Climate change impacts on crop water productivity in Africa using a multi-model inter-comparison

2020 ◽  
Author(s):  
Imeshi Weerasinghe ◽  
Celray James Chawanda ◽  
Ann van Griensven
Keyword(s):  
Climate Change ◽  
Crop Yield ◽  
Crop Yields ◽  
Water Productivity ◽  
Baseline Scenario ◽  
Crop Water ◽  
Yield Data ◽  
Water Vapour Flux ◽  
Crop Models ◽  
Crop Water Productivity

<p>Evapotranspiration (ET) or the water vapour flux is an important component in the water cycle and is widely studied due to its implications in disciplines ranging from hydrology to agricultural and climate sciences. In the recent past, growing attention has been given to estimating ET fluxes at regional and global scales. However, estimation of ET at large scales has been a difficult task due to direct measurement of ET being possible only at point locations, for example using flux towers. For the African continent, only a limited number of flux tower data are openly available for use, which makes verification of regional and global ET products very difficult. Recent advances in satellite based products provide promising data to fill these observational gaps.</p><p>In this study we propose to investigate the Climate Change (CC) impact on crop water productivity across Africa using ET and crop yield predictions of different crop models for future climate scenarios. Different model outputs are evaluated including models from both the ISI-MIP 2a and 2b protocols. Considering the problem of direct observations of ET being difficult to obtain, especially over Africa, we use ET estimates from several remotely sensed derived products as a references to evaluate the crop models (maize) in terms of magnitude, spatial patterns and variations between models. The crop model results for crop yield are compared to FAO reported crop yields at country scale. The results show a very strong disagreement between the different crop models of the baseline scenario and when compared with ET and crop yield data.  Also, a very large uncertainty is obtained for the climate change predictions. It is hence recommended to improve the crop models for application in Africa.</p>

scholarly journals Accessing future crop yield and crop water productivity over the Heihe River basin in northwest China under a changing climate

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Qi Liu ◽  
Jun Niu ◽  
Bellie Sivakumar ◽  
Risheng Ding ◽  
Sien Li
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Crop Yield ◽  
Water Productivity ◽  
Heihe River Basin ◽  
Future Climate Change ◽  
Heihe River ◽  
Crop Water ◽  
Crop Water Productivity ◽  
The Heihe River Basin

AbstractQuantitative evaluation of the response of crop yield and crop water productivity (CWP) to future climate change is important to prevent or mitigate the adverse effects of climate change. This study made such an evaluation for the agricultural land over the Heihe River basin in northwest China. The ability of 31 climate models for simulating the precipitation, maximum temperature, and minimum temperature was evaluated for the studied area, and a multi-model ensemble was employed. Using the previously well-established Soil and Water Assessment Tool (SWAT), crop yield and crop water productivity of four major crops (corn, wheat, barley, and spring canola-Polish) in the Heihe River basin were simulated for three future time periods (2025–2049, 2050–2074, and 2075–2099) under two Representative Concentration Pathways (RCP4.5 and RCP8.5). The results revealed that the impacts of future climate change on crop yield and CWP of wheat, barley, and canola would all be negative, whereas the impact on corn in the eastern part of the middle reaches of the Heihe River basin would be positive. On the whole, climate change under RCP8.5 scenario would be more harmful to crops, while the corn crops in the Minle and Shandan counties have better ability to cope with climate change.

scholarly journals A multi-model analysis of teleconnected crop yield variability in a range of cropping systems

2019 ◽  
Author(s):  
Matias Heino ◽  
Joseph H. A. Guillaume ◽  
Christoph Müller ◽  
Toshichika Iizumi ◽  
Matti Kummu
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Food System ◽  
Crop Yields ◽  
Southern Oscillation ◽  
Yield Variability ◽  
Management Scenarios ◽  
Yield Data ◽  
Climate Oscillations ◽  
Crop Models

Abstract. Climate oscillations are periodically fluctuating oceanic and atmospheric phenomena, which are related to variations in weather patterns and crop yields worldwide. In terms of crop production, the most widespread impacts have been observed for the El Niño Southern Oscillation (ENSO), which has been found to impact crop yields in all continents that produce crops, while two other climate oscillations – the Indian Ocean Dipole (IOD) and the North Atlantic Oscillation (NAO) – have been shown to impact crop production especially in Australia and Europe, respectively. In this study, we analyse the impacts of ENSO, IOD and NAO on the growing conditions of maize, rice, soybean and wheat at the global scale, by utilizing crop yield data from an ensemble of global gridded crop models simulated for a range of crop management scenarios. Our results show that simulated crop yield variability is correlated to climate oscillations to a wide extent (up to almost half of all maize and wheat harvested areas for ENSO) and in several important crop producing areas, e.g. in North America (ENSO, wheat), Australia (IOD & ENSO, wheat) and northern South America (ENSO, soybean). Further, our analyses show that higher sensitivity to these oscillations can be observed for rainfed, and fully fertilized scenarios, while the sensitivity tends to be lower if crops are fully irrigated. Since, the development of ENSO, IOD and NAO can be reliably forecasted in advance, a better understanding about the relationship between crop production and these climate oscillations can improve the resilience of the global food system to climate related shocks.

