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"Knox, J. W. (Jerry W.)"
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Modelling water fluxes to improve banana irrigation scheduling and management in Magdalena, Colombia
In this paper, an irrigation scheduling model for banana (Musa sp.) was developed to simulate crop growth and water fluxes under typical commercial plantation conditions. Whilst generic models exist for scheduling irrigation for many crops, their suitability for bananas are limited because of the asynchronous nature of crop growth. Individual fields on banana plantations typically contain trees at varying stages in their development cycle, so it is important for scheduling to account for this heterogeneity in simulating crop production. A crop modelling approach was developed using field data from Magdalena, an economically important region of banana production in Colombia. Following model development and calibration, irrigation water demand was estimated and weekly irrigation scheduling advice then transmitted by SMS to individual farmers in the region. The model also takes into account farmer feedback on actual irrigation practices to compare against estimated irrigation demands and to train model performance. Despite good model calibration, analysis of irrigation practices from farmer feedback showed only moderate to poor correlation between actual irrigation applications and the scheduling guidance. This implies a reluctance of farmers to change long-established traditional irrigation management practices, despite awareness of the impacts of systematic over-irrigation on yields and increased nutrient leaching risks. Significant ongoing research efforts will be needed to support improved knowledge and practical water management for key plantation crops.
Journal Article
Barriers to mutational testing in patients with gastrointestinal stromal tumors (GIST) – a survey of life raft group members
Background
Due to the low mutational testing rate in patients with Gastrointestinal Stromal Tumors (GIST), The Life Raft Group (LRG), a non-profit organization that provides support, advocacy and conducts research for patients with GIST, analyzed various factors that may have an impact on patients’ ability to receive mutational testing.
Methods
A survey about mutational testing for patients with GIST or their caregivers, was conducted in June 2020. The survey, sent to 1004 GIST patients and caregivers through email, was promoted through social media with instructions to contact the LRG to participate. The survey was designed by the LRG Patient Registry Department. Members of the LRG, regardless of Patient Registry status, were eligible to participate.
Results
A total of 295 patients/caregivers participated in this study (response rate: 29.4%). The percentage of patients who indicated they had received mutational testing was much higher in this survey (80%) than in the general GIST community (26.7%).
Several reasons were cited for having a test, including: “My doctor ordered/suggested that I have it done” (54%); “The Life Raft Group advised/suggested I have it done” (25%); “I asked my doctor to have it done” (22%); “I had it done as part of a clinical trial” (5%); “I am not sure” (3%) and “Other” (14%). Mutational testing resulted in a treatment change in 25% of cases. Patients were able to select more than one option when completing this question resulting in a percentage greater than 100.
Conclusions
The LRG membership is voluntary and proactive; patients who join are more likely to participate in surveys and mutational testing, as well as more likely to have a GIST specialist. Mutational testing can influence understanding of a patient’s GIST and the treatment best suited to each case. These are extremely important findings, as it helps ensure that patients are on the proper treatment, which should lead to better outcomes.
Journal Article
Water and energy footprint of irrigated agriculture in the Mediterranean region
Irrigated agriculture constitutes the largest consumer of freshwater in the Mediterranean region and provides a major source of income and employment for rural livelihoods. However, increasing droughts and water scarcity have highlighted concerns regarding the environmental sustainability of agriculture in the region. An integrated assessment combining a gridded water balance model with a geodatabase and GIS has been developed and used to assess the water demand and energy footprint of irrigated production in the region. Modelled outputs were linked with crop yield and water resources data to estimate water (m3 kg−1) and energy (CO2 kg−1) productivity and identify vulnerable areas or 'hotspots'. For a selected key crops in the region, irrigation accounts for 61 km3 yr−1 of water abstraction and 1.78 Gt CO2 emissions yr−1, with most emissions from sunflower (73 kg CO2/t) and cotton (60 kg CO2/t) production. Wheat is a major strategic crop in the region and was estimated to have a water productivity of 1000 t Mm−3 and emissions of 31 kg CO2/t. Irrigation modernization would save around 8 km3 of water but would correspondingly increase CO2 emissions by around +135%. Shifting from rain-fed to irrigated production would increase irrigation demand to 166 km3 yr−1 (+137%) whilst CO2 emissions would rise by +270%. The study has major policy implications for understanding the water–energy–food nexus in the region and the trade-offs between strategies to save water, reduce CO2 emissions and/or intensify food production.
Journal Article
A multi-level framework for adaptation to drought within temperate agriculture
Droughts affect a range of economically important sectors but their impacts are usually most evident within agriculture. Agricultural impacts are not confined to arid and semi-arid regions, but are increasingly experienced in more temperate and humid regions. A transferable drought management framework is needed to transition from coping to adapting to drought through supporting improved planning and policy decision-making through the supply chain from primary producers to consumers. A combination methodology using a Driver-Pressure-State-Impact-Response (DPSIR) approach, an analysis of weekly agricultural trade publications and semi-structured interviews were used to explore drought impacts and responses, using the 2018 UK drought as a case study. Whilst most reported responses were on-farm, a diverse range of measures were implemented across institutional scales and through the supply chain, reflecting complex interactions within the food system. However, drought responses were dominated by reactive and crisis-driven actions to cope with, or enhance the recovery from, drought; but which contributed little to increased resilience to future droughts. Our transferable drought management framework shows how improved collaboration and multi-sector engagement across spatial, governance and supply-chain scales to develop human and social capital can enable the transition from coping (short-term and reactive) to adapting (long-term and anticipatory) strategies to increase agricultural resilience to future droughts
Journal Article
Advances in Irrigation Agronomy
Irrigation has been used for thousands of years to maximize the performance, efficiency and profitability of crops and it is a science that is constantly evolving. This potential for improved crop yields has never been more important as population levels and demand for food continue to grow. Recognising the need for a coherent and accessible review of international irrigation research, this book examines the factors influencing water productivity in individual crops. It focuses on nine key plantation/industrial crops on which millions of people in the tropics and subtropics depend for their livelihoods (banana, cocoa, coconut, coffee, oil palm, rubber, sisal, sugar cane and tea). Linking crop physiology, agronomy and irrigation practices, this is a valuable resource for planners, irrigation engineers, agronomists and producers concerned with the international need to improve water productivity in agriculture in the face of increased pressure on water resources.
