Влияние способа полива субирригацией хлопчатника в гидроморфных условиях почв на урожай хлопка-сырца

При проведении полива хлопчатника субирригацией число поливов уменьшилось на 1–2 раза, экономия воды составила 987–1880 м³/га, междурядная обработка уменьшилась на один раз, сэкономлены горюче-смазочные материалы, прибавка урожая хлопка-сырца по сравнению с контролей составила 1,5–7,0 ц/га, предотвращается загрязнение окружающей среды агрохимикатами.

Ключевые слова: УГВ, коллектор, дренаж, субииригации, рост и развитие растение, урожай хлопка-сырца.

There irrigation number decreased up to 1–2, when cotton plants were irrigated in the sub-irrigation method; water was saved up to 987–1880 m³ /hec; number of interrow cultivation was reduced in once; fuel and greasing materials were economized, and there also determined that 1.5–7.0 centner/hec. of additional yield may have been harvested than in control and environmental pollution with agrochemicals may have been controlled.

Key words: Underground water, collector, sub-irrigation, plant growth and development, cotton yield.

INTRODUCTION.

In Uzbekistan, the rapid economic reforms in agriculture are being conducted as in all branches of national economy. This is an incitement to development of cotton, wheat and other crops, which are considered as the main branches in agriculture of Uzbekistan.

In the world agriculture, the particular attention is being paid to reclamation of irrigated lands and effective land use, and water resources, which are considered the main terms of high agricultural crop achievement, especially in cotton yield. In recent years, as the notes of specialists, there are aggravation in reclamative condition of irrigated lands under the influence of irregular water use and increase of salinization in the world.

Nowadays, the 2.32 mln hectare areas (55 percent) of irrigated lands have been salinized in different degrees in Uzbekistan. The most salinization is being occurred by the result of high irrigation rates, also there collectors are of poor quality. In this case, there may be yield decrease from 10 to 90 percent (on various crops) depending on soil salinization degree.

Having checked the time of capillary lifting of soils in different mechanical composition, I. N. Feliciant and M. A. Pankov [1] decided that if where soil layer is thick, there wet capillary lifting will be slower than a low soil layer thickness in spite of the same mechanical composition, because there lifting become slower by air resistance in soil composition.

O. A. Grabovski, P. A. Kerzum and M. A. Pankov [2] recommended the following depth for the composition of approximate mineralized and mineralized underground waters: if the depth of underground water is 0.8–1.0 meter, so chlorine ion in aggregate salts rate in water composition must be 0.17 gr/l, if the depth 1.0–1.50 m — 0.17–0.27gr/l, and also if the depth 1.5–2.5m -2.0–3.0 and 0.27–0.37gr/l.

Nowadays, the water shortage problem of Uzbekistan may be solved by: saving water, full river flows management, technical perfection in irrigation systems, use modern technologies, sowing the water saving type of crops, and introduction (O. Ramazanov, M. Khalmirzaeva, V. Nasonov) [3]

There it should be noted that ideas of the above mentioned scientists are not unanimous, all of them haven’t took a true decision by this time, and also the scientific works in sub-irrigation are extremely few. Thus, it requires more else researches to solve this problem. So, we pursued our object to conduct research works in the Kashkadarya, Samarkand and Fergana regions of the republic.

MATERIALS AND METHODS.

The scientific researches have been conducted during 2006–2008 in the Tura Abdurakhmonov farming economy of Sh. Rashidov farmers’ union in Kashkadarya, and in the Samarkand and Fergana branches of UzSRICG.

There two plots, suiting in soil conditions for each other, have been chosen to thoroughly analyze the problem in finding effective methods for collector water use to improve low mineralized underground water supply in agricultural crops even in the water shortage condition, also for the purpose of collector system regulation.

There field experiments have been conducted on the basis of such methodical guides of UzSRICG as: ”Methods for agrochemical, agrophysical and microbiological experiments in irrigated cotton regions” (SoyuzNIKhI. 1963), “Method for the field experiments on cotton plant” (SoyuzNIKhI. 1981).

RESULTS AND DISCUSSION.

