Dependence of weed infestation of oat crops (Avena sativa L.) on seeding rates under cryolithozone conditions

Abstract

On permafrost floodplain meadow soils of Yakutia (case study of the Khangalasskiy District) from 2022 through 2024, the experiments were conducted to study the dependence of weed infestation of common oat (Avena sativa) crops on seeding rates (4.5, 5.0 (K), 5.5 and 6.0 million seeds per ha). The research objectives were as following: 1) to study the effect of oat (Avena sativa L.) seeding rates on weed infestation of crops; 2) to determine the number of weed seeds in oat (Avena sativa L.) crops depending on different seeding rates; 3) to determine weed species in oat (Avena sativa L.) cenosis; 4) to determine forage yield and calculate the economic efficiency of oat growing. The soils of the plot are permafrost-floodplain meadow sandy loams. The agrochemical composition of the soil is represented by a low content of humus (2.0%), mobile phosphorus (189 mg kg), mobile potassium (44 mg kg), pH 8.3. The research targets were oat plants (Avena sativa L.) of the variety Rovesnik and weedy forbs. The accounting area of the experimental plots is 25 m²; the layout of the variants is systematic. Row seeding was used. The results of the experiments allowed determining that with increasing seeding rates of oats (Avena sativa) from 4.5 to 6.0 million seeds per ha, the level of weed infestation decreased from 5.2 ± 1.5% to 2.4 ± 0.6%; the number of weed seeds in the soil decreased by 1.9-3.2 seeds per 100 g of soil. With a seeding rate of 6 million seeds per ha, the highest forage yield was achieved (11.8 t ha), exceeding the control by 16.8%, with high profitability - 186.3%. The most common weeds in oat crops (Avena sativa) are couch grass (Elytrigia repens), field sow thistle (Sonchus arvensis), black-bindweed (Fallopia convolvulus), Yakut wormwood (Artemisia jacutica), and wild oat (Avena fatua).