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Sharipov Odiljon Bafoevich, Senior lecturer, Faculty of Natural Sciences Bukhara State University, E-mail: [email protected] Gafurova Lazizakhon Akramovna, doctor, of Biological Sciences, professor, Biology and Soil Faculty National University of Uzbekistan, E-mail: [email protected]
BIOLOGICAL ACTIVITY OF IRRIGATED GRASSLAND ALLUVIAL SOILS OF THE BUKHARA OASIS
Abstract: In the course of research, soil sections were cut taking into account the degree of salinity, the duration of irrigation, the mechanical composition; the profile structure, the morphological indices, the agrochemical, chemical and microbiological properties of saline soils of the Bukhara Oasis were studied. Experiments on agro-biotechnological methods of increasing fertility in the "Bafo Mardon Sharif" farm in the Bukhara region of the Bukhara district were conducted.
Keywords: soil, salinity, soil fertility, microbiological activity, bacterial preparations, molecular biological analysis, ammonifying microorganisms, fungi, actinomycetes, spores, nitrogen fixators, cotton growing, germination energy, crop yields.
Introduction: In recent years in many countries, including Uzbekistan, numerous studies have been carried out to investigate the soil biology and to introduce the agro-biotechnology in agriculture, to increase soil fertility; ideas on the role of biological activity in the soil-forming process are developing, in the growth and development of agricultural crops, in mobility of nutrient macro- and microelements, in increasing plant resistance (to salinity, drought, pollution, climate changes, etc.) [3, 5].
Thus, the increase in the yield and quality of agricultural cultures, particularly in arid areas and on saline soils, can be achieved through the high-culture farming by scientifically sound ecologically safe use of new types ofbio-fertilizer and biologics, sowing new forms of leguminous plants (especially leguminous vegetable), biomelioration with halophytes that have a positive effect on the microbiological and enzymatic activity, soil respiration and the processes of humus-forming in soil, nutrient, water, thermal soil regimes, soil-forming processes, soil evolution, and, finally, soil fertility and productive capacity [2, 6]. It follows from the above that the tasks posed in the paper are urgent: to study the properties of peculiar arid soils, to determine and introduce new
agro-biotechnologies to increase soil fertility in conditions of the Bukhara oasis (for example, in soils of the Bukhara region).
Objects and methods of research: The object under study is an irrigated grassland soils of the Bukhara oasis. The tasks are solved on the basis of the principles of comparative-geographical, stationary, laboratory methods for studying the topsoil. Materials of long-term researches carried out by scientists and the authors in 1970-2015 have been generalized. The methods of mathematical statistics (according to Dospekhov's) were use in generalizing and analyzing the data obtained. In the course of studies, 12 supporting sections have been cut in different regions, taking into account the soil conditions, the degree of salinity, the duration of irrigation and tillage, the type of agricultural use. Vast studies of the morphogenetic and physical properties of soil were carried out at stationary sites in field conditions [8].
Humus, gross nitrogen, phosphorus, potassium, mobile phosphorus and potassium, C02 carbonates, SO4 gypsum, salt composition, and mechanical composition in soil samples were determined with the standard methods of the Analytical Center of the Institute of Soil Science
and Agrochemistry of the State Committee for Geodesy (Methods of agrochemical analysis of soil and plants of Central Asia. Tashkent, 1977), Guidelines for conducting chemical and agrophysical analysis ofsoils in land monitoring. Tashkent, 2004; 1975. Guidelines for chemical analysis of soils (Arinushkina, 1970), Methods for studying physical properties of soils (Vadyunina, Korchagina, 1986) [9].
Characteristics of soils of the experimental site of the "Bafo Mardon Sharif" farm: The "Bafo Mardon Sharif" farm is located in the "Rabotikalmok (Madani-yat)" massive of the Bukhara region of the Bukhara
district. In this region, soil presents mainly an irrigated grassland alluvial soil of the II terrace of the Zarafshan river (23 differences), irrigated grassland soil of I terrace of the Zarafshan river (6 differences), irrigated gray-brown-grassland soil. In this region the soils of different degree of salinity are found: slightly-, medium- and highly saline differences.
The level of groundwater in irrigated grassland alluvial soils is about 2-2.5 m.
Mechanical composition of irrigated grassland soils
Figure 1. Physical clay
Mechanical composition of the arable horizon includes medium loamy soils, in the middle part of the profile - heavy and medium loamy soils, downward to the lower layers - medium- and light-loamy soils, in some places medium-loamy soils.
The humus content is from 0.78 to 1.05%, the degree of salinity is from slightly to moderate salinity(dense residue-
0.202- 0.704%, CI-0.038 - 0,067%. S042-0.134- 0.306%).
Mobile P205 is from 15,8 to17,0, K20 from 100 to 190 mg/kg.