By the method of subirrigation, there have been studied the influence of factors increasing soil fertility and improving reclamative soil condition (moisture accumulating irrigation, application of local and mineral fertilizers) on growth, development and productivity of the crops grown in low salinized, takyr-like, semi-meadow gray soil and meadow soils conditions, there also studied water savings, interrow cultivation and the economy of fuel-greasing materials for cropping. In researches, sub-irrigation timings for Bukhara-8, Akdarya-6 and Buston cotton varieties, which were chosen for experiments, and also agrophysical and agrochemical indices have been worked out.

As the results of researches carried in takyr-like soils of Kashkadarya region, there experimental plot with underground waters in the 1.5–2.0 meters depth, where chosen for sub-irrigation method, have been irrigated three times. So, there irrigation time interval was 29–34 days and water expenditure rate have been formed 3150–3550m³/hectare in the 0–2-1irrigation systems during the vegetation period.

All conditions were the same, but there was need for four-time irrigation in the control variant plots with low underground water depth (2.5–3.0meters) depending on the growth and development. Every irrigation intervals were 21–28 days there. During the vegetation, there 5150–5300 m³/hec. of general irrigation water have been expended, that is, the 1883.3 m³/ hec. of water have been saved there. In August 1, there average plant height was 77.1cm, sympodial branches were 14.3, bolls number was 9.7 including 5.2 of opened in control, but in the variants with sub-irrigation method there: plant height -86.2cm, sympodial branches 15.7, bolls number-13.0 including 4.9 of opened appropriately, that is to say, the higher index than in control have been observed at that method. As a result, cotton yield was 32.9 centner/hectare in control, but it has formed 40.2 centner /hec. in the sub-irrigation variant, so, there 7.3 centner/hec of additional yield have been harvested and 1883.3 m³/hec. of water have been saved, also the cultivation number decreased in once

Having been determined the water mineralization by the special instrument of “Water proof family”, there it was found that, if underground water mineralization had been formed 4.53–4.62 gr/l of dry residue before in early spring and in late autumn (2007), but then its the least rate unit formed 3.64 gr/l in the mid-vegetation period (August). Cotton plant irrigation caused the decrease of underground water mineralization. There being finished vegetation period and stopped irrigation water were the procedures which supplied fall in underground water level, but there remained residue was 3.75 gr and average 4.04 gr in vegetation period. Such detailed information have been also observed during 2006 and 2008. (table 1).

Table 1

Changes in underground water mineralization

рН-soil reaction; mS-soil electrical conductivity; ррt-soil residue.

In the condition of the semi-meadow gray soil soils spread in Samarkand region, cotton plants have been irrigated twice depending on growth and development, and there water expenditure index have been formed 1864 m³/hec. rate during the vegetation, but in the subirrigation, plants have been irrigated once and there water expenditure have been formed 886 m³/hec during the vegetation, so, there water expenditure was 978m³/hec. lower than in control.

In the results of experiment during 2008, there average cotton yield 26.6 centner/hec in control, but it was 28.9 centner/hec in the sub-irrigation variant, so, there 2.3 centner/hec of additional yield have been harvested than in control.

By the results of the three-year experiments, there 27.4 centner/hec of cotton yield have been harvested in control, but in the subirrigation, that index increased up to 30.3 centner/ hec, that is to say, there have been achieved 2.9 centner/hec of additional yield.

According to the agrophysical soil observation on the beginning of vegetation in the meadow soils of Fergana, there volume weight indices were equal to 1.30 gr/cm³ in the 0–30 cm, 1.36 gr/cm³ in the 30–50cm and 1.33 gr/cm³ in the 0–50 cm depths of soil layers.

By the end of the vegetation, those volume weight indices increased even in all conditions; in the control variant, those indices were 1.38gr/cm³ in 0–30cm and 1.43 gr/cm³ in 30–50cm depths of soil layers, but in the subirrigation, those indices formed 1.36 gr/cm³ and 1.41gr/cm³ appropriately.

There less numbers of interrow cultivation were the reason for being light of volume weight. On the beginning of the vegetation, the soil mellowness index was optimal, and then soil was compressed a bit, that is to say, there soil was suitable for growth and development.