scholarly journals Drops for crops: modelling crop water productivity on a global scale

2013 ◽  
Vol 10 (3) ◽  
pp. 295-300
Keyword(s):  
Crop Yield ◽  
Food Policy ◽  
Water Productivity ◽  
Global Scale ◽  
Fertilizer Management ◽  
Crop Water ◽  
Crop Growth Model ◽  
Crop Water Productivity ◽  
Maize Yields ◽  
Good Agreement

There is an emerging need to support water and food policy and decision making at the global and national levels. A systematic tool that is capable of analyzing water-food relationships with high spatial resolutions would be very useful. A GEPIC model has recently been developed by integrating a crop growth model with a Geographic Information System (GIS). The GEPIC model was applied to simulate crop yield and crop water productivity (CWP) for maize at a spatial resolution of 30 arc-minutes on a global scale. A comparison between simulated yields and FAO statistical yields in 124 countries shows a good agreement. The simulated CWP values are mainly in line with the measured values reported in literature. The crop yield and CWP were simulated with the assumption of sufficient water and fertilizer supply, holding other factors unchanged. The simulation results show that many countries have the potentials in achieving high maize yields and CWP. More than 80% of African countries have the potential to double their CWP. This reflects the current poor water and fertilizer management there. The results imply that efforts have to be strengthened to improve water and fertilizer management should the malnutrition be reduced or even eliminated.

Managing water resources in Libya through reducing irrigation water demand: more crop production with less water use

2013 ◽  
Vol 44 ◽  
pp. 95-102
Author(s):  
Saad Ahmad Alghariani
Keyword(s):  
Water Use ◽  
Water Demand ◽  
Crop Production ◽  
Crop Yields ◽  
Agricultural Research ◽  
Water Productivity ◽  
National Level ◽  
Crop Water ◽  
Irrigation Water Demand ◽  
Crop Water Productivity

AbstractThe looming water crisis in Libya necessitates taking immediate action to reduce the agricultural water demand that consumes more than 80% of the water supplies. The available information on water use efficiency and crop water productivity reveals that this proportion can be effectively reduced while maintaining the same, if not more, total agricultural production at the national level. Crop water productivity, which is depressingly low, can be doubled through implementing several measures including relocating all major agricultural crops among different hydroclimatic zones and growth seasons; crop selection based on comparative production advantages; realisation of the maximum genetically determined crop yields; and several other measures of demand water management. There is an urgent need to establish the necessary institutional arrangements that can effectively formulate and implement these measures as guided by agricultural research and extension services incorporating all beneficiaries and stakeholders in the process.

scholarly journals A multi-model analysis of teleconnected crop yield variability in a range of cropping systems

2020 ◽  
Vol 11 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Matias Heino ◽  
Joseph H. A. Guillaume ◽  
Christoph Müller ◽  
Toshichika Iizumi ◽  
Matti Kummu
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Food System ◽  
Crop Yields ◽  
Southern Oscillation ◽  
Yield Variability ◽  
Management Scenarios ◽  
Yield Data ◽  
Climate Oscillations ◽  
Crop Models

Abstract. Climate oscillations are periodically fluctuating oceanic and atmospheric phenomena, which are related to variations in weather patterns and crop yields worldwide. In terms of crop production, the most widespread impacts have been observed for the El Niño–Southern Oscillation (ENSO), which has been found to impact crop yields on all continents that produce crops, while two other climate oscillations – the Indian Ocean Dipole (IOD) and the North Atlantic Oscillation (NAO) – have been shown to especially impact crop production in Australia and Europe, respectively. In this study, we analyse the impacts of ENSO, IOD, and NAO on the growing conditions of maize, rice, soybean, and wheat at the global scale by utilising crop yield data from an ensemble of global gridded crop models simulated for a range of crop management scenarios. Our results show that, while accounting for their potential co-variation, climate oscillations are correlated with simulated crop yield variability to a wide extent (half of all maize and wheat harvested areas for ENSO) and in several important crop-producing areas, e.g. in North America (ENSO, wheat), Australia (IOD and ENSO, wheat), and northern South America (ENSO, soybean). Further, our analyses show that higher sensitivity to these oscillations can be observed for rainfed and fully fertilised scenarios, while the sensitivity tends to be lower if crops were to be fully irrigated. Since the development of ENSO, IOD, and NAO can potentially be forecasted well in advance, a better understanding about the relationship between crop production and these climate oscillations can improve the resilience of the global food system to climate-related shocks.

