Pasquale Steduto

Food and Agriculture Organization of the United Nations | FAO ·  Natural Resources Department

FAO Water Reports No.46

Higher efficiency rarely reduces water consumption

Crop simulation models are valuable tools for quantifying crop yield response to water, and for devising strategies to improve agricultural water management. However, applicability of the majority of crop models is limited greatly by a failure to provide open-access to model source code. In this study, we present an open-source version of the FAO A...

Résumé Au moment où l’agriculture méditerranéenne souffre de la pénurie d’eau et de grandes lacunes en termes de productivité et de connaissances, ce que traduit un gaspillage permanent de nourriture et de ressources, les scénarios d’avenir sur la distribution de l’eau semblent confirmer qu’une action sur plusieurs plans doit nécessairement être en...

We compare 27 wheat models' yield responses to interannual climate variability, analyzed at locations in Argentina, Australia, India, and The Netherlands as part of the Agricultural Model Intercomparison and Improvement Project (AgMIP) Wheat Pilot. Each model simulated 1981–2010 grain yield, and we evaluate results against the interannual variabili...

The data set includes a current representative management treatment from detailed, quality-tested sentinel field experiments with wheat from four contrasting environments including Australia, The Netherlands, India and Argentina. Measurements include local daily climate data (solar radiation, maximum and minimum temperature, precipitation, surface...

Many simulation studies have been carried out to predict the effect of climate change on crop yield. Typically, in such study, one or several crop models are used to simulate series of crop yield values for different climate scenarios corresponding to different hypotheses of temperature, CO2 concentration, and rainfall changes. These studies usuall...

Crop models of crop growth are increasingly used to quantify the impact of global changes due to climate or crop management. Therefore, accuracy of simulation results is a major concern. Studies with ensembles of crop models can give valuable information about model accuracy and uncertainty, but such studies are difficult to organize and have only...

621 F ollowing the 2007–2008 and 2011 food price crises, renewed concerns over food security have surfaced, in both middle-and high-income regions. In response, the commercial pressures on land are increasing globally 1,2 . Meanwhile access to water is a con-cern, with an ever-increasing number of people affected by water shortages 3 . Energy deman...

Projections of climate change impacts on crop yields are inherently uncertain. Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate. However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop sim...

Projections of climate change impacts on crop yields are inherently uncertain. Uncertainty is often quantified when projecting future greenhouse gas emissions and their influence on climate. However, multi-model uncertainty analysis of crop responses to climate change is rare because systematic and objective comparisons among process-based crop sim...

This paper discusses climate, land, energy and water (CLEW) interactions in Burkina Faso. It shows that integrated assessments of resource use at the national level can provide important insights and benefits, especially for a resource constrained least developed country. Agricultural policy is shown to have strong implications for energy use, wher...

This short chapter presents the main agrophysiological characteristics of the quinoa crop in terms of its water requirements, drought and cold resistance, and grain productivity.

In its broadest sense, water productivity (WP) is the net return for a unit of water used. Improvement of water productivity aims at producing more food, income, better livelihoods and ecosystem services with less water. There is considerable scope for improving water productivity of crop, livestock and fisheries at field through to basin scale. Pr...

Irrigation is widely criticised as a profligate and wasteful user of water, especially in watershort areas. Improvements to irrigation management are proposed as a way of increasing agricultural production and reducing the demand for water. The terminology for this debate is often flawed, failing to clarify the actual disposition of water used in i...

The AquaCrop model was developed to replace the former FAO I&D Paper 33 procedures for the estimation of crop productivity in relation to water supply and agronomic management in a framework based on current plant physiological and soil water budgeting concepts. This paper presents the software of AquaCrop for which the concepts and underlying prin...

This work compares the performance of AquaCrop, a crop simulation model developed by FAO, with that of two well established models, CropSyst and WOFOST, in simulating sunflower (Helianthus annuus L.) growth under different water regimes in a Mediterranean environment. The models differ in the level of complexity describing crop development, in the...

This article introduces the FAO crop model AquaCrop. It simulates attainable yields of major herbaceous crops as a function of water consumption under rainfed, supplemental, deficit, and full irrigation conditions. The growth engine of AquaCrop is water‐driven, in that transpiration is calculated first and translated into biomass using a conservati...

The first crop chosen to parameterize and test the new FAO AquaCrop model is maize (Zea mays L.). Working mainly with data sets from 6 yr of maize field experiments at Davis, CA, plus another 4 yr of Davis maize canopy data, a set of conservative (nearly constant) parameters of AquaCrop, presumably applicable to widely different conditions and not...

Given the current pressures to reduce irrigation water use, it is important to optimize the use of water in irrigated agriculture. This work was aimed at determining the optimum level of applied irrigation water (AIW) for cotton (Gossypium hirsutum L.) production in southern Spain under several climatic and agricultural policy scenarios. To generat...

The modeling of yield response to water is expected to play an increasingly important role in the optimization of crop water productivity (WP) in agriculture. During 3 yr (2004–2007), field experiments were conducted to assess the crop response to water stress of quinoa (Chenopodium quinoa Willd.) in the Bolivian Altiplano (4000 masl) under differe...

