Irrigation efficiency depending on water cost

The article provides an analytical review of the achieved crop yields under irrigation in experimental and production conditions. For today, the best production experience in the use of irrigated land indicates that, subject to all agrotechnical requirements, the yield of early grain crops reaches 8-10 t / ha, corn - 10-14 t / ha, oilseeds - 4-6 t / ha, vegetable crops - over 60 t / ha, which is about 90% of their productivity achieved in the experiments of scientific institutions. The comparative assessment of grain production in different climatic zones of Ukraine for the period of the most intense climatic change shows that over the past thirty years, the share of grain production in the Steppe zone has decreased from 45 to 35% of the total in Ukraine. The analysis of service cost for the transportation of water for irrigation in the southern regions of Ukraine is given. It was revealed that, despite a unified standard method for calculating the cost of water transportation, its price varies significantly by operational units of the State Agency for Water Resources of Ukraine. The main factors of fluctuations in the cost and fees for the transportation services of water for irrigation are the budgetary funding level of operating organizations, providing these services, the number of water transfers, the volume of actual irrigation on irrigated lands, the share of irrigated areas in the service area. The economic assessment of irrigation efficiency when having different water and other technological costs, taking into account the depreciation of capital investments, indicates that having a water price of 4,0-5,0 UAH/m3, the gross profit from growing the most profitable field crops is 35-40 % higher than the efficiency in rainfed agriculture. At the cost of water is 3,0-3,5 UAH/m3 and the use of the production capacity of the inter-farm irrigation network by 60-70%, financial prerequisites will be created for the effective operation of these networks.

The Water-Energy-Food-Ecosystem Nexus in the Mediterranean: Current Issues and Future Challenges

The Mediterranean is an area where the balance between water demand and abstractions vs. water availability is often under stress already, as demonstrated here with the Water Exploitation Index. In this work, model estimates on how different proposed measures for water resources management would affect different indicators. After a review of the current water resources status in the Mediterranean and the definition of indicators used in this study, aspects interlinked with water in the Water-Energy-Food-Ecosystems Nexus are briefly discussed, focusing on problems linked with water scarcity and depletion of groundwater resources as well as with climate change projections. Subsequently, the proposed measures for water efficiency are detailed—irrigation efficiency, urban water efficiency, water reuse and desalination—that might be effective to reduce the growing water scarcity problems in the Mediterranean. Their effects that result from the LISFLOOD model, show that wastewater reuse, desalination and water supply leakage reduction lead to decreased abstractions, but do not affect net water consumption. Increased irrigation efficiency does decrease consumption and reduces abstractions as well. We deduct however that the current envisaged water efficiency measures might not be sufficient to keep up with the pace of diminishing water availability due to climate change. More ambition is needed on water efficiency in the Mediterranean to keep water scarcity at bay.

Assessing effects of climate change on irrigation water demand in the Lombok River Basin, Indonesia

Irrigation water demand in the command area is affected by rainfall and climate conditions in the river basin. In climate change conditions, rainfall and temperature are predicted to increase and projected to impact irrigation water requirements significantly. Therefore, understanding the climate change effects on irrigation demand in the command area is significant to the river basin manager and planner for managing water resources effectively. This study aims to predict the impact of climate change and irrigation efficiency improvement on the irrigation water requirement in 2032-2040. This study used the CropWat model to estimate irrigation water requirements in 1995-2005 and 2032-2040. Irrigation water demand in the Dodokan watershed as a part of the Lombok river basin was computed using the historical rainfall and climate data from observation stations. Further, the observed data from 2006 to 2014 were projected into climate change in 2032-2040 as an input for the model to predict the demand in corresponding years. Result suggests that the change of annual irrigation water demand in the Dodokan watershed was expected to rise by 1.61% in 2032-2040 compared with 1995-2005, and irrigation efficiency improvement effort would decrease the demand -18.18% in the climate change period.

Performance of community-based water-saving technology under land fragmentation: evidence from groundwater overexploitation in the North China Plain

The current water shortage crisis has necessitated an increased focus on improving the irrigation efficiency in groundwater overdraft areas. Consequently, the Chinese government has supported small farmers in installing community-based water-saving technologies (WSTs) providing high irrigation efficiency. Based on the data collected from 620 households located in the groundwater overdraft area of Hebei, North China Plain, this study conducts a stochastic frontier analysis to measure farmers' irrigation water use efficiency (WUE) and analyzes the impact of land fragmentation and WST types on their WUE. The results show that the average WUE of groundwater irrigation is 0.606. The WUE between community-based and household-based WSTs differs based on the degree of land fragmentation. A high degree of land fragmentation restricts community-based WSTs from efficiently improving farmers' WUE, whereas household-based WSTs perform better and are easier to adopt. For high land fragmentation, the WUE of the community-based WST is 9.12% lower than that of the household-based WST. However, the WUE of the community-based WST is 12.55% higher than that of the household-based WST when the degree of land fragmentation is low. Therefore, the government should pay attention to small farmers' adaptability toward WST and promote community-based WSTs on a low degree of land fragmentation.

Assessing the Impact of Irrigation Efficiency Projects on Return Flows in the South-Eastern Murray–Darling Basin, Australia

Improving irrigation efficiency (IE) is an approach used globally to help meet competing demands for water and facilitate reallocation of water between sectors. In the Murray–Darling Basin in Australia, the Australian government has invested heavily in IE projects to recover water for the environment. However, this approach has been seriously questioned, out of concerns that improved IE would reduce irrigation return flows to rivers and therefore offset water recovery. In this study, we use a water balance model to assess the impact of the IE projects on return flows and highlight sensitivities and uncertainties. The model enables the impact on return flows to be assessed on specific IE projects and regional characteristics. Overall, reductions in return flows are estimated to be less than 20% of the total proposed IE savings. The history of IE in the southern MDB has meant that most of the current reductions are in ground return flows. Our estimate is much lower than two previous studies, mainly due to different assumptions being used on groundwater connectivity between irrigation areas and major streams. While the IE projects significantly reduce seepage to groundwater (with off-farm and on-farm projects reducing seepage by 19% and 53% of total savings respectively), not all seepage reductions will translate to a reduction in ground return flows to rivers. A lower estimate is consistent with existing monitoring and groundwater modeling studies. In this paper, the study results are discussed in a broader context of impacts of IE projects on volumes and salinity of streams and groundwater resources.