'2:]S THOMAS -SLAG OR BASIC CINDER. 



These experimenters aijplied the slag t<j the turnip wop, and 

 compared its effect with those of superphosphate, precipitated 

 l)hosi)hate, ground Cambridge coprolites, dissolved slag, and also 

 mixtures of slag and superphosphate. 



The results they obtained show that tJie slag possesses a very 

 notable manurial value. When equal weights (viz., 4 cwt. per 

 acre) of the manures were applied, it was found that on the 

 chalky soil of Downton superphosphate gave an increase of 140 

 cwt. per acre over the adjacent unmanured plots, the slag gave 

 an increase of 90 cwt, per acre, and the coprolites an increase of 

 21 cwt. per acre. On the clay soil of Ferry hill the increase was 

 respectively 170, 220, and 151 cwt. The slag was therefore far 

 behind the superphos])hate on the chalk soil, but rather in front 

 of it on the clay, while in both instances it was superior to the 

 ground coprolites. When ecjual wadghts of phosphoric acid were 

 employed, the superphosphate was superior to the slag. 



The authors explain that the slag contained only 14 ])er cent, 

 (jt phosphoric acid, and that it was not as well ground as the 

 coprolites, but they do not say what was its state of fineness. 

 Had the fineness of grinding been carefully noted or controlled, 

 it Avould have added much to the value of these experiments. 



A number of experiments have been made with Thomas-slag 

 in Germany on the farms attached to the agricultural schools 

 and colleges, and the results are published in Biedermann's 

 Centralblatt der Arjrlcultiir-chewie and the Jd/ircsbericht der 

 Af/ricuUur-ckemic for 1886. The effects produced by the 

 slag are far from uniform. Professors Fleischer, Fitbogen, 

 Maercker, and Stutzer describe their experiments made in 

 \arious ways with various crops, and it would seem that the 

 best results are obtained on moss and moorland, where there is 

 great store of organic matter, also that the manure does very 

 Avell on clay land, and on wet land generally. It is probable that 

 the better results obtained on these soils is due chiefiy to the 

 caustic lime contained in the manure, for it is on such soils that 

 lime is applied with greatest advantage. 



The slag has been found very suitable for cereals and lor 

 grass, but not for potatoes. It was found, however, that the 

 effect of the slag used for the potatoes was distinctly visible on 

 the succeeding oat or barley crop. As a preparation for grass 

 or pasture it is strongly recommended, and, when used as a top- 

 dressing on wet meadows, it is found an effective manure. 



These experimenters made comparative experiments to test 

 the value of slag relatively to superphos]ihate and other forms 

 of phosphatic manure. The general result is that the slag, 

 when applied in equal (piantities with su])erphosphate, is just 

 lialf as good a manure, so that, if used instead of superphos- 

 ])hate, double the quantity must be em]>!oye(l. 



