Scientific novelty of the obtained results. For the first time a comprehensive study of the peculiarities of weeding of rice crops, clarified the competitiveness of crops in different periods of their growing season, identified the causes of insufficient efficiency of existing herbicide application systems and developed a weed control system with herbicides with adsorbents that enhance their selectivity to rice plants.
The control system of rice weed control processes has been improved, taking into account the specific species composition of weeds, which like the culture belong to the botanical family Poaceae, and consistent application of herbicides on the stairs, which limits the ability of weeds to form mass and allows high rice yields.
Scientific provisions on the possibility of regulating the level of selectivity of herbicides to crop plants and their biochemical activity to seedlings and seedlings of weeds in crops of sown rice have been further developed.
The main results of research. The potential contamination of the upper horizon – 0–10 cm of arable soil layer in rice checks with weed seeds that could germinate, averaged 12987 pcs / m2, of which rooster millet (Echinochloa crus galli L.) – 1381 pcs / m2
Among the species composition of plants in the crops of rice sown dominated by plants: plague (Scirpus mucronatus L.) – 390 pieces / m2 or 53.8 %, millet (Echinochloa crus galli L.) – 236 pieces / m2 or 35.6 %, heterogeneous sieve (Cyperus difformis L.) – 40 pieces / m2 or 5.5 %, compact tuber (Bolboschoenus compactus Drob.) – 11 pieces / m2 or 1.5 %. The number of weed seedlings in rice crops was significant and ranged from 228.0 units / m2 to 724 units / m2.
In crops of sown rice for 100 days of joint vegetation (from emergence) weeds formed an average of 2980 g / m2 of raw or 924 g / m2 of dry mass, which reduced the yield of grains by 70.4 – 73.7 %. Plant uptake of mineral nutrition compounds by weeds reached: N – 90.5 kg / ha, P2O5 – 56.4 kg / ha, K2O – 109.8 kg / ha. This volume is sufficient for the formation of rice yield from 4.35 to 5.11 t / ha.
Soil herbicides, even in the presence of a physical adsorbent in rice crops, did not completely rule out phytotoxicity to crop plants. The highest level of phytotoxicity was recorded in the herbicide Frontier (consumption rates of 0.9 and 1.2 l / ha). Reduction of crop density in crops by 29.7 and 35.1 %. The lowest phytotoxicity was provided by the herbicide Dual Gold, 960 EC (loss rates of 1.0 and 1.4 l / ha). Reduction of standing density of rice plants by 14.9 and 16.9 %. Herbicide Command, 48KE (without adsorbent) at a rate of 0.5 l / ha reduced the stocking density of crops by 23.8 %.
The drug Divikston, 25Neu at a rate of 1.2 l / ha provided a reduction of seedlings of unwanted vegetation in rice crops by 92.3 %, the herbicide Citadel, 25OD at a rate of 1.6 l / ha by 88.2 %, the drug Topshot, 113OD m.d. at the rate of consumption of 3.0 l / ha reduced weediness of crops by 90.3 %.
The yield of rice crops was inversely related to the weed mass in the crops. The highest mass of weeds was on average 3631 g / m2 (weed control crops). The yield of such crops was low - 3.61 t / ha or 31.6 % of what was possible in the experiments.
In the protection of crops, the most effective was the system of sequential application of Dual Gold, 960 EC at a rate of 1.4 l / ha with adsorbent in the soil + Tropshot, 113ODm.d. at a rate of 3.0 l / ha on the stairs, which reduced the formation of weeds to 244 g / m2. and obtaining a grain yield of 13.81 t / ha or 92.0 % of the maximum possible in the experiments.
The yield of rice sown using an environmentally safe weed control system in the experiment was highest in the areas of option 6, an average of 10.63 t / ha of grains at a humidity of 16.08 %. Crops of option 2 (use of the herbicide Sirius z. P.) Provided 9.39 t / ha or 88.3 % of the maximum. Control of weeds in rice crops using a system of special environmentally friendly membranes is promising and after patenting and appropriate technical support for their mechanized use, can get a wide practice of implementation in agricultural production.
The economic efficiency of using the new system of protection of rice crops from weeds with herbicides (option 3) was 6284.9 UAH / ha or 28.3 % higher than the cost of the traditional system (option 2). At the same time, additional costs are offset by the amount of stored yield – 1.73 t / ha or 15.9 % higher than the level of yield using the traditional protection system. The cost of the harvest was 2569.15 UAH / t, the level of profitability – 211.38 %, which were the best in the experiments. Profit per ton of marketable products – UAH 5430.85/t, which exceeded the indicators of products from crops of the traditional version of protection (option 2) by 5.3 %.