Accurate crop development models are important tools in evaluating the effects of water deficits on crop yield or productivity. The FAO AquaCrop model predicts crop productivity, water requirement, and water use efficiency (WUE) under water‐limiting conditions. A set of conservative parameters [calibrated and validated for maize (Zea mays L.) in a...

Predicting attainable yield under water-limiting conditions is an important goal in arid, semi-arid and drought-prone environments. To address this task, FAO has developed a model, AquaCrop, which simulates attainable yields of the major herbaceous crops in response to water. Compared to other models, AquaCrop has a significantly smaller number of...

Growing crops for biofuels is often criticized because of its direct competition for land for food production. The recent price increases on world food markets are partly a result of this competition. For instance, cereals prices have increased by more than 60% since 2005 and in 2006 sugar prices peaked at a level twice as high as the level of prev...

SUMMARY - Estimating attainable yield under water-limiting conditions remains central in arid, semi-arid and drought-prone environments. To address this need, FAO has been developing a yield-response to water model, AquaCrop , which simulates attainable yields of the major herbaceous crops. As compared to other crop models, AquaCrop has a significa...

Nitrate leaching is one of the many forms of environmental pollution resulting from irrigation and intensive agriculture. In this work, a method of combining an agronomic simulation model (EPIC) and a mathematical multi-objective programming model is used to analyse the effects of three agricultural policies on farmer’s revenue and nitrate leaching...

As the competition for the finite water resources on earth increases due to growth in population and affluence, agriculture is faced with intensifying pressure to improve the efficiency of water used for food production. The causes for the relatively low water use efficiency in agriculture are numerous and complex, including environmental, biologic...

The ever-increasing demand and competition for the finite water resource worldwide call for more efficient use of water in all sectors, including firstly agricultural food production. One important consideration is the existence of a limit to the amount of biomass a crop can produce per unit of water consumed. This article analyzes the theoretical...

Half of the world food production originates from irrigated and drained soils. Advanced soil water flow simulation models have the potential to contribute to the solution of relatively complex problems in irrigation and drainage science and management, provided that field data are available to calibrate and run them. Besides providing a literature...

Land degradation and desertification represents one of the most striking sets of processes affecting the Mediterranean Region causing persistent deterioration of the physical, chemical and biological properties of the land components, especially the soil. Land degradation, then, results in loss of overall productivity, which in turn impairs sustain...

Continued development of networks of electronic weather stations worldwide has increased the availability of weather data for calculating ETo on an hourly basis. There has been question and debate as well as studies on the appropriate expression and parameterization for the surface resistance (rs) parameter of the Penman-Monteith (PM) equation and...

Water use efficiency (w) is a crop parameter of outstanding importance in crop simulation models, derived here as the slope of the relationship linking crop carbon gain to cumulative transpiration. This study aims at: (i) evaluating w of field-grown sunflower, sorghum, wheat and chickpea, at three levels of aggregation—day-time net assimilation (A)...

Radiation use efficiency (ɛ) is a crop parameter widely used in crop simulation models, derived here as the slope of the relationship linking crop carbon gain to cumulative intercepted solar radiation. Our objectives were to: (i) determine ɛ of field-grown sunflower, sorghum, wheat and chickpea, at three levels of aggregation—day-time net assimilat...

The effects of 2 irrigation intervals (If1: 7 days and If2: 14 days), 4 nitrogen doses (Ng, N0, N1, N2 and N3) and 2 crop coefficients (Kpc1: 0.60 and Kpc2: 0.90) on pistachio nut fertigation were studied to establish suitable irrigation and fertigation scheduling. The nitrogen levels were 0, 10, 15 and 20 mg L-1. In the traditional treatment, Ng,...

The book objectives: Identifying dominant land degradation factors in the Mediterranean region, assessing their extend and intensity throughout the region and at each participating country of the Project; Identifying major gaps in information and knowledge base to reach a proper regional understanding of sustainable land management; Implementing ef...

The present work aims at testing the hypothesis that carbon use efficiency (CUE) of sunflower, grain sorghum, wheat and chickpea crops, having different photosynthetic pathways (C3, C4) and yield composition (carbohydrates, proteins, lipids), will hold constant over the natural thermal regime occurring during the entire crop cycle in the open field...

¶The performance of the Penman-Monteith (PM) equation to estimate daily reference evapotranspiration (ETO) was investigated by attributing three distinct features to the canopy resistance (r c): (i) r c constant at 70 s m−1 (Allen et al., 1998; FAO Irrigation and Drainage Paper n. 56), (ii) r c variable as linear function of a critical resistance r...

The whole Mediterranean is facing desertification, scarcity of water resources, urbanisation, salinisation and alkalinity, soil erosion, and massive landslides. It is widely accepted among concerned scientists and decision-makers that soil science and in particular pedology, could play a crucial role in reducing these negative effects. The new mill...

An automated transient-state closed-system canopy-chamber for gas-exchange determinations of field-crops was developed to allow unattended day and night, high frequency CO2 and H2O exchange measurements, with short measurement time (15 s) and high scanning rate (0.5 s). Environment tests on the chamber performance indicated that: atmospheric pressu...