Validation of Aquacrop for Different Irrigation Regimes of Onion (Allium Cepa) in Bontanga Irrigation Scheme

2018 ◽  
Vol 1 (1) ◽  
pp. 1-12
Author(s):  
Y. K. Agbemabiese ◽  
A-G Shaibu ◽  
V. D. Gbedzi
Keyword(s):  
Allium Cepa ◽  
Crop Yield ◽  
Water Productivity ◽  
Leaf Biomass ◽  
Crop Water ◽  
Irrigation Scheme ◽  
Crop Water Productivity ◽  
Irrigation Regimes ◽  
Aquacrop Model ◽  
Mean Square Errors

Crop water productivity models are important tools in evaluating the effect of different irrigation regime on crop yield. AquaCrop model is a crop water productivity model adopted by the Land and Water Division of FAO in the year 2009. It simulates yield response to water for herbaceous crops, and it is particularly suitable in addressing conditions where water is a key limiting factor in crop production such as in northern Ghana. The objective of this study was to calibrate the AquaCrop model for different irrigation regimes for onion (Allium cepa), to determine its effect on crop growth and yield parameters of the crop at the Bontanga irrigation scheme. To achieve these, the Randomised Complete Block Design (RCBD) was used on Red Creole onion variety. RCBD was made up of four irrigation treatment regimes, 117%, 100%, 80% and 60% crop water requirements (CWR) of onion, with five replicates. Results indicated that there was no significant variation in yield, dry bulb biomass and total biomass, but there was difference for dry leaf biomass of onion at 0.05 significance level. The AquaCrop model simulated satisfactorily the crop yield, biomass and evapotranspiration water productivity of onion. There was a strong correlation and a significant linear relation between the simulated and measured crop yield, biomass and evapotranspiration water productivity. Validation of AquaCrop model using Nash-Sutcliffe efficiency (E), Root mean square errors (RMSE) and index of agreement (d) showed that, AquaCrop model can be used to simulate CWR of bulb crops, such as onion.

scholarly journals Conservation Tillage and Nutrient Strategies Enhances Crop-Water Productivity and Economic Profitability of Wheat (Triticum Aestivum L)

2021 ◽  
pp. 41-51
Author(s):  
Pradeep Kumar Singh ◽  
R. K. Naresh ◽  
. Vivek ◽  
Yogesh Kumar ◽  
M. Sharath Chandra ◽  
...  
Keyword(s):  
Soil Fertility ◽  
Management Practices ◽  
Nutrient Management ◽  
Crop Yields ◽  
Water Productivity ◽  
Conservation Agriculture ◽  
Wheat Crop ◽  
Crop Water ◽  
Crop Establishment ◽  
Crop Water Productivity

Decline in soil fertility is one of the major constraints to sustainable crop production and profitability. To meet the increasing demand for the growing population the issue of low soil fertility needs to be addressed moreover, excessive pumping of groundwater over the years to meet the high irrigation water requirement of rice-wheat system has resulted in over exploitation of groundwater in the Indo-Gangetic plains (IGP) of India. Replacement of traditional wheat cultivation practices under conservation agriculture (CA) based management (tillage, and crop establishment management) practices are required to promote sustainable agriculture. Furthermore, inefficient nutrient management practices are responsible for low crop yields and nutrient use efficiencies in wheat under rice-wheat cropping system (RWCS). A field experiment was conducted at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (U.P.), India to evaluate the effects of tillage and crop establishment (TCE) methods, and nutrient management practices on crop yields, water productivity and profitability of wheat under RWCS. The main plot treatments included four combinations of TCE [Furrow irrigated raised beds (FIRB), Roto tillage (RT), Reduced tillage (RTW) and conventional tillage (CT), with six nutrient management practices [N1 Control, N2 100% Recommend Dose of Fertilizer, N3 100% RDF + NPK consortia + Bio-stimulant, N4 75% RDF + NPK consortia + Bio-stimulant, N5 100% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation, and N6 and 75% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation]. Crop water productivity and net returns under FIRB were significantly increased by 11.7% and 13.8% compared to CT respectively, during year of experimentation. Study showed that conservation agriculture based sustainable practices (FIRB) and nutrient strategies 100% RDF + NPK consortia + Bio-stimulant + NPK (18:18:18) spray after II irrigation approach provided opportunities for enhancing crop and water productivity, and profitability of wheat crop in North-West IGP of India. Treatments with N and conservation agriculture were the most profitable. A combined use of conservation agriculture and organic and chemical fertilizers is the best bet for increasing, wheat crop yield and associated return on investment.

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