EFFECT OF SOWING RATES AND BIOPREPARATIONS ON THE FORMATION OF NODULE BACTERIA IN THE ROOTS OF CROTALARIA

Аннотация

This article presents the effect of sowing rates and biopreparations on the number of nodule bacteria formed in the roots of the non-traditional legume crop Crotalaria juncea L., cultivated as a secondary crop under the conditions of meadow-alluvial soils in the Khorezm region. It has been scientifically substantiated that when Crotalaria is sown at different seeding rates with the application of biopreparations, the number of nodule bacteria per plant ranges from 8 to 62. However, as the seeding rate increases from 16 kg/ha to 24 kg/ha, the number of nodules decreases from 14 to 25. Furthermore, when seeds are treated with various biopreparations, the number of nodules increases by 18–47 compared to the untreated control variant. Keywords: Meadow-alluvial soils, Crotalaria juncea, nodule bacteria, “BIST”, “AZOS-UZ” biopreparations. Taking into account the possibility of obtaining 2–3 harvests per year from the irrigated lands of our republic, the correct selection and cultivation of legume crop species and varieties that contain high-quality protein and can positively address the existing problem of protein deficiency as a secondary crop is extremely important for improving soil fertility. As a result of the activity of nodule bacteria living in the roots of legumes, atmospheric nitrogen is assimilated, leading to the accumulation of biological nitrogen in the soil, an increase in the amount of organic matter, improvement of the soil’s water-physical properties, enhancement of fertility, prevention of secondary salinization, and a 20–30% increase in the yield of crops planted after legumes, as recorded in scientific sources. According to D.W. Reeves et al. [5], since Crotalaria species belong to legumes, they accumulate nodule bacteria in their roots, thereby improving soil fertility. Moreover, Crotalaria can also be used as mulch. The advantage of using legumes as organic mulch rather than as green manure lies in the fact that when the plant is left as mulch, 30.4–32.2 kg of nitrogen per 0.4 ha is formed in the soil during the winter season. 155 THEORETICAL ASPECTS IN THE FORMATION OF PEDAGOGICAL SCIENCES International scientific-online conference R.A. Garcia et al. [3, 6] recommended sowing Crotalaria immediately after harvesting maize and soybean crops. In this way, the land remains fallow for a shorter period, and the soil does not undergo degradation. It was recorded that in fields where Crotalaria was sown, the amount of nitrogen in the 0–5 cm soil layer increased. Furthermore, in crop rotation systems, when maize was planted after Crotalaria, both the grain and green mass yields as well as the quality of maize improved [2]. S. Negmatova and Z. Babaeva [1] recommended treating Crotalaria seeds with bacterial strains before sowing in order to accelerate plant growth and development and to stimulate the formation of a large number of root nodules. In addition, according to M. Nurullaeva [4], under the conditions of Khorezm region, when the number of root nodules on Crotalaria roots was studied, the highest accumulation of nodules was observed during the podding–ripening stage. When 18 kg/ha of seeds were sown during the period of April 20–25, Crotalaria produced 36 nodules per plant, with the average weight of nodules per plant amounting to 0.684 g. In the conducted scientific experiments, the number and weight of root nodules on Crotalaria roots, cultivated as a secondary crop, were studied during the flowering stage before each harvest. The experimental field was rotated annually under a crop rotation system, with trials carried out on different plots each year. In the experiment, Crotalaria seeds were sown with the application of biopreparations according to the experimental design. According to the data obtained in 2024, during the flowering stage before the first harvest, the number of root nodules ranged from 5 to 39, with the control variant (without biopreparations) showing very few nodules. Before the second harvest, the number of nodules increased further, ranging from 8 to 62. 156 THEORETICAL ASPECTS IN THE FORMATION OF PEDAGOGICAL SCIENCES International scientific-online conference Appearance of nodule bacteria formed on the roots of Crotalaria When observing the effect of sowing rates on the number of nodules on Crotalaria roots, it was found that as plant density increased, the number of nodules per plant decreased. For example, in variants where 400,000 seeds per hectare were sown, the number of nodules per plant ranged from 15 to 62; when 500,000 seeds per hectare were sown, the range was 13 to 58; and when 600,000 seeds per hectare were sown, the number decreased further to 8 to 37, i.e., by 7–25 nodules. The highest number of nodules per plant was observed in the variants with 400,000 seeds per hectare. Along with sowing rates, the effect of biopreparations on the number of nodule bacteria was also studied. Table 1. The number of nodule bacteria formed on the root of a single Crotalar