Analysis of cotton water productivity in Fergana Valley of Central Asia

Cotton water productivity was studied in Fergana Valley of Central Asia during the years of 2009, 2010 and 2011. Data was collected from 18 demonstration fields (13 in Uzbekistan, 5 in Tajikistan). The demonstration field farmers implemented several improved agronomic and irrigation water management practices. The average values of crop yield, estimated crop consumptive use (ETa) and total water applied (TWA) for the demonstration sites were, respectively, 3700 kg/ha, 6360 m3/ha, and 8120 m3/ha. The range of values for TWA and ETa were, respectively, 5000 m3/ha to 12,000 m3/ha and 4500 m3/ha to 8000 m3/ha. A quadratic relationship was found between TWA and ETa. The average yield of the adjacent fields was 3300 kg/ha, whereas the average yield of cotton in Fergana Valley as a whole was 2900 kg/ha, indicating 28% and 14% increase in crop yield, respectively, from, demonstration fields and adjacent fields. There was no significant difference in crop yields between the wet years (2009 and 2010) and the dry year (2011), which is explained by the quadratic relationship between TWA and ETa. The water productivity values ranged from 0.35 kg/m3 to 0.89 kg/m3, indicating a significant potential for improving water productivity through agronomic and irrigation management interventions. The ratio of average ETa divided by average TWA gave an average application efficiency of 78% (some fields under-irrigated and some fields over-irrigated), the remaining 22% of water applied leaving the field. Since more than 60% of the water used for irrigation in Tajikistan and Uzbekistan is pumped from, even if all this 22% of water returns to the stream, substantial energy savings would accrue from improving the average application efficiency at field level. The range of values for TWA indicates the inequity in water distribution/accessibility. Addressing this inequity would also increase water productivity at field and project level

Determining optimal groundwater table depth for maximizing cotton production in the Sardarya Province of Uzbekistan

Poor on-farm irrigation practices and rising groundwater table depths are the major reasons for low cotton yields in the Sardarya province of Uzbekistan. To ensure sustainability of cotton production in the area, precise calculations of irrigation requirements are needed to optimize crop yields and to keep groundwater table depth below the root zone to avoid soil salinization. To determine optimal groundwater table depth and irrigation amounts for the Sardarya province of Uzbekistan, the Soil-Water-Atmosphere-Plant (SWAP) model was used. SWAP was calibrated and validated using measured data from an experimental cotton field during the agricultural year of 2006 and 2007. The calibrated SWAP model was then used to simulate optimal groundwater table depth and irrigation amounts. The simulation results show that for the existing conditions in the study area, a groundwater table depth of approximately 200 cm together with an irrigation application of 2500m3 ha1 will be the most appropriate combination for optimal cotton yields ( 3.0 t ha1). However, to achieve maximum potential yields of cotton (5-6 t ha1), leaching of excessive salts from the root zone through freshwater application would be imperative. This would require rehabilitation of the existing drainage network in the area

Evaluation of furrow irrigation practices in Fergana Valley of Uzbekistan

The performance of furrow irrigation systems in terms of application efficiency, runoff ratio, and water requirement efficiency were evaluated at nine different sites within the Provinces of Fergana (6 sites) and Andijon (3 sites) in Uzbekistan. A total of 46 irrigation events were evaluated during the year 2009, whereas only a total of 8 irrigation events (at 3 sites) were evaluated during the year 2010. Most of the selected fields have slopes greater than 0.005; hence, the average runoff volume from these fields was 39% of the total volume of water applied to the fields, indicating problems with selection of appropriate furrow flow rates under the given set of field conditions. For several fields, the seasonal volume of water applied was significantly different than the irrigation norms specified for the site. Though some of the farmers followed the irrigation advisory service on when to irrigate, there was a large mismatch between the volume of water applied and the volume of water deficit within the crop root zone. Reliability, in terms of magnitude and duration of flow rate received at the fields, was a major issue at all the sites. Considerable fluctuations were observed in the flow rates received at all the field sites during each irrigation event. In addition, the average flow rate received at the field sites varied considerably between irrigation events making it difficult for farmers to manage irrigation water. Farmers that had high watertable (less than 100 cm from the ground surface) still applied large volumes of water, resulting in low application efficiency. Several recommendations for improving the performance of furrow irrigation systems in Uzbekistan are provided

An innovative public-private partnership for irrigation extension in Fergana Valley of Central Asia

