Irrigated agriculture provides 40% of the world's crop-based foods but often with a negative impact on the environment. It is important to recognize that in addition to providing food and fibre, irrigation and controlled drainage systems can be optimized to provide additional ecosystem services and mitigate climate change by using resources in a more efficient way. Contemporary case studies were identified from around the world, including flood control by paddy fields in Japan, water quality enhancement and wastewater reuse in South Africa and Taiwan, micro-/meso-climate regulation in Ethiopia and Japan, controlled drainage and sub-irrigation to maximize carbon sequestration and minimize leaching in Finland, and groundwater table management to reduce irrigation water and pumping requirements in Turkey. Irrigation infrastructure, such as rice paddy terraced landscapes (Japan) and large dams and canals (Australia), have also achieved notable additional ecotourism job creation. Case studies were analysed in terms of funding opportunities and compared using the Common International Classification of Ecosystem Services system. It is recommended that planning frameworks be developed that seek to optimize ecosystem services such as the ones discussed above. Policy should be updated to recognize these services and provide incentives to irrigators and water management entities accordingly.
‘Tackling water scarcity in agriculture’, which is the theme of the 25th Congress of the International Commission on Irrigation and Drainage (ICID), is at the crux of the global challenge of ensuring a climate-resilient and water- and food-secure world for future generations. The Asian region faces significant threats due to its high vulnerability to climate change impacts and growing food insecurity and water stress across many river basins. The Asian Development Bank (ADB) is stepping up assistance in line with the international commitments by the multilateral financial institutions. There are significant opportunities that are tapped to address this theme, including (i) exploring and replicating highly successful experiences of enhancing irrigated agriculture productivity manifold as seen in the Indian states of Chhattisgarh, Karnataka and Madhya Pradesh and in other South Asian countries; (ii) reinvigorating efforts to operationalize integrated water resources management in river basins; (iii) adopting new technologies, such as remote sensing and automation, and digital technologies, including artificial intelligence; and (iv) pursuing institutional and financing innovations. Resources of ADB and other multilateral institutions can be utilized to develop and demonstrate successful innovations before they are replicated by the own sources of the developing countries.
Climate change (CC) could lead to many crises. Therefore, increasing the number of cultivated varieties represents a low-cost factor in confronting this problem. The effect of the genotype × environment (G × E) interaction on yield stability was estimated for 28 new sesame lines in the Beni Suwef, El-Beheira and El-Menoufia governorates in Egypt across 15 environments from 2019 to 2022 using AMMI analysis. The SALTMED model was used to predict the yield of sesame plants under five increasing air temperature scenarios (CC factor) to obtain future projections of sesame yield to determine the lines that are most genetically stable and facing CC. Variance analysis revealed significant differences in yield between the G and E groups and between the G × E interaction group. Fifteen genotypes yielded better control, and C6.4, C5.8 and C9.6 were selected as genetically stable according to AMMI analysis. The SALTMED model predicted that the yields of lines C3.8 and C6.2 were not affected under the high-temperature scenarios across the three governorates, moreover lines C1.8, C2.3, and, C6.12 productions were not affected under Beni Suwef and El-Beheira governorates. of lines C1.8, C2.3 and C6.12 were also not affected by the Beni Suwef or El-Beheira governorates. It is now possible to establish a hybridization programme in sesame that combines parents with high productivity and high resilience to CC.
The main goal in water efficiency in agriculture is to obtain more products with the same amount of water. In this respect, the use of irrigation performance indicators is important for increasing agricultural water efficiency. This study was conducted to evaluate agricultural water efficiency in the Konya closed basin, which is the region most affected by drought in Turkey. For this purpose, performance indicators selected for evaluating agricultural water efficiency were determined in irrigation associations taken as material for the years 2016–2020.
In the research area, the following water use efficiency indicators were determined: annual amount of irrigation water distributed 1.750–517.462 million m3 yr⁻¹ (MCM yr⁻¹), annual amount of irrigation water distributed per unit area 0.529–8.688 MCM ha⁻¹, annual amount of irrigation water distributed per unit irrigated area 0.787–33.909 MCM ha⁻¹ and annual water supply ratio ranging between 0.220 and 52.600. The following agricultural water efficiency performance indicators were determined: income obtained for unit irrigation area, 127–5075 US$ ha⁻¹; income obtained per unit irrigated area, 656–12353 US$ ha⁻¹; income obtained per unit irrigation water taken into the network, 0.104–6.771 US$ m⁻3; and income obtained per unit irrigation water consumed, 0.236–37.358 US$ m⁻3. Correlation analysis was carried out to identify the significance of the relationships between the performance indicators, and the results were discussed.
