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Section 1. Biology
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Berdiev Tolib Tursunniyazovich, Research Institute for Soil Science and Agro chemistry, researcher
E-mail: [email protected]
Agro technologies increasing the productivity of irrigated soils in the desert zone of Uzbekistan
Abstract: The results of research aimed to improving soil fertility and crop yields in the system "cotton-winter wheat" in accordance with the agricultural technologies developed by our institute, related to soils of the desert zone are given. The ways of increasing the amount of humus, nutrients in the soil and productivity of cotton and winter wheat are demonstrated.
Keywords: soil fertility; fertilizer; enrichment of the soil; organic substances; crop yields; the carbon content of humus.
In recent years in the country's major irrigated areas there is a tendency of reducing the content of humus, the nutrients available to plants, occurrence of negative phenomena as degradation, dehumidification, erosion, salinization, compaction, etc., which ultimately leads to poor land quality and reduction of soil fertility. A prevention of these negative phenomena is possible by land reclamation and the introduction of agricultural technologies to improve all the basic properties of the soil, enriching it with organic matter and the elements of plant nutrition.
On the basis of studies at period of 2003-2010, we developed agricultural technologies applicable to soils of serozem zone, aimed to enriching the soil with organic matter, increasing soil fertility and yield of crops.
This agrotechnology includes a cultivation of major crops in system "cotton-winter wheat" and their consequent alternation with repeated crops — corn combined with bean (mung bean, soybean) and intermediate crops (oats, canola) with obligatory introduction of high amounts oforganic fertilizers-manure from different origin, organo-mineral fertilizers, composts from local raw materials on the basis of manure. This reduces the rate of applied mineral fertilizers 1.5-2 times.
The same agrotechnology, with some modifications, developed in relation to takyr-meadow and serozem-meadow soils of the desert zone in several farms of Surkhandarya and Kashkadarya regions of the republic in 2008-2011.
The paper presents the results of research on the effect of applied agricultural technology on selected fertility indicators of irrigated takyr-meadow soils and productivity of crops (cotton, winter wheat), conducted in 2009-2011 on the territory of the farm of Angor district of Surkhandarya region.
Research methodology
Field experiments with the cultivation of major, repetitive and intermediate crops conducted by Soyuz NIHI (All-union research institute of cotton science) methodology. Soil analyzes were performed according to standard methods described in the manuals of Soyuz NIHI (1977) and E. V. Arinushkina (1970).
Experiments with cotton, winter wheat and other crops were placed in 5 cases, repeated 3 times. The size of the plot — 72 m2, the total area — 1080 m2.
Results
The results of the soil analysis on change the content of total humus in three years of experiments in cotton cultivation (SpringFall 2009), winter wheat (fall 2009 -summer 2010), sowing repeated crops (Summer-Fall 2010), intermediate (Fall 2010-Spring 2011) and re-cotton (spring-fall 2011) showed a significant increase of its content in the variants, which used the proposed agro technology with the introduction of various norms of manure with reduced 1.5-2 times the norm of mineral fertilizers, as well as microbiological preparation (MERS).
Thus, in the control variant without fertilizers from spring 2009 to the autumn 2011 there is decrease in the carbon content of humus in the upper arable (0-30 cm.) and subsurface (30-50 cm.) soil horizons at 0.095 %, which is equal to 7.64 t/ha. In variant with introduction only complete the norms of mineral fertilizers during this period was an increase in these layers of soil carbon content of organic substances in the 0.097 % and 0.050 %, respectively. This is for the 0-50 cm. soil layer is 5.88 t/ha. Such an increase in the carbon content oforganic matter was due to the better development of the plants due mineral fertilizers and more decayed root and crop debris.
The variants of the experiment, which used the proposed agricultural technology with application of organic fertilizer (manure) at the rate of 20 and 40 t/ha annually for three years and at a low of 1.5 and 2 times the rate of mineral fertilizers, in the 0-50 cm. soil layer was an increase amounts of organic substance on the 0.177 % and 0.239 %, which is equal to 7.08 and 9.56 t/ha, respectively (Fig. 1). These values are higher than the control group with mineral fertilizers by 1.2 and 3.68 t/ha. In variant of the experiment which used a microbiological preparation at rate 100 ml/ha with 1.5 times the low rate of fertilizers, increasing the amount of organic matter in the 0-50 cm. layer was 0.132 % or 5.28 t/ha, which is close to control variant which used the full rate of fertilizer.
Agro technologies increasing the productivity of irrigated soils in the desert zone of Uzbekistan
Fig. 1. Dynamic of changes in the humus content of the soil in cultivation system "cotton-winter wheat", repeated and intermediate crops, 2009-2011 (% of the soil weight)
Similar positive results were obtained in variants where the applied agro-technologies with respect to the dynamics of content of phosphorus and potassium available to plants in 0-30 and 30-50 cm. soil layers.
The obtained data present, for the 3 years of application of agricultural technology, including a succession of major crops with repeated and intermediate crops and annual application of high amounts of organic fertilizers, the possibility of reducing the norms of mineral fertilizers in 1.5-2 times. Thus, in experimental variants with organic fertilizer, a significant increase in organic matter content of the first half-meter layer of soil and the amount of phosphorus and potassium in forms available to plants are observed at the level of the control variant where full norms of fertilizers applied. Thus, in these variants, the 0-30 cm. layer of soil contains 26-35 mg/kg transfer phosphorus, and 200-300 mg/kg exchangeable potassium, which belongs to the average level of supply.
These positive aspects of applied agricultural technology on soil fertility indicators are affected in relation to the productivity of cultivated major crops — cotton and winter wheat.
Derived data show that in variants 3-4 which applied agricultural technology and introduced different norms of organic
fertilizers together with reduced 1.5-2 times of mineral fertilizer, cotton yield was 3.60 and 3.79 t/ha. At the same time gain from the control variant 2, which used the full rate of mineral fertilizers amounted to 0.43 and 0.56 t/ha. In variant 5, which the microbial preparation is used with a low rate of 1.5 times of mineral fertilizer yield over the control variant was slightly reduced — 0.07 t/ha.
Positive effects of organic fertilizers on cotton productivity also marked in the first 2009 year of the study. However, this year, with cotton yield in the variant-2 with a full rate of mineral fertilizers 3.18 t/ha, in variants with organic fertilizers at rates of 20 and 40 t/ha, increase was 0.38 and 0.52 t/ha respectively. In variant — 5 with microbiological preparations yield decreased by 0.16 t/ha.
Conclusions
These results point out that the proposed agro-technology, including the succession of major crops with repeated and the intermediate crops with the introduction of mandatory annual high rates of organic fertilizers at 20 and 40 t/ha, together with reduced 1.5-2 times of mineral fertilizers, both in terms of serozem zone and the desert, in the short term (2.5-3 years) can increase soil organic matter content and thus increased cotton yield by 0.4-0.5 t/ha.
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References:
Tashkuziev M. M. Influence of organic matter managing agricultural technologies to the fertility of irrigated typical serozem soils. Proceedings of the international scientific conference devoted to the 60th anniversary of the Institute of Soil Science, named after U. U. Uspanov, "Status and prospects of development of soil science". - Almaty, 2005. - P. 99-100.
Tashkuziev M. M., Ochilov S.K., Berdyev T. T., Sherbekov A. A. Agrotechnologies aimed to increasing soil fertility and yield of crops. International scientific-practical conference "Agricultural science - to agriculture." Book 2. - Barnaul, 2013. - P. 235-237. Methodology of field experiments on cotton in tems of irrigation Soyuz NIKhl, 1981.
