Feasibility of a low-cost weather sensor network for agricultural purposes : a preliminary assessment

This study has focused on challenges encountered when setting up a weather-network for agricultural purposes (e.g. linking temperature to the suitability of crops and pest incidence) with only low-cost sensors and materials. The study included a set of experiments in a meteorological station and a one-month period of observations in a large coffee plantation with a complex terrain in Costa Rica. The created network is intended to be linked to agronomic trials, and are part of a package that will make farmers the scientists in a range of extension projects. Ongoing projects provide farmers with a range of seeds that are tested, while feedback is provided by a crowd-sourcing approach. Farmers send text messages back to the project managers. The coordinates of the farmers' field can be extracted from a stack of rasters with climate information, resulting in a clear understanding of the conditions during the agronomic trials. Experiments with different sensor (iButton DS1923) resolution showed that losses in precision when using a low temperature resolution are small compared to other losses (e.g. interpolation in time and space). Using a high-resolution for humidity observations provides very small improvements over low-resolution, as it provides data with the same accuracy. Experiments also focused on adjustment to PVC tubes, which functioned as sensor-shielding. All adjustments provided large differences with a certified shielding for the maximum temperature on sunny days. The best coating to limit the impact of radiation was insulating foil, and it is recommended that future experiments focus more on aeration, as this has not yet provided the expected benefits. As no (combination of) adjustments provided data in line with the reference station, different types of data calibration were tested. While direct correction of data by a polynomial regression model provided reasonable results, the main difference between PVC shields and the certified sensor was caused by the faster heating/cooling over time (thermal-inertia properties). By creating a linear model between change in time in the PVC and certified shield, a calibration model was developed that has been used to correct data. This has been done by setting an anchor point on each day, to which the corrected change was added/subtracted. With some minor additional calibration, this model provided data that was very similar to data in the certified shield. After the initial experiments were analysed, one hundred sensors were placed in a large coffee plantation with a 500 meter elevation gradient; fourteen sensors were lost and six provided incorrect data. The correlation between temperature and a range of variables was assessed. This included static (elevation, slope, aspect, canopy height, leaf-area-index and daily radiation) and dynamic (hourly radiation) covariates. On average, 52% of variance in temperature could be explained by static covariates. Including hourly radiation as covariate instead of daily radiation improved this model by 1%. Elevation is by far the most important independent variable (± 67%), although this influence is lower during periods with high temperature. A higher daily maximum temperature reduces the strength of elevation/temperature correlation. These are periods during which temperature is harder to predict based on interpolation in the complex terrain. A lower correlation between elevation and temperature can partly be compensated by a stronger correlation with other covariates; hourly radiation contributes on average 20% to the temperature-predicting models during hours with sun (although the models can only predict 54% of variance during these hours). Geostatistical interpolation has been tested for 80, 40, 20 and 8 sensors, with different kriging approaches and sets of covariates. Cross-validation provided the best results for universal kriging with elevation. Dynamic kriging provided smaller errors only with the full 80-sensor network. Co- and Spatio-Temporal kriging provided larger errors in predicting a left-out sensor, while data of the sensors included in the kriging showed least modification. The preferred approach depends on the network objective and reliability of data. While the network in this study cost ±US$8,700, a sufficiently accurate network of 25 sensors, can be created with a smaller budget: 20 low-res (temperature) iButton sensors (DS1922L-F5), 5 high-res (temperature and humidity) iButton sensors (DS1923-F5), 50m thin white PVC, 50 PVC elbows, 1m2 insulating foil, a small amount of fibre-glass mesh, and labor for construction (drilling holes and assembling). The cost for this weather network - which can store 341 days of 1-hour resolution data - will be approximately US$ 1,450. A 50-sensor network would still cost 500m) in the area. The other factors that were included showed smaller links to temperature, although at certain moments this could become more important. This link of temperature with different factors that can be created from existing maps and algorithms can be used to reduce the number of sensors that would be required in a certain network. However, hours during which it was warm and sunny showed very little linkages to the commonly available factors (variables). Including hourly sunshine could partly compensate this, by having a relatively strong link to temperature, but this is still smaller than during nighttime/cloudy periods. The percentage of variation in temperature that can be explained at different hours (dotted line) and the relative contribution of the studied factors is shown in the figure below. Based on this knowledge, different approaches of data interpolation (creating a network from point-based observations) have been tested, while reducing the number of sensors to 40, 20 and 8. The most useful results were found for an approach that only included elevation, as this is the most stable variable. More advanced (geo-statistical) approached require a larger number of sensors (> 50), which places them outside the objective of these networks: to be available at low costs. The first set of experiments, aiming to create a shield that would perform similar to a WMO certified shield, did not provide very good results. The influence of radiation could not be avoided by improving air flow (drilling holes) and adding different types of foil and tape. While correction would thus still be required, the selected correction approach did perform very well at different locations. It would still be important to better study the actual shield, by experimenting by even more combinations of materials. The data that was derived from the network in a large coffee plantation in Costa Rica, showed that variation in temperature is especially linked to differences in elevation. Factors such as density and height of the canopy played a smaller role. During hours with sun, elevation could explain less of the variation, but the hourly differences in sun/shadow could partly compensate this. The different factors can be used to create a relatively accurate networks with around 25 sensors, which would cost less than US$ 1,500 and can measure every hour for a period of around one year. This would be ideal for most annual crops

