Modelling climate change impacts on wet and dry season rice in Cambodia

Irregular rainfall, rising temperatures and changing frequency and intensity of extreme weather events are projected to reduce crop yields and threaten food security across the tropical monsoon sub-region. However, the anticipated extent of impact on crop yields and crop water productivity (CWP) is not yet thoroughly understood. The impacts of climate change on rice yields and CWP are assessed over the Northern Tonle Sap Basin in Cambodia by applying the AquaCrop model into the mid- (2041–2070) to long-future (2071–2099) under two Representative Concentration Pathways (RCPs) (4.5 and 8.5). Short (95 days), medium (125 days) and long (155 days) cycle varieties are tested during the wet and dry seasons. An assessment of different sowing dates and irrigation strategies (fixed and net irrigation during the dry season) elucidated the variation in response to changing environmental conditions. Higher yields (+15% by 2041–2070 and +30% by 2071–2099) and CWP values (+42% by 2071–2099) are expected if using short-cycle varieties, in particular when sown in July. Dry season rice yields are also projected to increase (+28% by 2071–2099), especially under a higher greenhouse gas emission scenario (RCP 8.5) compared to a medium emission scenario (RCP 4.5) as a result of the CO2 fertilization effect. Depending on the climatic scenario, rice variety, irrigation scheme, and sowing date, increasing heat and drought-stress conditions are likely to have different impacts on rice yields and CWP over time. Overall, this study highlights the benefits of adjusting crop calendars to identify the most suitable irrigation schedules and rice varieties to effectively adapt to projected future climate

Climate trends and extremes in the Indus River Basin, Pakistan: implications for agricultural production

ABSTRACT: Historical and future projected changes in climatic patterns over the largest irrigated basin in the world, the Indus River Basin (IRB), threaten agricultural production and food security in Pakistan, in particular for vulnerable farming communities. To build a more detailed understanding of the impacts of climate change on agricultures in the IRB, the present study analyzes (1) observed trends in average temperature, precipitation and related extreme indicators, as well as seasonal shifts over a recent historical period (1997-2016); and (2) statistically downscaled future projections (up to 2100) from a set of climate models in conjunction with crop-specific information for the four main crops of the IRB: wheat, cotton, rice and sugarcane. Key findings show an increasing trend of about over 0.1ºC/year in observed minimum temperature across the study area over the historical period, but no significant trend in maximum temperature. Historical precipitation shows a positive annual increase driven mainly by changes in August and September. Future projections highlight continued warming resulting in critical heat thresholds for the four crops analyzed being increasingly exceeded into the future, in particular in the Kharif season. Concurrently, inter-annual rainfall variability is projected to increase up to 10-20% by the end of the 21st century, augmenting uncertainty of water availability in the basin. These findings provide insight into the nature of recent climatic shifts in the IRB and emphasize the importance of using climate impact assessments to develop targeted investments and efficient adaptation measures to ensure resilience of agriculture in Pakistan into the futur

Greenhouse Gas Emissions and Yield Production from an Organic and Conventional Fertilization on Quinoa

The high nutritional properties of quinoa have resulted in a production increase worldwide. The resistance to environmental stresses renders this crop suitable for sustainable farming systems. Few studies have examined the impact of different agricultural management strategies and its contribution to climate change. In this work, we quantify soil greenhouse gas (GHG) emissions, in terms of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), and crop productivity (yields and biomass) under conventional (urea) and organic (digestate) fertilization. Significant differences (p 2O cumulative emissions are reported between digestate (50–100 kg N ha−1), urea (50–100 kg N ha−1) and the control (0 kg N ha−1). Higher cumulative GHG emissions are observed under 100 kg N ha−1 of digestate (337.8 kg C ha−1 CO2 and 0.23 kg N ha−1 for N2O) compared to treatments with lower nitrogen (N) inputs. However, yield and biomass production do not show significant differences (p > 0.05) with increasing nutrient application. Hence, this study opens the discussion about the pros and cons of increasing fertilization to improve yields besides providing agricultural extension workers with additional information to promote sustainable quinoa production worldwide

Farmers’ Perceptions of Climate Change and Agricultural Adaptation in Burkina Faso

