Features of control of rooster millet – Echinochloa crus-galli (L.) Pal. Beauv. in crops of sown rice – Oryza sativa L.

Abstract

Cultivation of rice in contrast to other cereals has its own specifics. The combination of heat, water, intense lighting and a high agrobackground in rice checks contributes not only to the successful vegetation of rice crops, but also to many types of weeds. Therefore, the protection of rice crops from weeds is an important issue.

The aim of the research was to analyze the shortcomings and develop ways to increase the effectiveness of weed control systems for rice crops.

The experiments were small-scale field experiments conducted in 2018–2020 in crops (rice checks) of the Rice Institute of NAAS of Ukraine. (Antonivka village, Skadovsk district, Kherson region). The size of the sown experimental plot was 66 m², the accounting area was 50 m². The experiments were repeated 4 times. Accounting and analysis were performed in accordance with the specifics of the requirements "Methods of testing and application of pesticides" edited by Professor S.O. Tribel, Methods of research of soils and plants and Methods of carrying out researches in beet growing. Yield of rice crops was determined by continuous harvesting of accounting plots on all repetitions of variants with a special selection combine "Sampo-2000".

The potential contamination of the soil from rice checks in the horizon 0–10 cm is 12987.8 pcs/m² of live weed seeds, including rooster millet
1381.0 pcs/m².

Herbicides applied to the soil with adsorbents reduced the number of weed seedlings in rice crops. Frontier Opima, 72 k.e. at a rate of 1.2 l/ha with adsorbent reduced the number of weed seedlings by 77.1%, including millet rooster by 77.2%. Dual Gold Herbicide, 960 EC at a rate of 1.4 l/ha with absorbent reduced weed levels by 80.3%, including rooster millet by 81.8%.

The presence of adsorbents near rice plants significantly increased the level of herbicides selectivity, but even under such conditions, the manifestations of phytotoxicity of herbicides to crop plants were recorded. The highest level of phytotoxicity in the experiments was in the herbicide Frontier Optima, 72 k.e. at a rate of 1.2 l/ha. with adsorbent. Reduction in the density of standing rice plants averaged 35.1%. The lowest manifestation of phytotoxicity was in the herbicide Daul Gold, 960 EC at a rate of 1.4 l/ha with adsorbent. The decrease in standing density was 16.9%

Among the herbicides used on weed seedlings in rice crops, the highest level of effectiveness was shown: Divikston, 25 NeoEC at a rate of 12 l/ha. The total weed reduction was 93.2%, the yield of rice crops was 8.72 t/ha or 76.3%, Topshot, 113 OD m.d. at a rate of 3.0 l/ha. Overall weed reduction was 90.2%. The yield of rice crops was 6.91 t/ha or 60.5% respectively from the maximum in the experiments – 11.43 t/ha.

A promising way to increase the level of herbicides selectivity to rice plants and biochemical activity to cereal weeds, especially millet rooster, is the use of physical adsorbents. Their rational introduction into the rows of crop plants allows to increase the selectivity of soil preparations and achieve their high protective effect in combination with the action of herbicides on the seedlings, and to obtain a high yield of rice crops.