In a situation of increasing water scarcity and growing competition for water of good quality, the role of effective and sustainable management of water for agriculture in seeking to satisfy future demands for food will become ever more important.
The efficiency of water use in agriculture is low, with poor management and inadequate designs the main causes of high water losses resulting in low yields, reduced irrigated areas and environmental problems. To improve water use efficiency a coordinated approach at different levels of the irrigation system is required: at the water source, at the conveyance system and at farm and field level.
Irrigation scheduling is the technique to timely and accurately dose water to the crop and is the key to conserving water, improving irrigation performance and sustainability of irrigated agriculture.
The importance of irrigation scheduling has long been recognized and a substantial part of irrigation research has been directed towards this aspect. A range of scientific and practical tools have been developed to help farmers supply water more accurately to crops. In spite of these efforts, the application of the irrigation scheduling tools in practice has been well below expectations.
The ICID/FAO Workshop on Irrigation Scheduling was organized on the initiative of the ICID Working Group for Sustainable Crops and Water Use with the specific aim to identify the constraints which negatively affect the application of available water saving techniques and to identify solutions which lead to improved irrigation management in practice.
To address the various aspects which play a role in the introduction of and in the successful application of irrigation scheduling, six themes were identified. A total of 80 papers were submitted to substantiate the various issues. The extensive information provided was synthesized in six thematic papers which were presented and discussed during the Workshop, which was held on 12 and 13 September 1995 at FAO Headquarters in Rome on the occasion of the 46th International Executive Council of the International Commission on Irrigation and Drainage.
The main findings of the Workshop can be summarized as follows:
1. Selection of the appropriate irrigation scheduling technique should be based on the specific technology level of the farm and on the conditions of water availability and water supply.
2. Irrigation scheduling techniques and models need to differentiate according to the irrigation method used. Monitoring and improving the performance of the irrigation method should be part of an integrated package to improve irrigation management at farm level.
3. Under conditions of limited water supply, salinity and variable rainfall, accurate irrigation scheduling techniques need to be used to minimize yield reductions and to optimize sustainable use of available water.
4. A process of interactive communications and participatory research involving researchers, system managers, extension workers and farmers is needed to successfully adopt scientific scheduling methods.
5. Most collective irrigation systems cannot adopt crop-based and water saving methods. Modernization of the irrigation system is required to provide flexible water delivery and greater autonomy for the users.
6. Effective irrigation scheduling and water delivery require rules and regulations for flexible water allocation which are determined by a set of social, cultural and institutional conditions.