The Sahel region is considered a hotspot for climate change hazards and vulnerability of weather reliant sectors, including agriculture. Farmers in Burkina Faso have a long history of adapting their farming activities to frequent changes in climate. Using 150 in-person surveys, this study assesses farmers’ perceptions of climate change based on multiple climate variables, and reviews adaptation practices, including soil and water conservation strategies, in the Soudanian, Soudano-Sahelian, and Sahelian agroclimatic zones of Burkina Faso. In general, farmers are aware of changing climatic conditions, including increased temperatures, greater rainfall variability, heavier precipitation events, delayed onset, and premature offset of the rainy season. However, farmers perceive shifts in climate differently depending on their location and agroclimatic zone. As a result, different adaption strategies are implemented by farmers according to the climatic, societal, and economic context. Survey results show that in the Sahel, climate adaptation strategies rely on traditional knowledge and experimental approaches; whereas in the Soudanian zone, where weather conditions are more favorable for agriculture, adaptation practices are market oriented. These regional differences are important for targeting advisory services, planning processes, and decision-making to support the effective provision of weather and climate information services to the last mile

Climate change impacts on irrigated crops in Cambodia

Increasing heat-stress conditions, rising evaporative demand and shifting rainfall patterns may have multifaceted impacts on Cambodia's agricultural systems, including vegetable production. Concurrently, domestic vegetable supply is highly seasonal and inadequate to meet the domestic food demand, which consequently poses risks to food security locally, particularly in rural areas. This study assesses the impact of climate change on the yields and crop water productivity (CWP) of tomato, pak choi and yard-long bean cultivated year-round under different irrigated conditions (drip, furrow and net irrigation) in Siem Reap, Cambodia. The findings of this study show a similar annual precipitation decline (-23%) when comparing the 2017-2040 and 2070-2099 periods for both Representative Concentration Pathways (RCPs 4.5 and 8.5), though with significant seasonal differences between the two climate scenarios. Increasing water and heat-stress conditions are expected to have adverse impacts on tomato plants compared to pak choi and yard-long bean, which have a much higher heat tolerance. Differing yield trends are expected depending on the transplanting/sowing date, irrigation method and RCP. In tomato, for example, a -55% yield loss is projected by the end-century (2070-2099) when transplanting in January, whereas a + 37% yield increase is expected between November and December over the same period. In addition, pak choi yield enhancements of up to +30% are projected if sowing in May under RCP 8.5 for both drip and net irrigation conditions. Similarly, higher yard-long bean yields are simulated under RCP 8.5 (+29%) compared to RCP 4.5 (+11%) for the average of all sowing dates (January to December) and irrigation methods (drip, furrow and net irrigation). In sum, the findings of this work are relevant for evidence-based decision-making and the development of projects, policies and programmes increasingly informed by simulation results from bundling climate-crop approaches to transform agriculture in response to climate change

Composition and distribution of medically important phlebotomines (Diptera: Psychodidae) in the municipalities of Tierralta and Valencia (Córdoba, Colombia)

Background & objectives: Ecoepidemiological studies of cutaneous leishmaniasis and regular monitoring of Lutzomyia species have generated a knowledge base that can be used for control and prevention strategies targeted at the disease transmission dynamics in focal areas of Colombia. In this study, the presence and spatial distribution of phlebotomines of medical importance in the municipalities of Tierralta (El Loro and Tuis Tuis villages) and Valencia (Guadua and Mieles villages) were determined. Methods: Entomological surveys were performed in 2015 (months of June, September and November) and samples were collected via CDC-traps located in intradomicilary and peridomiciliary areas in the municipalities of Tierralta and Valencia (Department of Córdoba, Colombia). Active searches were also carried out with a mouth aspirator to collect adult phlebotomines from resting sites. ANOVA and Kruskal-Wallis tests were performed to assess if the differences between the communities of phlebotomines. Spatial distribution maps of the Lutzomyia species were generated. Results: A high species diversity of Lutzomyia was observed with a total of 1677 Lutzomyia individuals belonging to 12 species. Among these species, Lu. panamensis was the most abundant (80.18%). The composition of the intradomicilary and peridomiciliary phlebotomines varied significantly (F = 0.9962; df = 1; p = 0.02895). Species like Lu. carpenteri, Lu. camposi, Lu. dysponeta, Lu. atroclavata and Lu. yuilli yuilli were recorded for the first time in the Department of Córdoba, Colombia. Interpretation & conclusion: The spatial distribution shows that Lu. panamensis and Lu. gomezi are predominant and present in areas with high concentration of houses. This study provides basic information on new records of phlebotomines in the Department of Córdoba. The results suggest that greater vector-human contact occurs in the peridomiciliary environment and that a high number of Lutzomyia species associated with the transmission of leishmaniasis are present in Colombia