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POLYMER HYDROGEL – APPLICATION RATE AND WATER
SAVINGS
O.T.Malikova
PhD Student at “ISMITI”
E.N.Malikov
Assistant at “TIIAME” NRU
Q.N.Sultonov
Student at “TIIAME” NRU
https://doi.org/10.5281/zenodo.15680010
Annotation
This article presents the results of field experiments conducted on
meadow sierozem soils in the Tashkent region, where 40 kg per hectare of
polymer hydrogel was applied for the joint cultivation of cotton and soybean.
The results demonstrate that during the growing season, the efficiency of
irrigation water use increased by 15–17%, and it became possible to achieve a
cotton yield of 30.7 centners per hectare.
Introduction:
Preserving and consistently improving the productivity and
meliorative state of our valuable irrigated lands, as well as ensuring the efficient
use of irrigation water, are currently stimulating further research by our
scientists and sector specialists.
Ensuring adequate water supply for agricultural crops, saving irrigation
water, and obtaining two or more harvests from the same field within a single
season through the use of innovative technologies have become crucial.
In this regard, various scientific studies have been carried out by researchers,
including cultivating two different crops simultaneously on a single plot,
achieving high and quality yields, maintaining and enhancing soil fertility,
stabilizing the meliorative condition of irrigated lands, producing additional
food products, and using hydrogels in crop production to reduce water
consumption. These scientific efforts aim to increase the efficiency of land and
water use in cotton farming, support the economic stability of farming
enterprises, and open new opportunities for farmers during market reform
periods.
Research Methods:
To address the aforementioned issues, for the first
time we conducted field studies in the conditions of medium and heavy loamy
meadow sierozem soils at the “Mamatkarim Dilshodjon” farm located in the Orta
Chirchik district of Tashkent region. In these studies, polymer hydrogel was
applied for the joint cultivation of leguminous crops (soybean) with cotton. The
objective was to explore the influence of this method on soil fertility, seasonal
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water use, cotton productivity, and the overall efficiency of land and water
resource utilization. These efforts were directed toward providing scientific
solutions for increasing food supply, preventing ecological and meliorative
degradation of the environment, expanding agricultural production, and
improving the economic efficiency of farming.
The significance of hydrogel use in agriculture, its optimal application
rates, and hydrogel synthesis have been extensively studied, notably by
Professor A.T. Djalilov. In addition, Professors M.Kh. Khamidov, A.T.
Salokhiddinov, N.B. Egamberdiyev, and other scholars have investigated the role
of hydrogels in improving water use efficiency in cotton and companion crop
cultivation.
In the current global context, where climate change and ecological
challenges are intensifying—particularly in Central Asian countries like
Uzbekistan—water scarcity is becoming more acute. According to data from the
AgroUz website, while droughts occurred once every 6–8 years before 2000, in
recent decades, such events are now repeating every 2–3 years [2].
These negative trends naturally pose substantial challenges for the
development of agriculture. Inadequate water supply for crops leads to reduced
yields and deterioration in crop quality.
Therefore, the widespread implementation of water-saving technologies
in agricultural production and the use of modern agro-technologies that enhance
land and water resource efficiency have become critical and urgent needs of our
time.
Among such technologies, the use of polymer hydrogels in irrigated lands
stands out as an effective method.
Noteworthy are the scientific investigations of M.Kh. Khamidov, A.T.
Salokhiddinov, N.B. Egamberdiyev, and others, who studied the impact of
hydrogels on water savings when growing cotton and other associated crops.
Their findings revealed that in both hydromorphic and automorphic soils,
applying hydrogel allowed a 1,25–1,3 times reduction in irrigation water
consumption, a decrease of one irrigation event, and up to 10% increase in yield.
Hydrogel is a super-absorbent polymer capable of absorbing large amounts of
water and gradually releasing it into the surrounding soil environment when
needed. It helps retain moisture in the soil over extended periods. Experts note
that 10 grams of hydrogel can retain 2.5 to 4 liters of water, and when used
correctly, it can save 20–40% of irrigation water.
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Considering these facts and the adverse effects of current trends, we
undertook research under hydromorphic and meadow sierozem soils with
medium to heavy loam texture, aiming to preserve soil productivity, improve
meliorative conditions, and enhance the efficient use of water resources. At the
same time, our goal was to support the economic sustainability of farming
households through the application of hydrogel-based water-saving
technologies.
Results:
In our field experiments, a locally produced polymer hydrogel
was applied at a rate of 40 kg per hectare during the joint cultivation of cotton
and soybean. The study aimed to assess the effects of hydrogel and
intercropping on the agro-physical, water-physical, and agrochemical properties
of the soil, as well as on irrigation regimes, seasonal water norms, and the
number of irrigation events.
The field trials were conducted using three experimental variants: Variant
1 (Control): Conventional cotton cultivation under production conditions
without hydrogel. Variant 2 (Intercropping with Hydrogel): Cotton and soybean
were cultivated together, with polymer hydrogel applied at a depth of 15–18 cm
before sowing. Variant 3 (Cotton with Hydrogel): Similar to Variant 2, but only
cotton was grown with the application of hydrogel. In Variants 1 and 3 cotton
plant density ranged from 119 000 to 123 000 plants per hectare. In Variant 2,
the total plant density was higher—122 000 to 128 000 plants per hectare,
consisting of 51 000–53 000 soybean plants and 71 000–75 000 cotton plants.
