Integrated management of water resources demand and supply in irrigated agriculture from plot to regional scale

Niels Schütze,Michael Wagner

doi:10.5194/piahs-373-51-2016

Abstract

Abstract. Growing water scarcity in agriculture is an increasing problem in future in many regions of the world. Recent trends of weather extremes in Saxony, Germany also enhance drought risks for agricultural production. In addition, signals of longer and more intense drought conditions during the vegetation period can be found in future regional climate scenarios for Saxony. However, those climate predictions are associated with high uncertainty and therefore, e.g. stochastic methods are required to analyze the impact of changing climate patterns on future crop water requirements and water availability. For assessing irrigation as a measure to increase agricultural water security a generalized stochastic approach for a spatial distributed estimation of future irrigation water demand is proposed, which ensures safe yields and a high water productivity at the same time. The developed concept of stochastic crop water production functions (SCWPF) can serve as a central decision support tool for both, (i) a cost benefit analysis of farm irrigation modernization on a local scale and (ii) a regional water demand management using a multi-scale approach for modeling and implementation. The new approach is applied using the example of a case study in Saxony, which is dealing with the sustainable management of future irrigation water demands and its implementation.

Highlights

Arid and semi-arid areas that are intensively used for agriculture, are facing water shortage which is often intensified by an overexploitation of existing water resources
The estimation of water productivity (WP) for limited water availability is difficult on a regional level because the performance of irrigation systems depend on a number of factors such as climate conditions, grown crops, soil hydraulic characteristics and used irrigation systems
For a regional analysis of future development of irrigation water demand and local self-sufficiency in Saxony the spatial resolution for estimating stochastic crop water production functions (SCWPF) depending on local climate conditions, grown crops, soil hydraulic characteristics and used irrigation systems is 5 by 5 km

Summary

Introduction

Arid and semi-arid areas that are intensively used for agriculture, are facing water shortage which is often intensified by an overexploitation of existing water resources They show an increased sensitivity to water stress and a high vulnerability that can only be reduced by a highly efficient and foresighted water resource management practices. The improvement of WP needs a good quantitative understanding of the relationship between irrigation practices and grain yield, i.e. the crop water production function (CWPF). With this knowledge, the value of each unit of water applied to a field can be estimated and compared with alternative uses within and beyond the agricultural sector. The stochastic properties of the relevant climate factors (e.g. precipitation and temperature) and of the soil properties have to be considered in a risk-based regional water manage-

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Conclusion