Совершенствование технологии возделывания и семеноводства картофеля в предгорных и засоленных почвенных условиях Узбекистана

Аннотация

Topicality and demand of the subject of dissertation. In order to increase the potato yields on a regular basis in the republic, it is required to constantly improve its technologies of agricultural cultivation. New varieties of potato require specific agricultural technologies in different soil and climatic conditions. One of the main factors of increasing the yield and gross production in potato growing is the introduction of new modem seed growing systems. In conditions of the saline lands in Uzbekistan, special attention must be paid to the adoption of new technologies in the production of potato cultivation in view of the soil and climatic conditions. Solving the above mentioned problems require improvement of existing agricultural technologies of potato cultivation. It is important to adopt evidencebased seed systems into the production. The cultivation of selection of potato varieties with economically valuable traits and properties, finding new ways of planting and growing plants, determining methods of optimization requirements of plants to soil moisture and nutrients arc of great theoretical and practical significance. In 1991, 351.2 thousand tons of potato was produced in Uzbekistan only, in 2013 the potato yields constituted 2,250.3 thousand tons of potato, harvested from 78.2 thousand ha of land. The average yield of potato constituted 21.0 t ha'1. Currently, the actual potato production is 75 kg per capita only, and so, it cannot meet the demand for this product. According to the medical prescriptions, it is recommended to consume on average 90 kg year'1 of potato. Therefore, to meet the requirements of the population of Uzbekistan, a production of 2.7 Mln. t year'1 of potato is necessary. A demand for the present scientific work can be explained by its response to the issues raised by the Cabinet of Ministers in the Decree № 274 at 27.06.2001 “On additional measures to improve potato seed farming” aimed at improving the technology of potato production, organizing seed farming and fully providing the farmers and private household producers with high quality seeds. This decree was put into operation with the purpose to improve the technology of potato production, organization of seed farming, sufficient provision of farmers and dchkhans with high quality seed materials. Increasing potato yields by widespread introduction of new technologies into practice and production of high-quality seed materials arc nowadays pressing issues. Establishing a system of seed potatoes in the territory of the Bakhmal district, Djizak province corresponds the priority directions of scientific research carried out in the republic. In the foothills, the viral disease of potatoes is rarely observed, and establishing science-based seed production in these areas is an advanced direction. Purpose of researches arc includes a development of improved potato cultivation technology and a seed farming system, providing increased and high-quality yields of food and seed potato in the foothill areas of Uzbekistan, as well as developing a new advanced method of assessment of salt tolerance of potato varieties and their implementation into a production. Scientific novelty of the dissertation research arc the followings: the development of a new technology of food and seed potato production in conditions of the Bakhmal district located in the foothill zone of Uzbekistan; a development of a new modern elite potato seed cultivation method, which lasts 4 years instead of traditional 6 years, was developed. The potato plants produced under this new technology arc observed to be less susceptible to viral diseases, and provide high quality and quantity yields. Seeding potato using the scheme of 70x15 cm, with the stand density of up to 95 thousand plants per ha and conducting varietal cleaning four times arc proved to be an effective approach; the system, consisting of main methods of potato cultivation technology and methods of assessment of salt tolerance of potato varieties to obtain high quality and quantity yields has been developed for conditions of light and moderately saline soils of the Hungry Steppe; scientifically proved that the improved irrigation method, which prevents soil salinization during potato cultivation, has been developed. In this method, the length of the furrows should be 50 m, duration of irrigation 10-12 m, optimal soil moisture levels 75-75-85 % from field moisture holding capacity and the irrigation scheme of 1-2-6. CONCLUSION 1. To cultivate food potato in the foothill zone of Uzbekistan in spring and summer, the early-ripening varieties Ostara, Kuvonch-16/56'", mid-early ripening varieties Binclla, Santc, Condor, Bakhro-30 and mid-ripening varieties Hamkor 1150, Diamant, Cardinal arc considered suitable. Cultivation of potato in spring (April, 1 till 5th) and in summer (June, 1 till 5th) using planting scheme of 70x20 cm and 3.9 t ha'1 of seeds allows obtaining a yield of 25-30 t ha'1. 