1921.] 



Dry Si'Havinc of Charlock. 



136 



60 to 240 lb. per acre, and its destructive effect on the Charlock 

 was said to be generally satisfactory. In Ref. 7. however, a 

 comparatively recent German book which summarises a large 

 number of experiments on weed destruction, the author is much 

 less sanguine as to the value of calcium cyanamide in this 

 direction. In Ref. 6, calcium cyanamide is not recommended. 



II. Sulphate of Iron (Ferrous sulphate).* — Ref. 8 refers 

 to work of French origin; the quantity of sulphate of iron 

 used varied from 3 to 4 cwt. per acre, and was stated to give 

 satisfactory results, if applied before the flowering stage of the 

 Charlock. In Ref. 7 given above, the common crystalline 

 form of sulphate of iron is not strongly recommended, but a 

 speciallv prepared anhydrous form of the salt is said to be 

 efficacious. The latter substance, however, would be difficult to 

 obtain, and would certainly be much dearer than the ordinary 

 crystalline salt. 



III. Nitrate of Lime.t — The only reference is to an 

 experiment of German origin, and the results are not very 

 satisfactory. 



IV. Kainit.+ — The reference is to an experiment of German 

 origin. The quantity recommended is not less than 1050 to 

 1*250 lb. per acre. 



The results appeared to be very satisfactory when moist con- 

 ditions prevailed at the time of application. Ref. 7, however, 

 states that success is only possible with a powdered kainit, 

 which is a speciality of the German Potash Syndicate. 



Note. — No records have been found of any trials made with 

 powdered sulphate of copper. 



PRESENT EXPERIMENTS. 



Dry Spray Trials, 1919.— These were carried out on 

 Mr. Wilson's farm at Garforth, near Reeds. The substances 

 selected for the test were Nitrolim, 'Sulphate of Iron,' and 

 Sulphate of Copper (Bluestone). Each was obtained in as fine a 

 powder as was possible, and, in the case of the first two sub- 

 stances, the state of fineness was very satisfactory. The copper 

 sulphate was, however, a little coarse, having been partly sifted 

 out and partly ground from the stock supply kept in the labora- 

 tory. Unfortunately fresh nitrolim could not be obtained at the 



*(8) Jour. Board of Agrir., Dec, 1909, p. 761. 



(9) Jour. Board of Agric, June, 1911. p. 244. 

 t(10) Jour. Board of Agric. > April, 1911. 

 X{\\) Jour. Board of Agric., Aug., 191 I. p. 151. 



