COUCH GRASS

Timaru Herald, Volume CXL, Issue 20261, 9 November 1935, Page 15

COUCH GRASS

KILLING WITH SODIUM CHLORATE

The possibility of destroying couch without tillage is envisaged by an interesting experiment on the use of sodium chlorate for this purpose reported from the Edinburgh and East of Scotland College of Agriculture. In 1933 sodium chlorate was applied in the autumn as a spray to a couch-infested stubble; a wet spray in two applications, supplying a total of licwt of chlorate to the acre, was used in preference to an application in the dry state in order to get even distribution. The couch was almost completely killed to the depth of the furrow. Turnips -were drilled late in May, 1934, and no harmful effects of sodium chlorate on germination were noted. At this stage, the treated ground was clearer than the adjoining plot, from which three “crops” of weeds had been removed in (autumn at a cost of 32/- per acre. <i The authors recommend that a period of five months should elapse between the final application of the chlorate and the sowing of seed. It is probable that the toxicity period depends on the rainfall after application. American investigators found no loss of toxicity of sodium chlorate which had been in contact with the soil for two years.