2. Potato cultivation in the foothill zones during growing period includes: manual (spade) soil processing (to a depth of 6-8 cm) at the time of shoots advent, 1 soil tillage after full appearance of shoots (depth 12-14 cm) and making of furrows, and conducting 2 spade soil processing, 2 soil tillage and furrow reshaping in the beginning of the budding phase. In the end of a budding phase earthing of plants with a special equipment and weeding till the end of a growing season arc conducted. In typical sierozems, application of 40 t ha'1 of semidecomposed manure and mineral fertilizers N22oPi65K-i25 kg ha'1, will result in the quantity and quality of a crop yield within the requirements of a modern agriculture with the additional crop yield of 8.6 t ha'1 compared with control. 3. In foothill zone of Uzbekistan, the potato planting in spring and maintaining soil moisture of about 75-75-85 % from field moisture holding capacity, the irrigation scheme of 1-2-5 promotes increased crop yield of 6.3 t ha'1 compared with control. During planting in summer with the irrigation scheme of 2-2-6, provision of pre-irrigation soil moisture level within 75-75-85 % provides additional yield of 10.6 t ha'1 compared with control. 4. In the foothill zone of Uzbekistan, to produce a high-quality seed material it is necessary to conduct culling of healthy plants using a method of individual clonal selection accounting for morphological characteristics and productivity indicators. A comparative study showed that a new shortened 4-ycar method of elite seed production performs better compared with a traditional 6-ycar method. It is shown that by testing of clones during only one year and without establishing of super-super elite nursery, the potato seed-farming activities in foothill areas can be conducted within 4 years and high-quality seeds can be produced. 5. In seed-farming nurseries, the increase of reproduction of healthy tubers is achieved by planting of tubers with a weight of 30-50 grams by a scheme of 70x15 cm and stand density of 95 thousand plants ha'1. Cutting tubers of 80-100 grams into two and of 120-150 grams into 4 parts raises a net reproduction from 1.5 to 3.6 times. 6. For conditions of chloridc-sulphatc type of moderately saline soils of the Hungry Steppe, the following spring-planted early-ripening varieties arc suitable: Ostara, Kuvonch 16/56M, mid-early ripening varieties Bincllc, Karatop, Aladin, Bakhro-30, mid-ripening varieties Hamkor 1150. Diamand, Cardinal. For the late planting in summer, mainly mid-ripening varieties Binclla, Karatop, Aladin, Bakhro-30 and mid-ripening varieties Hamkor 1150, Diamant, Cardinal arc suitable. 7. The agronomical tolerance of potato to salinity is 0.020-0.022 % of Cl ion and the norm of biological stability of 0.04-0.05 %. In the conditions of the soil salinity of Hungry steppe the good results arc received by planting potato in spring as soon as possible till March, 1st, and in summer from June, 20th till July, 10th. The optimum scheme of potato planting is 70x20 cm. 8. Under chloridc-sulphatc type conditions of moderately saline soils of Hungry steppe in order to improve planting technology, good yields arc obtained by planting of seed tubers of 30-80 grams without splitting in spring to a depth of 7-8 cm, in summer to a depth of 15-16 cm with application of 2 cm thick mulch of semi-decomposed manure. In an advanced cultivation technology it is required to conduct 1st soil tillage before appearance of shoots, the 2nd tillage - during full appearance of shoots, the 3ld tillage in a budding phase properly and timely during soil maturity after water application and earthing of plants by soil, weeding during plant growth. 9. In saline soil conditions of Hungry steppe and under fertilizer application technology of early potato in moderately saline soils, the recommended annual amount of fertilizer application is 40 t ha’1 of scmi-dccomposcd manure + N|5oPii2KS5. When the pre-irrigation soil moisture is 75-75-85 % from field moisture holding capacity and application of irrigation by a scheme of 1 -2-6 it is possible to achieve the crop yield of 26.2 t ha'1. With the furrow length of 50 meters and duration of water application of 10-12 hours, the optimum soil moisture is achieved and water from wetted soil layers docs not reach the groundwater and thus, the secondary salinization is avoided. 