THE EFFECT OF ORGANOMINERAL FERTILIZERS ON THE DEVELOPMENT AND PRODUCTIVITY OF CROPS IN COTTON CROP ROTATION

ABSTRACT

This article presents the results of research on the application of new forms of organic and organomineral bacterially treated phosphorite-humic fertilizers to crops in cotton crop rotation and their effects on growth, development, and productivity indicators.

Keywords: mineral, organic, bacterially treated fertilizers, cotton, winter wheat, yield, vermicompost, irrigated meadow soil.

Introduction: It is well known that the application of organic and phosphorus-containing organomineral fertilizers promotes the formation of organic acids in the soil. This improves the soil nutrient regime and mobilizes soil phosphates, while reducing the retrogradation of applied phosphorus fertilizers, thereby enhancing their efficiency [1, 2].

Improving the nutrient regime, enhancing soil fertility, and increasing the yield of cultivated crops depend significantly on the combined use of mineral fertilizers and new types of organic and organomineral fertilizers. These fertilizers, enriched with organic matter and essential nutrients, are obtained through fermentation and microbiological activation, such as vermicompost, biogas technology by-products (BMG), and bacterially treated phosphorite-humic fertilizers.

Materials and Methods: The research was conducted on irrigated meadow soil in the Kibray district, Tashkent region, on experimental plots of the Research Institute of Cotton Breeding, Seed Production, and Agrotechnology. Field experiments with cotton were conducted according to the SoyuzNIKI methodology [3]. Soil analyses were performed using standard methods described in SoyuzNIХI manuals [4].

Experimental design:

1. N₁₅₀P₁₀₅K₇₅ – control, standard farm fertilizer rate
2. N100P70K50 – background, 25 % reduced fertilizer rate
3. Background + 2 t/ha bacterially treated phosphorite-humic fertilizers
4. Background + 1.5 t/ha BMG
5. Background + 2.5 t/ha BMG
6. Background + 2.5 t/ha vermicompost

Results: To determine the effect of new organomineral fertilizers, special field experiments with cotton were conducted under production conditions. The purpose was to mobilize soil phosphates and increase the efficiency of applied phosphorus fertilizers on irrigated meadow soil.

This article focuses on the effects of these organic fertilizers on the growth, development, and productivity of cotton.

The results obtained from this experiment have been previously published [5]. The application of mineral, organic, and other types of fertilizers is a key factor in the growth and development of all agricultural crops.

Our phenological observations showed that in the early stages of cotton development (June 16), differences in main stem height were noted: in control variants 1 and 2, the height was 36.2 and 35.2 cm, respectively, while in the variants with new organic and organomineral fertilizers, the heights were 38.3, 43.2, 49.9, and 52.8 cm (table).

During the flowering-fruit formation phase (July 15), the highest plant height was recorded in variant 6, where vermicompost at 2.5 t/ha was applied along with a reduced rate of mineral fertilizers. This can be explained by the fact that in these growth stages, cotton plants develop a strong root system and actively absorb nutrients compared to the control variants 1 and 2. The increase in main stem height continued in all experimental variants through the fruiting phase (August 18) and the ripening phase (September 20), remaining higher in all variants that received organic and organomineral fertilizers.

Various types of organic and organomineral fertilizers – BMG, vermicompost, and bacterially treated phosphorite-humic fertilizers – had a positive effect on the formation of cotton sympodial branches. The fewest branches were observed in control variants 1 and 2 during the budding stage – 3.3 and 3.5 respectively, and 5.2 and 6.1 during flowering. The largest number of bolls during flowering – 8.8 – was recorded in the variant with vermicompost. In the 2.5 t/ha BMG variant, there were 8.5 bolls; with 1.5 t/ha BMG – 7.1 bolls; and with bacterially treated phosphorite-humic fertilizers – 6.3 bolls.

Table 1.

Effect of Organic and Organomineral Fertilizers on the Growth, Development, and Yield of Cotton, 2023

At the budding–flowering stage (June 16), the highest number of green bolls was observed in the variants where vermicompost was applied – 5.4 bolls, and in the variant with 2.5 t/ha BMG – 5.0 bolls. In contrast, the control variants 1 and 2 had the lowest numbers – 2.4 and 2.5 bolls, respectively. In the variant with bacterially treated phosphorite-humic fertilizers and the 1.5 t/ha BMG variant, the number of green bolls was 2.7 in each.

Phenological observations during the fruit formation phase (July 15) showed that the number of green bolls in the control variants with mineral fertilizers (1 and 2) was 7.2 and 6.3 bolls, respectively. The application of bacterially treated phosphorite-humic fertilizers increased the number of bolls to 8.4. In the variants with 1.5 t/ha and 2.5 t/ha BMG, the number of green bolls reached 7.3 and 9.3, respectively. The highest number of bolls – 9.5 – was observed in the cotton variant fertilized with 2.5 t/ha vermicompost.

