WEEDS AND WEEDING 61 



short space of time all the young plants will lift themselves up 

 again. It is also worthy of note that when the soil is thoroughly 

 pulverized during the preparation of the land by the spring 

 and fine harrows and a raft of boards with pieces of wood 

 arranged crosswise on the underside of the raft, the tendency 

 of any weeds to take root is reduced to a minimum. 



The rotation of crops greatly assists in retarding the growth 

 of weeds because the different kind of treatment required 

 for each variety of crop strikes at each kind of weed in its 

 turn. 



Liming is of considerable value in subduing the corn 

 marigold. 



Manuring generally is a valuable aid in the war against 

 weeds for it enables the crop to keep pace and even outrun 

 the growth of the weeds. Mineral manures, being free from 

 weed seed and unlike farm-yard manure, tend to reduce weeds 

 to a minimum. Nitrogenous manures favour their growth. 

 In undunged and untilled land the weeds are most prolific. 



The charlock is sometimes so rank in a field of growing flax 

 as to discourage weeding by hand. In such circumstances 

 the weeds may be effectively destroyed by spraying the field 

 of young plants when about 5 or 6 in. in height with a 2, 3 

 to 4 per cent, solution of sulphate of copper about 121bs. 

 of copper sulphate to 40 gallons of water per acre being a 

 good average. The solution should not be stronger than 

 4 per cent, as it would then be liable to permanently damage 

 the crop in which the weeds were growing. It should be 

 distributed by a machine which generates a fine spray under 

 compressed air. The copper sulphate should be 98 per cent, 

 purity and the water soft ; wooden tubs or barrels should 

 be used for the mixture. 



63. Flax Pests and Diseases. Weeds harbour both animal 

 and plant pests which spread into and harm the crops. The 

 flax plant pest is a species of fungus micro-organism 

 commonly called rust. Recently the farmers in Ireland 

 experienced a considerable loss with their early sown flax 