10. Development of the potato salt tolerance assessment methods and defining indicators of these methods has been conducted as follows: field germination capacity of the whole seed tubers should be not less than 95 % in the early planting dates and not less than 92 % in summer; the number of stems in one plant should be more than 8.5, the productive, tuber-forming stems more than 6.0; the volume and mass of roots during a blooming phase should be above 140 cm3 and 130 grams, in the end of vegetation above 45 smJ and 40 grams, respectively; the quantity of stems in one plant should be more than 3, mass of plant tops more than 400 grams, a yield of tubers more than 600 grams and a number of tubers more than 6; marketable productivity of plants in early planting dates should be above 25-27 t ha'1, in summer planting above 22 t ha'1, degraded tubers not more than 1 %. 11. Application of advanced potato cultivation technology in foothill zones of Uzbekistan can provide the potato yield of 30 t ha'1 and 4.5-5.0 million soum ha' 1 of a net profit. Application of complex agro-tcchnology under the modern shortened 4-ycar method of a high-quality seed production promotes the productivity increase by 10.0-10.5 t ha'1, and thus, net profit reception by 15.0-15.5 million soum ha'1 compared with a traditional 6-ycar scheme of seed-farming. In the conditions of Hungry steppe, the introduction of advanced technology promotes the possibility of receiving additional yield of 8.0-8.5 t ha'1 and thus, 3.0-3.5 million in soum ha'1 of a net profit compared with the traditional technology. 12. The following recommendations arc suggested for implementation of the advanced potato cultivation technology in the foothill zones of Uzbekistan based on the obtained results: planting of early-ripening varieties Binella, Kuvonch-16/65M, mid-early ripening varieties Aladin, Bakhro-30, mid-ripening Hamkor-1150, Diamant and Romano in spring during 1 till 5th of April and in summer in 1 till 5th of June, with the planting scheme of 70x20 cm and amount of seed tubers 3.9 t ha'1. ; the potato cultivation works during growing period consist of superficial manual (spade) soil processing (to a depth of 6-8 cm) during the advent of shoots, 1st soil tillage following a full appearance of shoots (to a depth of 12-14 cm) and making of furrows, 2nd manual soil processing during budding phase, 2nd soil tillage and making of furrows. In the end of a budding phase the earthing of plant stems is conducted using special earthing maker; on typical sierozem soils, the amounts of fertilizer application should be within 40 t ha'1 of semi-decomposed manure + N220P165R125 kg ha'1, pre-irrigation soil moisture in spring of 75-75-85 % from field moisture holding capacity with the water application scheme of 1-2-5, and in summer 75-75-85 % from field moisture holding capacity and 2-2-6, respectively. The following technology of production of high-quality seed materials in foothill zones of Uzbekistan is recommended: to produce elite seeds, it is recommended to use a new shortened 4-ycar method and to increase a net reproduction of healthy tubers in seed-farming nurseries, to plant seed in the scheme of 70x15 cm with tubers of 30-50 grams and stand density of 95 thousand plants per ha. The following recommendations arc suggested for introduction of an advanced potato cultivation technology in conditions of moderately saline soils of Hungry steppe: the following varieties arc recommended for planting in spring: early-ripening varieties Binclla,and Kuvonch-1656m, mid-early ripening varieties Condor, Aladin, Bakhro-30 and mid-ripening varieties Hamkor-1150, Diamant, for summer planting mid-early ripening varieties Binclla, Condor, Bakhro-30 and midripening varieties Hamkor-1150, and Diamant. Planting potato in spring is recommended to be made till 1st of March, in summer from 20th of June till 10th of July under the plot size of 70x20 cm and with application of seeds of 3.9 t ha'1. It is necessary to plant the whole (uncut) tubers of 30-80 grams in spring to a depth of 7-8 cm and in summer to a depth of 15-16 cm. After planting introduction of mulch into a soil surface with semi-decomposed manure of not less than 2 cm thick is recommended.