By the end of the growing season, the lowest number of bolls per plant – 9.5 – was recorded in variant 2, where a reduced rate of mineral fertilizers was applied, while in the full-rate mineral fertilizer control (variant 1), there were 12.9 bolls. The highest numbers – 19.6 and 20.0 – were found in variants with 2.5 t/ha BMG and 2.5 t/ha vermicompost, respectively. Variant 4 (1.5 t/ha BMG) was close to control 1, with 13.0 bolls, while variant 3 (bacterially treated phosphorite-humic fertilizers) had slightly more – 13.6 bolls.

In line with these growth and development indicators, data were obtained on the accumulation of dry matter in various plant organs.

Table 2.

Average Weight of Cotton Plant Organs Under Different Fertilizer Treatments (g/plant)

The highest weight of a single boll – 4.9 g – was observed in the variant with 2.5 t/ha BMG. It was followed by the variants with vermicompost and bacterially treated phosphorite-humic fertilizers – 4.8 g each. The lowest weights – 4.2 g and 4.3 g – were recorded in the control variants 1 and 2, which affected the raw cotton yield across the experiment.

The highest raw cotton yield–3.63 t/ha – was obtained in the variant with 2.5 t/ha BMG, an increase of 0.51 t/ha compared to control variant 1 (31.3 c/ha) and 9.1 c/ha over variant 2 (reduced mineral fertilizer background). In variant 4 (1.5 t/ha BMG), the yield was 3.41 t/ha–0.29 t/ha more than control 1, and 0.69 t/ha more than variant 2. In the vermicompost variant, the yield reached 3.58 t/ha, with an increase of 0.45 t/ha over control 1 and 0.86 t/ha over variant 2. Application of bacterially treated phosphorite-humic fertilizers resulted in a yield of 3.33 c/ha–0.21 t/ha more the control 1 and 0.61 t/ha more than variant 2.

The lowest cotton yield – 27.2 c/ha – was obtained in variant 2, where the reduced rate of mineral fertilizers was applied. This was 4.1 c/ha less than in control variant 1, where full mineral fertilizer rates were used.

Discussion: Special field trials were conducted to evaluate the effects of new organomineral fertilizers on cotton growth, development, and yield. During early growth (June 16), differences in main stem height were observed: control variants 1 and 2 showed 36.2 cm and 35.2 cm respectively, while fertilized variants showed 38.3 to 52.8 cm. During flowering and fruit formation (July 15), the tallest plants were observed in variant 6 (vermicompost at 2.5 t/ha), indicating more active nutrient uptake compared to control variants.

Fertilizers positively influenced the development of sympodial branches and boll formation. Control variants had the fewest bolls, while vermicompost and BMG treatments led to significantly higher numbers. At the end of the growing season, boll numbers per plant ranged from 9.5 in variant 2 to 20.0 in variant 6.

Boll weight was also highest in variant 5 (2.5 t/ha BMG), reaching 4.9 g, followed by 4.8 g in the vermicompost and bacterially treated fertilizer variants. The lowest weights were recorded in the control variants.

Yield analysis showed:

36.3 c/ha in variant 5 (2.5 t/ha BMG), an increase of 5.1 c/ha over control 1 and 9.1 c/ha over control 2     35.8 c/ha in variant 6 (vermicompost), 4.5 and 8.6 c/ha higher than control 1 and 2, respectively      34.1 c/ha in variant 4 (1.5 t/ha BMG), 2.9 and 6.9 c/ha higher            33.3 c/ha in variant 3 (bacterially treated fertilizers), 2.1 and 6.1 c/ha higher

Variant 2 showed the lowest yield (27.2 c/ha), 4.1 c/ha less than control 1.

Conclusion: The application of organic and organomineral fertilizers—such as bacterially treated phosphorite-humic fertilizers, BMG, and vermicompost—stimulates cotton growth and development and leads to higher yields. These treatments increased main stem height and boll number, resulting in a yield increase of 2.0 to 5.0 c/ha over the full mineral fertilizer control and 6.1 to 9.1 c/ha over the reduced-fertilizer background.

References:

1. Tashkuziev M.M. Chemical State of Typical Serozems and Soils in the Lower Amudarya, and Its Changes Under Fertilization, Irrigation, and Desertification. Dissertation Abstract. Tashkent, 1996, pp. 24–28.
2. Chumochenko I.N. The Role of Phosphorus in Plant Life and Soil Fertility. Moscow, 2003, pp. 28–31.
3. Methodology of Field Experiments with Cotton under Irrigated Conditions. SoyuzNIХI, 1981, p. 246.
4. Methods of Agrochemical, Agrophysical, and Microbiological Research in Irrigated Cotton-Growing Regions. SoyuzNIХI, Tashkent, 1963, pp. 270–274.
5. Tashkuziev M.M., Karimberdieva A.A., Mustafaeva S.Ch., Ochilov S.K. Effect of New Forms of Organic and Microbiologically Activated Phosphorite-Humic Fertilizers on the Dynamics of Nutrients in the Soil. II Current Issues in Soil Science, Ecology, and Agriculture. Kursk, 2018, pp. 448–453.