This work describes the development, operational functionalities and spatial modeling applications of a Geographic Information Systems (GIS)-based irrigation management system, to be used by irrigation consortia and local governmental institutions. The system provides tools for the exploration of spatially-referenced databases relevant for irrigati...

This study aimed at comparing actual water consumption of cotton obtained by the water balance method under full and limited irrigation conditions, with that estimated by a micrometeorological method (energy balance). Which is being widely used nowadays. Results indicated that in the first year the total irrigation water applied was 438 mm. Whereas...

Sunflower (Helianthus annuus) was grown in both open-field and outdoor potted conditions in Southern Italy, and irrigated with water having electrical conductivity ranging between 0.9 and 15.6 dS m(-1) obtained by different NaCl concentrations. The aim of the work was to study the leaf area and photosynthetic responses of sunflower to mild salt str...

Little is known about the response of sweet sorghum to water stress. Therefore, the aim of this study was to characterize sweet sorghum physiological water use efficiency (WUE) under progressing water stress conditions, with emphasis on the canopy scale as compared with the leaf scale. Sweet sorghum (Sorghum bicolor (L.) Moench) was subjected to tw...

The degree of coupling between the plant canopy and the atmosphere is indicative of the ability of the two systems to exchange momentum, energy, and mass. In terms of water vapor and CO2 exchange, it characterizes the extent to which stomatal and canopy conductance may control transpiration and CO2 assimilation. In the present work, the degree of c...

Photosynthesis of individual leaves and canopies in relation to transpiration has been studied fairly extensively with chambers, which, unfortunately, alter the environment of the plant. Scaling up remains a problem and there are only limited data on simultaneously measured water vapor and CO2 fluxes of crop canopies, especially comparing treatment...

The feasibility of determining at 5-min intervals the fluxes of water vapor and CO2 using a Bowen ratio/energy balance/CO2 gradient (BREB+) apparatus was studied. Details of the BREB+ apparatus are given. The results obtained over maize canopies at the short 5-min signal averaging time are examined in several aspects. One aspect is the fact that on...

Seasonal course of evapotranspiration and of canopy CO2 assimilation are determined by interactions among the plant, aerial, and soil factors over time and culminate in the total water requirement and primary productivity of a crop. In this study, maize was grown for two seasons in large fields under two contrasting soil water regimes (WET and DRY)...

The feasibility of determining at 5-min intervals the fluxes of water vapor and CO2 using a Bowen ratio/energy balance/CO2 gradient (BREB+) apparatus was studied. Details of the BREB+ apparatus are given. The results obtained over maize canopies at the short 5-min signal averaging time are examined in several aspects. One aspect is the fact that on...

Photosynthetic water-use efficiency of leaves (WUE1) and canopy (WUEc) of sweet sorghum (Sorghum bicolor [L.] Moench) was investigated to gain insight into the crop ability to optimize water use and to provide explanations for the high values of biomass WUE reported in the literature. The Keller cultivar was grown for two consecutive years (1993 an...

Water is not a renewable resource. Its total amount on the earth is fixed and its allocation in space and time is governed by the hydrological cycle, on which human intervention plays an important role. Then, if the ever declining quantity of available water to agriculture is faced, while the agricultural yield needs to be sustained, a proportional...

Sweet sorghum is considered a new industrial crop in Mediterranean environment where it might become an alternative source of energy. In order to evaluate the risk deriving from the introduction of sweet sorghum in this area, its agronomical behaviour is analyzed in this paper by estimating for four years the total amount of radiation intercepted b...

This paper describes a Bowen ratio/energy balance (BREB) system which, in conjunction with an infra-red gas analyzer (IRGA), is referred to as BREB+ and is used to estimate evapotranspiration (ET) and net CO2 flux (NCF) over crop canopies. The system is composed of a net radiometer, soil heat flux plates, two psychrometers based on platinum resista...

Half of the world food production originates from irrigated and drained soils. However, the future management of these systems must accept the paradigm shift away from managing abundant water supplies (with focus on conveyance and distribution) and toward the beneficial use of scarce water resources with the emphasis on deficit irrigation, sustaina...

levelled to slightly sloping, with more than 60% of territory below 200 m above sea level. The high and steep land zones are located only in NE (Gargano) and NW (Sub-Apennian Dauno) with several peaks of more than 1,000 m above sea level. Five physiographic units may be distinguished in the Apulia region. Three of them (Sub-Apennian Dauno, Tavolier...

SUMMARY - Effective management of scarce water resources requires a systems approach. A quantitative framework, termed the chain of efficiencies concept, was described in the previous meeting of WASAMED and proposed for use in the analysis of water use efficiency of production systems. Starting at the source of water, a cascade of events leads to t...

An account is given of the assessment of physiological water use efficiency for the complete characterization of citrus biodiversity is given. This approach may allow to link "genetic" and "field" issues thus inducing the farmers to take sounder actions. Leaf gas-exchange measurements are applied by a portable photosynthesis system, which needs to...