As of September 1, boll development data were as follows: In the control variant
(Variant 1), the average number of bolls per plant was 11,8 with 5,5 open bolls.
In the cotton+soybean intercropping variant (Variant 2), the figures were 13,2
and 5,4, respectively. In Variant 3, the numbers were 12,3 and 5,3,
respectively—0,9 and 0.1 less than in the intercropped variant.
By the same date, the main stem height of the soybean plants reached 108.6 cm,
and the average number of pods per plant was 104,7.
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Figure 1. Graph of Cotton Growth and Yield According to Cultivation Methods
Calculations of cotton yield showed that in the control variant, the average
cotton yield amounted to 28,6 centners per hectare, while in the variant where
cotton and soybean were cultivated together, it was 20,9 centners per hectare.
In the third variant, where cotton was grown with the application of polymer
hydrogel, the highest cotton yield of 30,1 centners per hectare was achieved.
However, the most remarkable aspect is that although cotton yield was
significantly lower in the intercropping variant compared to the mono-cropped
cotton variant, an additional yield of 18,2 centners per hectare of soybean grain
was obtained.
Observations on irrigation practices in the experimental field showed that
840 to 1260 m³/ha of water was used for each irrigation event, and a total of
5660 to 4695 m³/ha was applied throughout the season. The number of
irrigations was five, with the first irrigation lasting 18 hours.
In the following irrigations, the duration in the control variant ranged from 18 to
20 hours, while in the hydrogel-treated variant, the irrigation duration was
reduced to 14–17 hours.
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Table 1. Number of Irrigations and Seasonal Water Norms in the Experimental
Field
Variant
Number of
Irrigations
(times)
Water Use
per
Irrigation
(m³/ha)
Total
Seasonal
Water
Use
(m³/ha)
Duration
of
First
Irrigation
(hours)
Duration of
Subsequent
Irrigations
(hours)
Cotton (Control) 5
840 – 1260 5660
18
18 – 20
Cotton
+
Soybean (with
hydrogel)
5
840 – 1260 4695
18
14 – 17
Cotton
(with
hydrogel only)
5
840 – 1260 4695
18
14 – 17
Table 2. Number of Irrigations and Seasonal Water Norms in the Experimental
Field
Variant
1st
Irrigation
(m³/ha)
2nd
Irrigation
(m³/ha)
3rd
Irrigation
(m³/ha)
4th
Irrigation
(m³/ha)
5th
Irrigation
(m³/ha)
Seasonal
Water
Use
(m³/ha)
Conventional
method
(control)
840
1180
1210
1260
1170
5660
With
hydrogel
(Variants 2
and 3)
840
930
975
1030
920
4695
This can be attributed to the fact that soil moisture content in the
hydrogel-treated variant was 8–11% higher compared to the control. It is worth
noting that, currently, water use in farming operations is organized based on a
fixed irrigation schedule. Therefore, in both variants, irrigation events were
conducted simultaneously. The only difference between the treatments was that
irrigation rates and durations were adjusted based on soil moisture content, as
presented in Table 2.
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Figure 1. Experimental field: cotton +
soybean (left) and cotton with
hydrogel treatments
Figure 2. Phenological observation
process in the experimental field
Recommendations:
It is recommended to apply 40 kg/ha of polymer
hydrogel, produced from local raw materials, under the hydromorphic, medium
and heavy loamy sierozem soils of the Tashkent region in order to improve
irrigation water use efficiency. When cotton is cultivated using this method, it is
possible to achieve a 1.5 c/ha higher yield compared to the control, while also
reducing irrigation water use by 15–17%.
Conclusions:
Based on the obtained results, it can be concluded that in
order to increase the efficiency of irrigation water use in the cultivation of cotton
and associated crops, the application of 40 kg/ha of polymer hydrogel made
from local raw materials is recommended. This approach allows for a 15–18%
reduction in seasonal water consumption. Moreover, when cotton is cultivated
with hydrogel, it is possible to obtain a 1.5 c/ha higher yield compared to the
control variant
References:
1.
Karimov, I.A. (2009). The Global Financial and Economic Crisis, and Ways
and Measures to Overcome It in the Conditions of Uzbekistan. Tashkent:
Uzbekistan Publishing House. 56 p.
2.
AgroUz website. Recommendations on the Use of Hydrogel. B.
Burkhonjonov. [in Uzbek]
3.
Djaldilov, A.T., Shirinov, Sh.D. Technology and Economic Efficiency of
Hydrogel Application. [in Uzbek]
4.
Regulation on the Introduction of Modern Water-Saving Technologies.
Resolution No. 176 of the Cabinet of Ministers of the Republic of Uzbekistan,
June 21, 2013.
5.
Sarimsakov, M.M., Akhmedjonov, D.G‘. (2016). Leguminous Crops as an
Additional Source of Income. Irrigation and Melioration Journal, No. 4(6). [in
Uzbek]
