SOILS FERTILIZEES. 621 



accumulate and form a mat on the soil so thick that the penetration of water 

 to the lower layers is seriously impeded." 



Live stock and soil fertility, C. E. Thorne (Penn. Dept. Agr. Bid. 26Jf 

 (1915), pp. 2S5-293). — Eighteen years' experiments at the Ohio Experiment 

 Station, comparing fresh and barnyard manure and manure reinforced with 

 acid phosphate or rock phosphate at the rate of 40 lbs. per ton of manure, are 

 reviewed. 



The results showed that when the manures were added at the rate of 8 tons 

 per acre to corn in a 3-year rotation of corn, wheat, and clover the fresh manure 

 gave better results than the barnyard manure. During the second year both 

 manures had a greater effect than during the first year. Of the phosphorus 

 carriers, the acid phosphate was superior to the rock phosphate, this being 

 more marked in the second than in the first year. 



Lime and commercial fertilizers in the maintenance of soil fertility, C. E. 

 Thorne (Pcnii. Dcpt. Agr. Bill. 264 (1915), pp. 173-1S1).—A review of field 

 fertilizer experiments at the Ohio Experiment Station on a sandy clay soil 

 using a 5-year rotation of corn, oats, wheat, and clover and timothy mixed, in 

 which lime was added at the rate of 1 ton per acre together with fertilizers 

 and manure, showed that " the lime alone materially increased the yield on the 

 unfertilized land, the gain from lime alone being nearly as great as that from 

 phosphorus alone in the corn crop and considerable greater in the hay crops. 

 When the liming supplemented the use of fertilizers and manure it maintained 

 in the grain crops practically the same additional increase over that produced 

 by the fertilizers that it had given on the unfertilized land, while in the clover 

 and timothy the liming produced nearly twice the increase on the fertilized 

 or manured land that it had on the unfertilized land. . . . These results show 

 the fundamental importance of lime in the maintenance of fertility because of 

 its great effect on the clover crop, but they also show that lime can not take 

 the place of other fertilizing elements, but can only perform its full service 

 when associated with phosphorus, potassium, and nitrogen." 



The manurlal situation and its difiiculties, J. Hendeick (Jour. Bd. Agr. 

 [London'], 22 (1915), No. 7, JW- 609-616).— In a review of the fertilizer situa- 

 tion in Great Britain it is stated that the most serious scarcity may be expected 

 in potash fertilizers, and that with reference to the other kinds of fertilizers 

 a greater difficulty will arise from want of labor and transportation facilities 

 than from want of raw material. 



The nitrogen problem in arid soils, C. B. Lipman (Proc. Nat. Acad. ScL, 1 

 (1915), No. 9, pp. .'(77-^80). — On the basis of investigations conducted at the 

 California Experiment Station it is stated that the most prominent cause of the 

 lack of available nitrogen in the arid soils of CaKfornia is a feeble nitrifying 

 power of the soil, which is attributed largely to lack of organic matter. Green 

 manuring and the use of barnyard manure and low-grade organic nitrogenous 

 fertilizers, such as steamed bone meal, cotton-seed meal, and sewage sludge, or 

 else ammonium sulphate, are recommended for such soils, together with the use 

 of a straw or manure mulch to prevent overheating of the soil and excessive 

 evaporation. 



A report by the author along similar lines has been previously noted (E. S. R., 

 33, p. 24; 34, p. 219). 



Pot experiments on the availability of nitrogen in mineral and organic 

 compounds, J. G. Lipman, H. C. McLean, A. W. Blair, and L. K. Wilkins 

 (New Jersey Stas. Bnl. 280 (19U), pp. 5-23, pi. i).— The substance of this 

 bulletin has been noted from the report of the stations for 1914 (E. S. R., 34, 

 p. 129, 132). 



