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FIELD INVESTIGATIONS CONCERNING THE SELECTIVE PHYTOTOXICITY OF DI‐ALLATE TO AVENA SPP. IN WHEAT AND BARLEY
Author(s) -
HOLROYD J.
Publication year - 1964
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1964.tb00283.x
Subject(s) - avena , agronomy , crop , sowing , tine , hordeum vulgare , drilling , environmental science , biology , poaceae , materials science , engineering , structural engineering , metallurgy
Summary. The following factors influencing the selectivity of di‐allate against Avena spp. in spring wheat and barley have been investigated in seven field experiments: (a) depth and degree to which the herbicide is mixed with the soil, (b) time of application of the herbicide relative to sowing the crop, (c) implement used to incorporate the herbicide with the soil, (d) depth of germination of the Avena spp. Di‐allate and tri‐allate incorporated relatively deeply before drilling the crop controlled Avena spp, much more effectively than when incorporated shallowly by chain‐harrowing after drilling, but the pre‐drilling treatments were also more toxic to the crop. In wheat, di‐allate incorporated shallowly after drilling was slightly more selective than when incorporated more deeply before drilling but in barley there was no evidence to favour either time of application. Pre‐drilling treatments incorporated by a rotary cultivator were a little more selective to both crops than those incorporated by springtine harrows. Tri‐allate was more selective than di‐allate, in wheat, when incorporated before drilling the crop. There was no evidence regarding its selectivity as a post‐drilling treatment. The initial distribution of the herbicide in the soil, after incorporation by: (a) spring‐tine harrowing once, (b) rotary cultivating once or twice, or (c) chain harrowing once, was measured in one experiment by a fluorescent tracer technique. The results showed that ordinary farm implements give a very uneven distribution (both vertical and lateral) of herbicide in the soil. In the field, di‐allate and tri‐allate incorporated with the soil shallowly after drilling proved to be less selective and less active than similar treatments in the glasshouse. It is suggested that the reduced selectivity of these treatments in the field is due to loss of herbicide by vaporization and retention of the herbicide by the soil under dry conditions. The importance of the various factors influencing the selectivity of di‐allate and triallate in the field is discussed in the light of the results of these experiments and those of other research workers (particularly Parker, 1963). Essais de plein champ sur la phytotoxicité sélective du di‐allate envers les Avena spp. dans le blé et l'orge