experiment stations of the 

 German Empire and reported from time to time in bulletins of the society 

 (E. S. R., 19, p. 925). It is stated that these experiments have demonstrated, 

 among other things, the proper method of fertilizing grapes, the beneficial effect 

 of potash fertilizers on tobacco, the exhaustion of soil potash by meadow grasses 

 and the beneficial effect of phosphatic and nitrogenous fertilizers on grasses, the 

 determination of the soils and crops on which potash salts rich in chlorin can 

 be used, the resistance of sugar beets to large amounts of chlorids, the special 

 need of potatoes and barley for potash and of leguminous plants for phosphoric 

 acid, and the more rational handling and use of manure. 



These experiments have also demonstrated the important fact that all of the 

 factors of production, including soil preparation, selection of varieties, amount 

 of seed, methods of planting, etc., must work together if the optimum production 

 is to be obtained. With an optimum of all these factors the yield may be in- 

 creased in the case of rye S90 to 1..500 lbs. per acre, with barley 980 to 1,600 

 lbs. per acre, with oats 1.100 to 1,800 lbs. per acre, and with rye on the poorest 

 land, 440 to 1,100 lbs. per acre. 



While fertilizing is not the only factor of production it is one of the most 

 important, but the profit from the use of fertilizers depends largely upon the 

 condition of the fertilizer market. The supply of phosphatic and potassie 

 fertilizers is abundant. The future supply of niti-ogenous fertilizers is more 

 uncertain. The author attaches great importance to the utilization of processes 

 of fixation and assimilation of atmospheric nitrogen by means of micro-organ- 

 isms and also to artificial processes of preparing nitrogen compounds from 

 atmositheric nitrogen. The latter he considers the most important question 

 affecting the fertilizer market at the present time. 



Increase and decrease of nitrogen in the soil by manuring {Armstrong Col., 

 Neivcastle-upon-Tyne. Agr. Dei)t. Bui. 7, pp. 30-32). — The results of fertilizer 

 experiments during a series of years on hay land are briefly referred to as show- 

 ing that " the judicious application of phosphatic manures, with the addition of 

 Iiotash manures if needed, is the most economical method of supplying nitrogen 

 to the soil, this being taken indirectly from the air by means of the root nodules 

 of clover plants; and further that the continued application of active nitrogenous 

 manures will ultimately greatly impoverish the soil in nitrogen." 



