53 



XXXVII. Winifred E. Brenchley. ''Eradication of 

 IVecds by Sprays and Manures." Journal of 

 Board of Agriculture, 1919. Vol. XXV. pp. 

 1474-1482. 



The chemical substances used as weed killers may be divided 

 into two groups : — 



1. — Chemicals that merely destroy the weeds and have no 

 direct beneficial action upon the g-rowth of the crops. These sub- 

 stances are usually applied in the liquid form as sprays. 



2. — Compounds that not only destroy the weeds but also 

 exercise a manurial action, thus directly benefiting the crop at a 

 later date. These substances are usually very finely ground 

 manures and are applied as dry powders when the leaves are damp. 



1. — Sprays. Most of these are corrosive in nature and des- 

 troy the delicate plant tissues, either killing the weeds outright or 

 so crippling them that they cease to be active competitors with the 

 crop. The chemicals are applied in solution, the strength varying 

 according to circumstances. The most commonly used sprays are 

 copper sulphate, iron sulphate, and sulphuric acid, but other sub- 

 stances are occasionally employed, including nickel sulphate, 

 arsenite of sodn, potassium chloride and sodium hydrogen 

 sulphate. 



Copper sulphate is effective in eradicating charlock, and is also 

 useful against spurry and poppies. Iron sulphate destroys char- 

 lock, but is better than copper sulphate for eradicating poppies and 

 corn buttercup. Sulphuric acid is one of the few sprays that has 

 been found to clear grass land of bracken. 



2. — Manures. During the last few years attempts have been 

 made to destroy weeds on arable land by the application of finely 

 ground manures, especially cyanamide and kainit, and on grass 

 land by the use of lime, gas-lime and salt, and a fair measure of 

 success is considered to have rewarded the effort. Calcium 

 cyanamide and kainit have been used in eradicating charlock and 

 other weeds, but the results are somewhat variable. Salt is occa- 

 sionally useful in reducing weeds, especially on grass land, and 

 lime also acts beneficially by making the soil less suitable for some 

 of the worst pests on sour land, as spurry, sheep's sorrel, corn 

 marig-old and annual knawel. 



Taking all things into consideration, the use of finely ground 

 manures as weed killers offers possibilities, but up to the present 

 the results have been so uncertain and variable that it is not yet 

 advisable to make definite recommendations for their use. 



XXXVIII. E. J. Russell. '' Report on the proposed 

 Electrolytic Treatment of Seeds (Wolfryn pro- 

 cess) before Sowing.'' Journal of the Ministrv 

 of Agriculture, 1920. Vol. XXVI. pp. 971-981. 



A discussion of the results of pot experiments made to ascer- 

 tain whether the proposed electrolytic treatment of seed was effec- 

 tive in increasing crop production. In certain cases, increases in 

 yield seemed to be obtained, but in the main the treatment cannot 

 be relied upon to give a successful result : twice, or possibly three 

 times, out of seven it apparently succeeded ; once it apparently did 

 harm, and in the remaining cases it did no good. 



