Methods for Assessing Agricultural Water Productivity and Efficiency

Recent concern over food prices has triggered a renewed interest in agricultural production systems. While attention is focused mainly on cropping, a complete analysis of food production systems should recognise the importance of livestock as major consumers of resources – in particular water – and as providers of food and other products and services. We propose that there is a need to examine not just food systems in isolation, but combined food and water systems, both of which are described as in a critical condition. From this broader perspective, it appears even more important to understand livestock systems because first, a total evaluation of agricultural water productivity – the gain from water consumed by agriculture – cannot be made without understanding the complexities of livestock-containing systems and; second, because in most tropical river basins, livestock systems are the major consumers of water. To identify total water productivity of livestock-containing systems, we describe concepts of agricultural water productivity and review the complexities of tracking the flow of water through livestock-containing systems: from inputs as evapotranspiration (ET) of forage and crops to outputs of valued animal products or services. For the second part, we present preliminary results from water use accounts analysis for several major river basins, which reveal that for Africa at least, livestock systems appear to be the major water consumers. Yet, little is known about the fate of water as it passes through these systems. We propose that livestock-containing systems offer substantial scope for increasing total water productivity and that there is considerable merit in improving the capacity to analyse water consumption and water productivity through such systems. Without removing this major source of uncertainty, the potential for systemic improvement to meet the world food and water crisis remains undefined and hence under-acknowledged.

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Impact of changing cropping pattern on the regional agricultural water productivity

The Journal of Agricultural Science ◽

10.1017/s0021859614000938 ◽

2014 ◽

Vol 153 (5) ◽

pp. 767-778 ◽

Cited By ~ 6

Author(s):

S. K. SUN ◽

P. T. WU ◽

Y. B. WANG ◽

X. N. ZHAO

Keyword(s):

Water Scarcity ◽

Crop Production ◽

Water Footprint ◽

Water Productivity ◽

Irrigation District ◽

Cropping Pattern ◽

Agricultural Water ◽

Cropping Patterns ◽

Cash Crops ◽

The Impact

SUMMARYWater scarcity is a major constraint of agricultural production in arid and semi-arid areas. In the face of future water scarcity, one possible way the agricultural sector could be adapted is to change cropping patterns and make adjustments for available water resources for irrigation. The present paper analyses the temporal evolution of cropping pattern from 1960 to 2008 in the Hetao Irrigation District (HID), China. The impact of changing cropping patterns on regional agricultural water productivity is evaluated from the water footprint (WF) perspective. Results show that the area under cash crops (e.g. sunflower and melon) has risen phenomenally over the study period because of increased economic returns pursued by farmers. Most of these cash crops have a smaller WF (high water productivity) than grain crops in HID. With the increase of area sown to cash crops, water productivity in HID increased substantially. Changing the cropping pattern has significant effects on regional crop water productivity: in this way, HID has increased the total crop production without increasing significantly the regional water consumption. The results of this case study indicate that regional agricultural water can be used effectively by properly planning crop areas and patterns under irrigation water limitations. However, there is a need to foster a cropping pattern that is multifunctional and sustainable, which can guarantee food security, enhance natural resource use and provide stable and high returns to farmers.

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Internal and external green-blue agricultural water footprints of nations, and related water and land savings through trade

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-8-483-2011 ◽

2011 ◽

Vol 8 (1) ◽

pp. 483-527 ◽

Cited By ~ 13

Author(s):

M. Fader ◽

D. Gerten ◽

M. Thammer ◽

J. Heinke ◽

H. Lotze-Campen ◽

...

Keyword(s):

Water Productivity ◽

Virtual Water ◽

Green Water ◽

World Population ◽

Agricultural Water ◽

Water Flows ◽

Increase Food Production ◽

Per Capita ◽

Water Volumes ◽

Biosphere Model

Abstract. The need to increase food production for a growing world population makes an assessment of global agricultural water productivities and virtual water flows important. Using the hydrology and agro-biosphere model LPJmL, we quantify at 0.5° resolution the blue (irrigation water) and green (precipitation water) virtual water content, i.e. the inverse of water productivity, for 11 of the world's major crop types. Based on these, we also quantify the water footprints (WFP) of all countries, for the period 1998-2002, distinguishing internal and external WFP (virtual water imported from other countries) and their blue and green components, respectively. Moreover, we calculate water savings and losses, and for the first time also land savings and losses, through international trade with these products. The consistent separation of blue and green water flows and footprints, which is needed due to the different sources and opportunity costs of these two water pools, shows that green water globally dominates both the internal and external WFP (84% of the global WFP and 94% of the external WFP rely on green water). Accordingly, some of the major exporters of the crops considered here (e.g. Argentina, Canada) export mainly green virtual water, but traditional rice exporters such as India and Pakistan mainly export blue virtual water. The external WFPs are found to be relatively small (6% of the total global blue WFP, 16% of the total global green WFP). Nevertheless, current trade saves significant water volumes and land areas (~263 km3 and ~41 Mha, respectively, equivalent to 5% of the sowing area of the crops considered here and 3.5% of the annual precipitation on this area). Linking the proportions of external to internal blue/green WFP with the per capita WFPs allows recognizing that only a few countries consume more water from abroad than from their own territory and have at the same time above average WFPs. Thus, countries with high levels of per capita water consumption affect mainly the water situation in their own country.

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A Multi-Objective Hierarchical Model for Irrigation Scheduling in the Complex Canal System

Sustainability ◽

10.3390/su11010024 ◽

2018 ◽

Vol 11 (1) ◽

pp. 24 ◽

Cited By ~ 7

Author(s):

Shanshan Guo ◽

Fan Zhang ◽

Chenglong Zhang ◽

Chunjiang An ◽

Sufen Wang ◽

...

Keyword(s):

Decision Making ◽

Optimization Model ◽

Water Productivity ◽

Critical Factor ◽

Water Shortage ◽

Irrigation Scheduling ◽

Agricultural Water ◽

Canal System ◽

Multi Objective ◽

Wide Range

Abstract: Due to population growth, environmental pollution and climate change, the lack of water resources has become a critical factor which threatens sustainable agricultural development. Reasonable irrigation scheduling strategies can reduce the waste of water and enhance agricultural water-use efficiency. In the present study, the decomposition-coordination theory was adopted to analyze the hierarchical canal system. A novel nonlinear multi-level multi-objective optimization model for complex canal systems was established, taking account of the multiple demands from decision makers and realistic factors of canal operation. An interactive method of the technique for order preference using similarity algorithm and genetic algorithm was proposed to solve the developed model. The developed model was successfully applied for the operational strategy making of a canal system located in the arid area of northwest China. The results indicated that the optimization model could help shorten the operational duration by two days, achieve about 26% reduction of irrigation water consumption, and improve the efficiency of water delivery from 0.566 to 0.687. That will be very favorable for the promotion of the agricultural water productivity, the relief of water shortage crisis and the sustainable development of agriculture. The outcomes can provide a wide range of support for decision making and make irrigation decision-making more scientific and systematic.

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