127 research outputs found
The impacts of increased heat stress events on wheat yield under climate change in China
China is the largest wheat producing country in the world. Wheat is one of the two major staple cereals consumed in the country and about 60% of Chinese population eats the grain daily. To safeguard the production of this important crop, about 85% of wheat areas in the country are under irrigation or high rainfall conditions. However, wheat production in the future will be challenged by the increasing occurrence and magnitude of adverse and extreme weather events. In this paper, we present an analysis that combines outputs from a wide range of General Circulation Models (GCMs) with observational data to produce more detailed projections of local climate suitable for assessing the impact of increasing heat stress events on wheat yield. We run the assessment at 36 representative sites in China using the crop growth model CSM-CropSim Wheat of DSSAT 4.5. The simulations based on historical data show that this model is suitable for quantifying yield damages caused by heat stress. In comparison with the observations of baseline 1996-2005, our simulations for the future indicate that by 2100, the projected increases in heat stress would lead to an ensemble-mean yield reduction of –7.1% (with a probability of 80%) and –17.5% (with a probability of 96%) for winter wheat and spring wheat, respectively, under the irrigated condition. Although such losses can be fully compensated by CO2 fertilization effect as parameterized in DSSAT 4.5, a great caution is needed in interpreting this fertilization effect because existing crop dynamic models are unable to incorporate the effect of CO2 acclimation (the growth enhancing effect decreases over time) and other offsetting forces
A multi-data assessment of land use and land cover emissions from Brazil during 2000–2019
This is the final version. Available on open access from IOP Publishing via the DOI in this recordData availability statement:
The data that support the findings of this study are available upon reasonable request from the authors.Brazil is currently the largest contributor of land use and land cover change (LULCC) carbon dioxide net emissions worldwide, representing 17%-29% of the global total. There is, however, a lack of agreement among different methodologies on the magnitude and trends in LULCC emissions and their geographic distribution. Here we perform an evaluation of LULCC datasets for Brazil, including those used in the annual global carbon budget (GCB), and national Brazilian assessments over the period 2000-2018. Results show that the latest global HYDE 3.3 LULCC dataset, based on new FAO inventory estimates and multi-annual ESA CCI satellite-based land cover maps, can represent the observed spatial variation in LULCC over the last decades, representing an improvement on the HYDE 3.2 data previously used in GCB. However, the magnitude of LULCC assessed with HYDE 3.3 is lower than estimates based on MapBiomas. We use HYDE 3.3 and MapBiomas as input to a global bookkeeping model (bookkeeping of land use emission, BLUE) and a process-based Dynamic Global Vegetation Model (JULES-ES) to determine Brazil's LULCC emissions over the period 2000-2019. Results show mean annual LULCC emissions of 0.1-0.4 PgC yr-1, compared with 0.1-0.24 PgC yr-1 reported by the Greenhouse Gas Emissions Estimation System of land use changes and forest sector (SEEG/LULUCF) and by FAO in its latest assessment of deforestation emissions in Brazil. Both JULES-ES and BLUE now simulate a slowdown in emissions after 2004 (-0.006 and -0.004 PgC yr-2 with HYDE 3.3, -0.014 and -0.016 PgC yr-2 with MapBiomas, respectively), in agreement with the Brazilian INPE-EM, global Houghton and Nassikas book-keeping models, FAO and as reported in the 4th national greenhouse gas inventories. The inclusion of Earth observation data has improved spatial representation of LULCC in HYDE and thus model capability to simulate Brazil's LULCC emissions. This will likely contribute to reduce uncertainty in global LULCC emissions, and thus better constrains GCB assessments
Impacts of extreme weather on wheat and maize in France: evaluating regional crop simulations against observed data
Extreme weather conditions can strongly affect agricultural production, with negative impacts that can at times be detected at regional scales. In France, crop yields were greatly influenced by drought and heat stress in 2003 and by extremely wet conditions in 2007. Reported regional maize and wheat yields where historically low in 2003; in 2007 wheat yields were lower and maize yields higher than long-term averages. An analysis with a spatial version (10x10 km) of th EPIC crop model was tested with regards to regional crop yield anomalies of wheat and maize resulting from extreme weather events in France in 2003 and 2007, by comparing simulated results against reported regional crops statistics, as well as using remotely sensed soil moisture data. Causal relations between soil moisture and crop yields were specifically analyzed. Remotely sensed (AMSR-E) JJA soil moisture correlated significantly with reported regional crop yield for 2002-2007. The spatial correlation between JJA soil moisture and wheat yield anomalies was positive in dry 2003 and negative in wet 2007. Biweekly soil moisture data correlated positively with wheat yield anomalies from the first half of June until the second half of July in 2003. In 2007, the relation was negative the first half of June until the second half of August. EPIC reproduced observed soil dynamics well, and it reproduced the negative wheat and maize yield anomalies of the 2003 heat wave and drought, as well as the positive maize yield anomalies in wet 2007. However, it did not reproduce the negative wheat yield anomalies due to excessive rains and wetness in 2007. Results indicated that EPIC, in line with other crop models widely used at regional level in climate change studies, is capable of capturing the negative impacts of droughts on crop yields, while it fails to reproduce negative impacts of heavy rain and excessively wet conditions on wheat yield, due to poor representations of critical factors affecting plant growth and management. Given that extreme weather events are expected to increase in frequency and perhaps severity in coming decades, improved model representation of crop damage due to extreme events is warranted in order to better quantify future climate change impacts and inform appropriate adaptation responses