A 'farmer-centric' innovative institutional mechanism, a public-private partnership, was created and strengthened, in the Fergana valley of Central Asia, for facilitating communication between farmers and researchers, and to disseminate knowledge on improved agronomic and irrigation management practices to improve water productivity at field level. As a result, yields of cotton from the twenty five demonstration sites in the three countries of Fergana valley - Kyrgyzstan, Tajikistan and Uzbekistan - were, on the average, 28% higher than the average yield of cotton in the valley, suggesting that the proposed institutional mechanism was very effective in dissemination of information to farmers. Yields from neighboring farmers of demonstration fields were 14% higher than the average yields. In addition, demonstration site farmers used, on the average, 20% less water than the non-project farmers. Two independent external reviewers stated that this innovative public-private mechanism was very effective in disseminating information on improving water productivity at plot level to farmers, and suggested that the focus in the future should be on devising effective policy and economic instruments for financial sustainability of the innovation cycle after the donor support is withdrawn

Prediction of improved water productivity on-farm level in the selected cotton farms of Fergana and Andijan Provinces of Uzbekistan

In Proceedings of the Republican Scientific Practical Conference on Efficient Agricultural Water Use and Tropical Issues in Land Reclamation, Tashkent, Uzbekistan, 10-11 November 2010. Tashkent, Uzbekistan: Ministry of Agriculture and Water Resources; Tashkent, Uzbekistan: International Water Management Institute; Tashkent, Uzbekistan: Scientific Information Center of Interstate Commission for Water Coordination (SANIIRI)Irrigated agriculture in Central Asia can only be developed through increase of crop yields and reduction of water volumes applied per unit of agricultural production. Thus to improve agricultural production, proper agronomic measures and irrigation schedules have to be developed considering local conditions. To assess existing water productivity, 9 farms have been selected along South Fergana Canal. A Soil-Water-Air-Plant (SWAP) model has been applied for the same fields to predict potential water productivity

Water productivity of potato under improved irrigation techniques in Uzbekistan

Potato is a very important cash crop in Uzbekistan as the government has implemented several measures to increase its production to meet food security as well as to improve its export potential. However, irrigation water demand of potato is much higher than for other crops such as sorghum and maize, which normally consume less water and generate more income. Furrow irrigation is the main irrigation method used to grow potato in Uzbekistan. Introduction of improved irrigation methods could reduce the water used for potato production and provide alternative solutions to improving potato production and income security under water scarce conditions. There are few comparative studies on conventional furrow versus improved irrigation methods for potato production. This paper explores water productivity of two varieties of potato under four irrigation treatments in Andijan and Ferghana regions of Uzbekistan. At each location, four different irrigation treatments were evaluated. These four treatments were: conventional furrow irrigation (CFI), high frequency furrow irrigation (HFI), partial root zone drying irrigation (PRD), and drip irrigation (DrI). The experimental sites in each study area were established in 2012 on farmer fields. Data on water used and agronomic performance were collected from both study sites to calculate water productivity for each treatment. Analysis of Variance (ANOVA) was used to identify differences in treatments. The results indicate that, overall, high frequency furrow irrigation and drip irrigation treatments performed better than conventional furrow irrigation and partial root drying treatments. Research findings from this paper are useful for relevant stakeholders in Uzbekistan whose population is highly dependent on irrigated agriculture. Existing water use policies in Uzbekistan do not provide water users incentives for water saving as water delivery for agriculture is highly subsidized by the government resulting in excessive water use. These findings may help reduce unsustainable water use by increasing knowledge of relevant stakeholders including decision makers in order to improve water policies in the region

Growing cotton in Karshi Steppe, Uzbekistan: water productivity differences with three different methods of irrigation

In Uzbekistan, generally practiced methods of irrigating crops are varieties of flooding (basin, border and furrow). These practices have created problems of waterlogging, salinity and lower irrigation efficiency. Waterlogging and salinization already affect 50 percent of irrigated areas, and irrigation efficiency hardly reaches up to 50-60%. The Karshi Steppe of Kashkadarya region is among the prime cotton and wheat producing areas in Uzbekistan, using around 4.5 – 5.0 billion m3 of irrigation water within a hydrological year. About 75% of this water is abstracted from Amu Darya River in the territory of Turkmenistan and raised up to 135 meters, using a cascade of seven pumping stations to Karshi main canal. Research on implications of applying other irrigation technologies with different irrigation regimes on cotton crop are limited in Uzbekistan, especially under water scarce situations, such as in Karshi Steppe. This study targeted that knowledge gap and compared performance of cotton crop under different irrigation regimes with three technologies (furrows, gated pipes, and drip). The yield data ranged from 3.5 to 4.6 t ha-1, whereas water productivity (WP) values ranged from 0.44 to 1.20 kg m-3 and irrigation water use efficiency (IWUE) ranged from 0.51 to 1.41 kg m-3. The measured ranges of IWUE and WP are much wider compared with data available for Karshi Steppe. Due to cotton being sensitive to soil-moisture stress, lack of skillful technicians at site for irrigation scheduling has led to more water stress than was planned for, resulting in lower crop yields than expected