Effect of trifluralin on growth, earliness and value of tomato fruits.
Summ ar y
Pot trials conducted in a glasshouse have madę it possible to observe that phytotoxicity of trifluralin to tomato depended on the soil: growth of tomato plants was strongly hindered in pure quartz sand by a 0,48 kg/ha dose of AS (active substance), whereas in hotbed soil rich in organic substances even a 1,92 kg/ha dose of AS did not affect negatively the growth of tomatoes. The phytotoxic effect produced on tomatoes cultivated in sand finding expression in stunted growth were already visible after two weeks of development, reaching their peak four weeks after the datę of treatment; the stunting was more pronounced in the root system than in the shoots. Four weeks after treatment and planting of the seedlings the aerial shoots of tomatoes were found to contain increased amounts of nitrate nitrogen and of potassium in comparison with the untreated, check plants.
As regards doses applied for weed-killing (0,72—1,8 kg/ha of AS) fruit setting was not found to be affected negatively by trifluralin, nor was the yielding dynamics under conditions of soils destined for tomato cultivation. Nor were there found any ill effects of this herbicide on the contents of dry matter, sugars, (b-carotene and total acidity of tomato fruits.