FERTILIZEES. 125 



The above changes did not occur when manure was added in amounts 

 usually employed in practice, or even when added in considerabl}^ larger 

 amounts than are usuall}^ applied, but only when excessive amounts 

 were used. When excessive amounts are not used the author claims 

 that the nitrates are not decomposed and the urine is nitrified. 



G-round bone compared -with superphosphate and Thomas 

 phosphate as sources of phosphoric acid, U. J. Mansholt 

 {Orgaan Ver. Oudlcer. Bijl's. LandhomcscJiOoI, I'B (1900), No. lIt3.,2W' 

 108^ 109). — Notwithstanding the claims of investigators that ground 

 bone is inferior to other sources of phosphoric acid for fertilizers, 

 the former remains popular with farmers, especially in England. The 

 author thought it desirable that field experiments extending over more 

 than one year should be undertaken in order to determine the efi'ect of 

 the bone meal during the second j-ear. For such an experiment a piece 

 of sandy loam was selected and divided into 10 parts, each 50 square 

 meters in size. The entire field was fertilized with 250 kg. of sulphate 

 of ammonia (20 per cent nitrogen) per hectare and 200 kg. of sulphate 

 of potash (50 per cent KgO) per hectare, in order to insure the presence 

 of an abundance of nitrogen and potash. In the spring of 1898 the 

 whole field received nitrate of soda at the rate of 300 kg. per hectare. 

 Two of the plats received no phosphate, while to the others were 

 applied superphosphate, Thomas slag, bone meal with the fat removed, 

 and bone meal with the gelatin removed. In each case enough of the 

 phosphatic fertilizer was used to make 100 kg. of phosphoric acid per 

 hectare. 



Rj^e was planted on all the plats in November, 1897, and in the spring 

 of 1898 the stand was very satisfactory. The rye was harvested in 

 August, 1898, and peas planted for the following crop. For this crop 

 no fertilizers were used. The increase in grain for the plats receiving 

 phosphates over those receiving no phosphates was for the 2 years as 

 follows: 



Increase in yield due to different 2^hosphates. 



Superphosphates 



Thomas phosphates 



Bone meal (fat removed) 



Bone meal (gelatin removed). 



In every case the results showed that on light soils the bone meal is 

 in the long run equal ai least co superphosphate and Thomas slag. — 



H. M. PIETERS. 



Introduction to field experiments -with fertilizers, A. L. Knisely 



{JSfeiu York Cornell Sta. Bui. 179., pp. '285-318, Jigs. 8). — This bulletin 

 gives the plan and object of cooperative field experiments with ferti- 

 lizers commenced under State appropriation in 1897. During the 3 