The content of humus and nutrients in irrigated grassland soils of the Bukhara Oasis
Figure 2. Humus
The content of nutrients in irrigated grassland soils of the Bukhara Oasis.
250
200
150
100
50
m
P205
K20
0-20
Section 1
20-40
40-60
0-25
25-50
Section 2
0-30
Section 3
30-55
Figure 3. Phosphate and Potassion
Experimental part: In field experiments, a quarterly selection of soils was carried out during the experiments in order to study their biological activity.
Field experiments were conducted on irrigated grassland alluvial soils. Cotton variety was Bukhara 6. The bio-fertilizer "Mikroustirghich" and the biopreparation "Trichodermin" were tested in production conditions of farming. These biopreparations and biofertilizers are used in presowing seed treatment, root and foliar feeding of cotton plants, wheat and repeated crops. At the end of experiments, manual harvesting was carried out and the yield of raw cotton was recorded to determine the technological qualities of the fiber. The yield of cotton was determined by manual harvesting, and the results have shown that the main crop was obtained at the first harvest - about 70%.
Discussion of results. In the course of studies, the main population changes were studied under the influence of salinity in the main groups of microorganisms, and along the soil profile.
Analysis of publications has shown that under extreme conditions of salinization the halo-tolerant bacteria Bacillus and Micrococcus grow better then the halo-philic bacteria Halobacterium and Alococcus, even at 10-15% of the dense residue in the medium [5, 6, 7].
We have studied the microflora of irrigated grassland alluvial soils in the Bukhara Oasis. A survey of the bio-
logical activity of six sections of soils was carried out, samples were taken from a depth of 0-5, 5-15, 15-30, 30-50, 50-70 cm.
Studies have shown that not all groups of microorganisms are present in these samples. Thus, the MPA revealed the greatest variety of morphological and physiological groups (bacillus with and without spores, acti-nomycetes and cocci, like staphylococcus). Nitrogen-fixing microorganisms in the Ashby medium are revealed, mainly, in a 10-2 dilution. Exceptions were the samples, where nitrogen-fixing bacteria in a larger number were detected in almost all horizons.
The horizon of 5-15cm is represented by flat, scattered colonies of gray color with even and uneven edges. In the deeper samples, mainly mucous semitransparent colonies are identified. Despite the small morphological diversity of microorganisms, the cell titer of MPA in each horizon is high. In the 0-5cm horizon, the cell titer / ml is on average 1.106, in the horizons 5-15cm it is 1.105, in the horizons 15-30 cm, 30-50 cm, and 50-70 cm the cell titer is from 105 to 2.5.105.
Thus, soil samples of the Bukhara region in the MPA are very different both in the morphology of the colonies and in their number. Morphological diversity of cultures in samples is narrowed with depth.
The number of studied groups of microorganisms decreases in a series of weakly saline, medium - and
highly saline soils. As salinization increases, such forms of microorganisms develop that can easier tolerate unfavorable environmental conditions, (actinomycetes and spore bacteria), this indicates the energetic mineralization processes that result in low humus content.
Conclusion. Results of field research have shown the effectiveness ofagro-biotechnology in the cultivation ofcot-ton variety Bukhara 6 on irrigated grassland soils, as the year
Note that the Baikal M 1 was adopted as the standard for comparison of biopreparation Trichodermine and Microustirghich and control without treatment. The presowing soaking of cotton seeds with the Microustir-
2015 was somewhat unfavorable, dry, with high summer temperatures, dry winds, etc. In addition, soil was slightly saline, compacted with low humus and nutrient reserves.
Results has shown that in the control variant the yield of cotton was 36.6 c/ha, and in the second variant -39.7 c/ha, in the third - 30.3 c/ha, in the fourth variant -40.1 c/ha. Thus, when using biopreparations, the yield of cotton is 3-4 c/ha higher than the control variant.
ghich preparation of 100 ml/t followed by spraying the vegetating plants promotes an increase in the germination capacity of seeds and the germination energy is greater than that of the control and reference variants.
Table 1.- The yield of cotton variety Bukhara 6 on irrigated grassland alluvial soils, c/ha
Variants Repetitions average Including harvesting Harvest fracture
I II III I II I II
Control 36.2 37.7 36.6 36.6 25.2 11.4 68.9 31.1
Baikal M 1 40.4 38.6 40.2 39.7 27.1 12.6 68.3 31.7
Microustirghich 40.3 40.0 46.5 40.3 27.2 13.1 67.9 32.1
Trikhodermin 40.2 40.2 40.1 40.1 27.3 12.8 68.2 31.8
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3. Gafurova L. A., Saidova M. E. Soils near the Aral Sea and their Biological Activity. Tashkent: Fan,- 2015.- P. 108-109.
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6. Dzhumaniyazova G. I. Phosphoro-mobilizing Bacteria and Biofertilizers on their Basis, Thesis of Doctor of Biological Sciences. - Tashkent. - 2012.
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