Estimating costs of nature management in the European Union : Exploration modelling for PBL’s Nature Outlook

A cost model was developed for the Nature Outlook of PBL Netherlands Environmental Assessment Agency.This cost model estimates one-off and recurrent costs of natural vegetation based on Corine land cover typesthroughout Europe. Cost estimates were made for the base year 2000 and future scenarios, including aTrend scenario based on current EU policies and normative perspectives, including Strengthening CulturalIdentity (SCI), Allowing Nature to Find its Way (NFW), Going with the Economic Flow (GEF) and Workingwith Nature (WWN). These scenarios all have a time horizon of 2050. To estimate various costs acomprehensive data analysis was carried out and a cost model was developed based on the IKN model forDutch Nature Policy. The model estimates costs of recurrent management in the base year on € 5.6 billionper year in the EU-28. Costs of recurrent management within the Natura 2000 network is estimated on € 3.5billion per year. Recurrent management costs in 2050 in the Trend scenario were estimated on € 5.2 billionper year. One-off costs of land purchase are estimated at € 450 per hectare per year and construction costs€ 1028 per hectare per year. One-off costs of the perspectives are 5.09 (SCI), 6.56 (NFW), 6.20 (GEF) and9.79 billion euro per year (WWN

Veilig stijgen en landen op Schiphol : actualisatie vergoedingsregeling graanteelt om ganzen te weren

In het Convenant reduceren risico vogelaanvaringen Schiphol 2016-2018 van maart 2016 is door een groot aantal partijen afspraken gemaakt om het aantal vogelaanvaringen met vliegtuigen rond Schiphol te verminderen. Het convenant is getekend door de Vereniging van Nederlandse Verkeersvliegers (VNV), Schiphol, Vereniging Natuurmonumenten, Staatsbosbeheer, Landschap Noord-Holland, Land- en Tuinbouworganisatie (LTO) Nederland, B&W Gemeente Haarlemmermeer, Gedeputeerde Staten van Noord-Holland, Zuid-Holland en Utrecht, en de Nederlandse Staat (vertegenwoordigd door de staatssecretaris van Infrastructuur en Milieu). In het convenant staan een aantal voornemens en maatregelen. Eén van de maatregelen is het zo veel mogelijk beperken van het foerageren van ganzen en andere vogels in de zomerperiode in de buurt van start- en landingsbanen. Het versneld onderwerken van graanresten kan hieraan een bijdrage leveren. Ganzen en andere vogels komen in de zomer na de graanoogst graankorrels zoeken en opeten. De afgelopen jaren is er een (vrijwillige) vergoedingsregeling geweest; hierbij zijn voor ruim 2.000 ha contracten afgesloten. De contracten lopen tot en met 2017. Voor de jaren na 2018 hebben de convenantpartijen gevraagd om opnieuw te kijken naar de opbouw van de verschillende posten voor het voorstel voor de basisvergoeding. Het ministerie van Infrastructuur en Milieu (I&M), afdeling Luchtvaartveiligheid, heeft deze adviesaanvraag bij het Wageningen Economic Research (voorheen LEI Wageningen UR) ingediend. Ook is gevraagd naar de ontwikkeling van het areaal granen in de afgelopen jaren in het gebied in vergelijking met het hele land en de ons omringende landen