The environmental impact of fertilizer embodied in a wheat-to-bread supply chain
Food production and consumption cause approximately one-third of total greenhouse gas emissions, and therefore delivering food security challenges not only the capacity of our
agricultural system, but also its environmental sustainability. Knowing where and at what level environmental impacts
occur within particular food supply chains is necessary if
farmers, agri-food industries and consumers are to share
responsibility to mitigate these impacts. Here we present
an analysis of a complete supply chain for a staple of the
global diet, a loaf of bread. We obtained primary data for all
the processes involved in the farming, production and transport
systems that lead to the manufacture of a particular brand of
800 g loaf. The data were analysed using an advanced life
cycle assessment (LCA) tool, yielding metrics of environmental
impact, including greenhouse gas emissions. We show
that more than half of the environmental impact of producing
the loaf of bread arises directly from wheat cultivation, with
the use of ammonium nitrate fertilizer alone accounting for
around 40%. These findings reveal the dependency of bread
production on the unsustainable use of fertilizer and illustrate
the detail needed if the actors in the supply chain are to
assume shared responsibility for achieving sustainable
food production
Can barley (Hordeum vulgare L. s.l.) adapt to fast climate changes? A controlled selection experiment
An operational approach to high resolution agro-ecological zoning in West-Africa
Research ArticleThe objective of this work is to develop a simple methodology for high resolution crop suitability
analysis under current and future climate, easily applicable and useful in Least
Developed Countries. The approach addresses both regional planning in the context of
climate change projections and pre-emptive short-term rural extension interventions
based on same-year agricultural season forecasts, while implemented with off-the-shelf
resources. The developed tools are applied operationally in a case-study developed in
three regions of Guinea-Bissau and the obtained results, as well as the advantages
and limitations of methods applied, are discussed. In this paper we show how a simple
approach can easily generate information on climate vulnerability and how it can be operationally
used in rural extension servicesinfo:eu-repo/semantics/publishedVersio
Fertilization Strategies Based on Climate Information to Enhance Food Security Through Improved Dryland Cereals Production
Rainfall uncertainty and nutrient deficiency affect sorghum production in Sahel. This study aimed at (i) determining the responses (varieties*water*nitrogen) of various West-African sorghum (Sorghum bicolor L. Moench) varieties to the application of fertilizer (NPK and urea) at selected growing stages according to water regime (irrigated or not, different rainfall patterns) and (ii) simulating them to define alternative fertilization strategies. This chapter proposes alternative fertilization strategies in line with rainfall patterns. Split plot experiments with four replications were carried out in two locations (Senegal), with four improved sorghum varieties (Fadda, IS15401, Soumba and 621B). Treatments were T1, no fertilizer; T2 = 150 kg/ha of NPK (15-15-15) at emergence +50 kg/ha of urea (46%) at tillering +50 Kg/ha of urea at stem extension; T3 = half rate of T2 applied at the same stages; T4 = 150 kg/ha of NPK + 50 kg/ha of urea at stem extension +50 kg/ha of urea at heading, and T5 = half rate of T4 applied at the same stages. Plant height, leaf number, grain yield, and biomass were significantly affected by the timing and rate of fertilizers. Grain yield were affected by water*nitrogen and nitrogen*variety interactions. It varied from 2111 to 261 kg/ha at “Nioro du Rip” and from 1670 to 267 kg/ha at “Sinthiou Malème”. CERES-Sorghum model overestimated late fertilizer grain yields. To achieve acceptable grain yield, fertilizers application should be managed regarding weather
The Quadruple Squeeze: Defining the safe operating space for freshwater use to achieve a triply green revolution in the Anthropocene
Humanity has entered a new phase of sustainability challenges, the Anthropocene, in which human development has reached a scale where it affects vital planetary processes. Under the pressure from a quadruple squeeze—from population and development pressures, the anthropogenic climate crisis, the anthropogenic ecosystem crisis, and the risk of deleterious tipping points in the Earth system—the degrees of freedom for sustainable human exploitation of planet Earth are severely restrained. It is in this reality that a new green revolution in world food production needs to occur, to attain food security and human development over the coming decades. Global freshwater resources are, and will increasingly be, a fundamental limiting factor in feeding the world. Current water vulnerabilities in the regions in most need of large agricultural productivity improvements are projected to increase under the pressure from global environmental change. The sustainability challenge for world agriculture has to be set within the new global sustainability context. We present new proposed sustainability criteria for world agriculture, where world food production systems are transformed in order to allow humanity to stay within the safe operating space of planetary boundaries. In order to secure global resilience and thereby raise the chances of planet Earth to remain in the current desired state, conducive for human development on the long-term, these planetary boundaries need to be respected. This calls for a triply green revolution, which not only more than doubles food production in many regions of the world, but which also is environmentally sustainable, and invests in the untapped opportunities to use green water in rainfed agriculture as a key source of future productivity enhancement. To achieve such a global transformation of agriculture, there is a need for more innovative options for water interventions at the landscape scale, accounting for both green and blue water, as well as a new focus on cross-scale interactions, feed-backs and risks for unwanted regime shifts in the agro-ecological landscape
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