eBook
Identifying trade-offs and reconciling competing demands for water - integrating agriculture into a robust decision-making framework
Increasing demands for water, driven by population growth and socio‐economic development, environmental regulations and future climate uncertainty, are highlighting limitations on water supplies. This water‐energy‐food‐environment nexus is not confined to semi‐arid regions but is emerging as a key business, societal and economic risk in humid and temperate countries, where abundant water supplies and regulation have historically coped with fluctuating demands between industry, power generation, agriculture, domestic supply and the environment. In the UK, irrigation is supplemental to rainfall, consumptive in use and concentrated in the driest years and most resource‐stressed catchments. This paper describes an empirical application of a mixed methods approach to integrate agriculture into a robust decision‐making framework, focusing on a water‐stressed region in England. The approach shows that competing demands between sectors can be reconciled and that potential options or portfolios compatible with multi‐sectoral collaboration and investment can be identified. By combining model outputs to forecast the impacts of climate and socio‐economic change on agricultural demand within a regional water resource simulator, future spatial estimates of demand were derived. A set of search and tracked metrics were used to drive multi‐criteria searches to identify preferred supply and demand management orientated portfolios. The methodological challenges in forecasting agricultural demand, defining acceptable ‘trade‐offs’, managing scale and uncertainty issues and the importance of engendering open dialogue between stakeholders is described. The study provides valuable insights for countries where similar emergent issues regarding conflicts over water demand exist.
Journal Article
WATER RELATIONS AND IRRIGATION REQUIREMENTS OF ONION (ALLIUM CEPA L.): A REVIEW OF YIELD AND QUALITY IMPACTS
The results of international research on the water relations and irrigation needs of onions have been synthesised in an attempt to link fundamental studies on crop physiology to irrigation practices, and consequent impacts on crop yield, quality and storage. Following a brief introduction on its origins and centres of production, a synthesis of research on crop development including plant water relations, crop water requirements, yield response to water, irrigation systems and scheduling are presented. Most of the evidence stems from research conducted in arid and semi-arid regions, notably the USA, India, Spain and Turkey. The findings confirm that onion seasonal water requirements are highly variable depending on agroclimate, location and season, as are the crop coefficients (Kc) which range from 0.4 to 0.7 (initial stage), 0.85 to 1.05 (middle development) and 0.6 to 0.75 (final stage). Seasonal irrigation needs are reported to vary from 225 to 1040 mm to produce between 10 and 77 t ha−1. The most sensitive stages for water stress are at emergence, transplanting and bulb formation. Final crop quality can also be affected by water excess. Water stress at specific stages can negatively impact on quality leading to reduced size and multi-centred bulbs. In recent years, pressure on water resources, retailer demands for quality assurance and rising production costs have meant that onion irrigation has switched from traditional low efficiency (furrow) methods to more efficient advanced (sprinkler and drip) technologies. For scheduling, optimal soil water potential thresholds for triggering irrigation were found to be between −17 and −27 kPa for drip and furrow irrigation. Research is underway to maximise water use efficiency in onions, but the deficit irrigation regimes being tested under experimental conditions have yet to be adopted commercially.
Journal Article
Simulating impacts of irrigation heterogeneity on onion (Allium cepa L.) yield in a humid climate
This paper reports on a study combining experimental field data with biophysical crop modelling to assess the impacts of irrigation heterogeneity on onion yield. The AquaCrop model was calibrated and validated for brown onion (cv Arthur) and used to simulate yield variability under a set of contrasting soil and agroclimatic conditions assuming perfect (100% uniform) irrigation. The impacts of non-uniform irrigation as measured on-farm under two overhead systems (mobile hose reel fitted with boom and a linear move) were then evaluated using scenario analysis and multi-model runs. Stochastic modelling confirmed that the lowest yield (8.6 t DM/ha) occurs on the lowest moisture retentive soils under the driest agroclimatic conditions with non-uniform irrigation. There is much greater yield variability in dry years compared to wet years. In wet years, rainfall reduces the scheduled number of irrigation events and buffers the effects of irrigation non-uniformity on yield. Yields were more variable under the mobile hose reel system fitted with the boom compared to the fixed linear move system. The modelled yield variability under non-uniform was similar to the observed yields reported by growers based on an industry survey. The study highlights the importance of achieving high irrigation uniformity in dry years on light soils to maximise yield and provides useful data for evaluating the potential yield benefits that might accrue from precision irrigation.
Journal Article
