SOILS — FEETILIZEES. 25 



Fertilizer experiments with transformation products of lime nitrogen, 

 H. Kappen {handle. Vers. Stat., 86 {1915), No. 1-2, pp. 115-136, flg. i).— Plat 

 fertilizer experiments with mustard on a light sandy garden soil to determine 

 the relative values of urea obtained from lime nitrogen by a patented process, 

 urea nitrate, ammonium sulphate, guanidin nitrate, and sodium nitrate as 

 sources of nitrogen are reported. Thirty walled-in plats 1 meter deep and hav- 

 ing 1 square meter (10.76 sq. ft.) of surface were used. The soil befoi*e treat- 

 ment had a total nitrogen content of 0.051 per cent. The plats were completely 

 fertilized, I'eceiving 2.5 and 5 gm. of nitrogen in the different forms mentioned. 



The increase in dry matter and nitrogen in the crops of the fertilized plats 

 over those of the control plats indicated that sodium nitrate in single and 

 double applications produced the best results, followed in order by urea, am- 

 monium sulphate, urea nitrate, and guanidin niti'ate. There was, however, 

 little difference between the results obtained by single and double applications 

 of sodium nitrate and by double applications of sodium nitrate and of urea. 

 Considering the effectiveness of the nitrogen of the sodium nitrate to be 100, 

 the relative values of the other fertilizers were estimated from the results 

 obtained to be 78 for urea, 53 for ammonium sulphate, and 35 for urea nitrate. 



To determine the after effect of the different fertilizers, mustard was again 

 planted on the same soil. Better results were obtained with single than with 

 double applications of urea in these tests, and the guanidin nitrate, which pro- 

 duced an almost negligible increase in crop yield in the first experiments, had 

 a mai'ked after effect. Ammonium sulphate and urea nitrate had a less marked 

 after effect and sodium nitrate in both single and double applications had very 

 little after effect. 



Considering the total increase in crop yield in both experiments, the urea 

 stood first in value, followed closely by sodium nitrate, while the other fertilizers 

 showed the same relative values. Laboratory tests of the urea nitrate and 

 guanidin nitrate xised in the plat experiments led to the conclusion that the 

 relative inactivity of these fertilizers is due to their content of dicyandiamidin 

 nitrogen, only a small part of which is available to plants. 



Ammonification experiments in a garden soil with urea, dicyandiamidin 

 nitrate, and guanidin nitrate showed that the urea v/as rapidly ammonified, 

 while ammonification was very slow and limited in the soil treated with the 

 other two fertilizers. The guanidin nitrate is, however, considered to be of 

 some value as a nitrogenous fertilizer, owing to its nitrate content. 



[Experiments with superphosphates], A. J. Pekkins and W. J. Spafford 

 {Jour. Dept. Agr. So. Aust., 18 {1915), No. 6, pp. ^84-^56).— Detailed results of 

 experiments with superphosphates on wheat and grass lands in South Australia 

 from 1905 to 1913, inclusive, are reported. 



These results have shown that water-soluble phosphatic fertilizers are very 

 effective on the greater part of the South Australian wheat and grass lands. 

 An application of 2 cwt. of superphosphate increased the wheat crop on the 

 average 36 per cent, the hay crop 37 per cent. The effect was much more 

 pronounced in dry seasons than in wet seasons and was least pronounced in late 

 seasons. Wheat receiving superphosphate blossomed and matured earlier than 

 unfertilized wheat. An application of 2 cwt. of superphosphate gave higher 

 yields than either 1 cwt. or 3 cwt. Applications of from ^ to 3 cwt. on the wheat 

 crop very materially improved the grazing capacity of the land when left out 

 of cultivation, the improvement being in proportion to the amount of super- 

 phosphate applied. The combined cropping and grazing cash returns exceeded 

 the cost of the fertilizer used and there was a net balance of profit when the 

 application of superphosphate did not exceed 2 cwt. An application of 3 cwt. of 



