Effectiveness of contact sprays in the control of annual weeds in cereal crops
1939
Singh, B.N. | Das, K.
Replicated experiments on the control of annual weeds in a wheat field of known history by the use of three contact sprays, namely, sulfuric acid, ammonium thiocyanate, and copper sulfate, indicate that the degree of control differed with the different weeds and herbicides, Anagallis arvensis and Euphorbia dracunculoides showed higher degrees of reduction than Chenopodium album, explainable on the morphological peculiarities and the relative hardiness of the weeds as well as on the quantity of spray solution adhering on the surface, while the herbicides showed effectiveness in the decreasing order of sulfuric acid, ammonium thiocyanate, and copper sulfate. Contributory factors that apparently aided in the effectiveness of the treatments are the concentration of the herbicides, the time of their application, the stage and development of the plants, the leaf area exposed, and the temperature and humidity of the atmosphere. On a statistical examination of the data, however, significant differences were not observed. The yield of the grain tended to increase with a reduction in weed density, but the differences with the control plats were not always statistically significanty. Spraying with a higher concentration of ammonium thiocyanate solution gave significantly better result because of the addition of extra nutrients besides the elimination of weed competition. Sulfuric acid spraying did not make the soil sour. The small differences in pH, if any, were not significant.
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