In the control variant, there plants were irrigated four times depending on growth and development, and irrigation intervals were 17–25 days. If there water expenditure during the vegetation was 4150m³ /hec. in control, but in the subirrigation, it has been formed 3070 m³/hec with the three time irrigation and 35 days of interval during that period, so, there water expenditure rate was 1080 m³/hec. lower than in control

By the observations, there it has been determined thatunderground water depth levels were: 141cm in May. 25, 145 cm in June. 15, 137 cm in July. 05, 148 cm in July. 15, 158 cm in August. 10 and 160 cm in August. 24 in control variant, but in the subirrigation, those indications formed 146,140,134,135,126 and 126 centimeters appropriately, that is to say, those indications were 3–34 cm higher than in control.

So, in the control variant, there 31.5 centner/hec, in subirrigation, there 33.2 centner/hec of cotton yield have been harvested, that is, there 1.7centner/hec of additional yield have been achieved.

There are no areas with underground waters spread in the depth of until a meter in Kashkadarya, but there are: 0.1 thousand hectare areas with the 1.0–1.5 meter depth, 2.3 thousand hectare areas with the 1.5–2.0 meters depth and 88.9 thousand hectare areas with 2.0–3.0 meter depth of underground waters, by these whole areas, there are 101.5 thousand hectares having until the 1 gr/l rate of and 175.7 thousand hectares area having 1–3 g/l rates of water mineralization (table 2).

Table 2

Effective use of water resources in the sub-irrigation method for cotton plant

In Samarkand, there are 1.6 thousand hectares of underground water area in the depth of until a meter, 6.9 thousand hectares of underground water area in the depth of 1.0–1.5 meters, 27.6 thousand hectares of underground water area in the depth of 1.5–2.0 meters and 83.7 thousand hectares of underground water area in the depth of 2.0–3.0 meters; there underground waters mineralization are until the 1gr/l rate in 357.2 thousand hectare and 1–3gr/l rate in 15.9 thousand hectares area of whole areas.

In Fergana, there are 2.8 thousand hectares of underground water area in the depth of until a meter, 30.1 thousand hectares of underground water area in the depth of 1.0–1.5 meter, 144.9 thousand hectares of underground water area in the depth of 1.5–2.0 meters and 90.8 thousand hectares of underground water area in the depth of 2.0–3.0 meters, and also there underground waters mineralization are until the 1gr/l rate in 114.3 thousand hectares and 1–3 gr/l rate in 173.4 thousand hectares of whole areas.

There are the following districts as: Karshi, Kitob, Shakhrisabz, Kasbi, Chirakchi and Mirishkor in Kashkadarya region, Chelak, Payariq and Akdarya in Samarkand region and Besharik, Furkat, Yozyovon, Altinarik, Akhunbabaev, Dangara and Kuva in Fergana region, where sub-irrigation method is recommended by the foregoing depth and mineralization rates.

CONCLUSION

From the second decade of April to the middle of August, in the nursing period of cotton plant, collectors are blocked, and then opened after the August.15. By the information of many years, there sub-irrigation method is widely recommended in the territories cited above.

As a result of sub-irrigation method, there may be less increase in salt norms, so, soils may be leached with the 1.5–2.5 thousand m³ /hectare of water rate.

ACKNOWLEDGEMENTS

I express my own sincere to Tura Abdurakhmonov farming economy of the Sh. Rashidov farmers’ unit in the Kashkadarya region and the Kashkadarya, Samarkand and Fergana branches of the UzSRICG for their close help in laboratory equipments and technical supply.

References:

1.      Pankov. M.A. 1974. Reclamative Soil science. Tashkent.

2.      Karimov A.Kh., Mirzajonov K. M., Isaev. S. Kh. Increase of productivity in use water resources on farming economies, Water supply: technologies and the social-economic aspects. 2002. Taraz.

3.      Ramazanov O., Khalmirzaeva. M., Nasonov B. 2008. Water shortage in agriculture: problems and salvations //Agro science.Uzbek Agricultural journal