This paper proposes a simple method for determining drip lateral length in relatively flat fields in which minor losses are not considered and a uniform emitter flow rate is assumed. This makes it possible to derive a useful relationship in a closed form to determine drip lateral length according to the Hazen–Williams and Blasius resistance equations. An important advantage of the proposed procedure for determining drip lateral length is that it helps users establish the characteristics of the commercial emitters that they should select, an issue that has been poorly addressed in the past. Finally, after deriving this new solution, the same relationship is extended to a case in which minor losses are considered, and the uniform emitters' flow rate assumption is relaxed. The results of all input data sets show that when neglecting minor losses, the relative error between the inlet pressure head estimated with the suggested procedure and that calculated with the exact numerical method is less than 2.5%. However, when minor losses are considered, the number of emitters must not exceed 300 to obtain this threshold error. Several applications are performed, showing the reliability of this new design procedure.
India receives an annual precipitation of about 3880 BCM and the average water availability is 1999 BCM. Out of this, utilizable water resources are 1126 BCM due to topographic constraints, distribution effects and so forth. In India, agriculture remains the principal source of livelihood for about 54.6% of the population. The overall water demand of the country in 2010 was estimated at 710 BCM, of which the water use in irrigation was about 557 BCM (78%). With limited water resources available for fulfilling the water requirement of all the sectors, it is projected that by 2050 our overall water demand (1180 BCM) would outgrow the total utilizable water resources, namely 1126 BCM. Moreover, the groundwater table in various regions of the country is seeing a decline at an alarming rate.
Additionally, climate change poses significant and far-reaching threats in all spheres of life and the economy. The erratic rainfall pattern makes a significant contribution to the frequent occurrence of floods and droughts in the country.
This paper attempts to put in context the impact of climate change observed on various facets of water resources, the need to develop and invest in climate-resilient water infrastructure, and to highlight several initiatives taken by the government of India in this direction.
Effective drainage is a crucial factor in paddy fields, especially in regions with waterlogging or heavy clay soils. Identifying an effective drainage system is essential for the successful removal of excess soil water from paddy fields to prepare them for subsequent crops. This study aimed to evaluate three different drainage systems, shallow surface drainage (shallow ditch), conventional subsurface pipe drainage and trench-type subsurface drainage (French drain), in paddy fields in terms of drainage water volume, water table depth, drainage intensity, soil moisture and cracks. Experiments were carried out in a physical model capable of simulation with a 7.5 m drain spacing. The findings indicated that trench-type drainage was more effective in reducing soil moisture due to its higher drainage water volume compared to other systems. The time required for the topsoil to reach its lower plastic limit in the subsurface, trench-type and shallow surface drainage systems was 14, 11 and 15 h after the depletion of excess water over the soil surface, respectively. Although shallow surface drainage represented faster depletion of excess water, trench-type drainage eventually proved to be the most effective alternative for providing appropriate qualifications for secondary cultivation. Crack areas on the soil surface were twice as extensive in trench-type and subsurface drainage systems as in shallow surface drainage systems, indicating their superior performance.
In arid regions, harvesting floodwater can mitigate irrigation-induced groundwater depletion by providing additional surface water and recharging aquifers. We designed an experimental protocol to quantify these fluxes on a date farm located along the Wadi Satt, whose flow originates from the Anti-Atlas Mountains in south-eastern Morocco. Automatic barometric sensors were used to monitor the water level in a 6500 m3 floodwater harvesting pond and in surrounding boreholes. Six flood events occurred from 2021 to 2023. The pond water balance indicated that most stored water is pumped for irrigation (56% of harvested floodwater). More than 40% infiltrates at a rate of approximately 90 mm day−1, and the remainder evaporated. Analytical modelling of the pond water table system showed that the radius of the piezometric mound resulting from pond infiltration is less than 360 m. Groundwater recharge from the irrigated plot could be observed after two close floods that enabled continuous pumping for several weeks, suggesting that in this specific context, over-irrigation using surface water allows the aquifer to be recharged. The hydrological effects of possible future expansion of these ponds at the watershed scale should be analysed to assess possible negative impacts on downstream water resources.
This review paper addresses challenges in the water sector, particularly in irrigated agriculture, aiming to propose solutions for meeting irrigation demands while promoting global food security and sustainable development, notably SDG 6. Structured around three facets: empowering farmers, strengthening conventional sources of irrigation water and harnessing non-conventional water resources, it emphasizes the significance of exploring blue water resources due to precipitation variability. Many irrigation systems operate below efficiency, offering productivity enhancement opportunities. Water management in agriculture spans various levels, involving farmers as key stakeholders. In addition to surface water, alternative sources like rainwater, grey water, recycled wastewater and groundwater can meet irrigation needs. Rainfed agriculture, facing challenges from erratic rainfall, can benefit from rainwater harvesting and under-irrigation practices. Wastewater emerges as a pivotal resource, particularly in periurban areas, necessitating appropriate safety measures. This paper presents the General Report of Congress Question 64 of the ICID Congress in Visakhapatnam. It provides a unique opportunity to focus on how alternative water resources might enhance the resilience of irrigation systems and bridge the gap between water supply and demand. The subdivision of the paper into three distinct subtopics guides research contributions, encouraging responses that delve into the specific themes of reinforcing, harnessing and empowering, all within the context of sustainable irrigated agriculture.
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