FIRST EXPERIENCES WITH A NOVEL FARMER CITIZEN SCIENCE APPROACH: CROWDSOURCING PARTICIPATORY VARIETY SELECTION THROUGH ON-FARM TRIADIC COMPARISONS OF TECHNOLOGIES (TRICOT)

SUMMARYRapid climatic and socio-economic changes challenge current agricultural R&D capacity. The necessary quantum leap in knowledge generation should build on the innovation capacity of farmers themselves. A novel citizen science methodology, triadic comparisons of technologies or tricot, was implemented in pilot studies in India, East Africa, and Central America. The methodology involves distributing a pool of agricultural technologies in different combinations of three to individual farmers who observe these technologies under farm conditions and compare their performance. Since the combinations of three technologies overlap, statistical methods can piece together the overall performance ranking of the complete pool of technologies. The tricot approach affords wide scaling, as the distribution of trial packages and instruction sessions is relatively easy to execute, farmers do not need to be organized in collaborative groups, and feedback is easy to collect, even by phone. The tricot approach provides interpretable, meaningful results and was widely accepted by farmers. The methodology underwent improvement in data input formats. A number of methodological issues remain: integrating environmental analysis, capturing gender-specific differences, stimulating farmers' motivation, and supporting implementation with an integrated digital platform. Future studies should apply the tricot approach to a wider range of technologies, quantify its potential contribution to climate adaptation, and embed the approach in appropriate institutions and business models, empowering participants and democratizing science

Volume–outcome relationship of liver surgery: a nationwide analysis

Background: Evidence for an association between hospital volume and outcomes for liver surgery is abundant. The current Dutch guideline requires a minimum volume of 20 annual procedures per centre. The aim of this study was to investigate the association between hospital volume and postoperative outcomes using data from the nationwide Dutch Hepato Biliary Audit. Methods: This was a nationwide study in the Netherlands. All liver resections reported in the Dutch Hepato Biliary Audit between 2014 and 2017 were included. Annual centre volume was calculated and classified in categories of 20 procedures per year. Main outcomes were major morbidity (Clavien–Dindo grade IIIA or higher) and 30-day or in-hospital mortality. Results: A total of 5590 liver resections were done across 34 centres with a median annual centre volume of 35 (i.q.r. 20–69) procedures. Overall major morbidity and mortality rates were 11·2 and 2·0 per cent respectively. The mortality rate was 1·9 per cent after resection for colorectal liver metastases (CRLMs), 1·2 per cent for non-CRLMs, 0·4 per cent for benign tumours, 4·9 per cent for hepatocellular carcinoma and 10·3 per cent for biliary tumours. Higher-volume centres performed more major liver resections, and more resections for hepatocellular carcinoma and biliary cancer. There was no association between hospital volume and either major morbidity or mortality in multivariable analysis, after adjustment for known risk factors for adverse events. Conclusion: Hospital volume and postoperative outcomes were not associated

Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

Veilig stijgen en landen op Schiphol : actualisatie vergoedingsregeling graanteelt om ganzen te weren

In het Convenant reduceren risico vogelaanvaringen Schiphol 2016-2018 van maart 2016 is door een groot aantal partijen afspraken gemaakt om het aantal vogelaanvaringen met vliegtuigen rond Schiphol te verminderen. Het convenant is getekend door de Vereniging van Nederlandse Verkeersvliegers (VNV), Schiphol, Vereniging Natuurmonumenten, Staatsbosbeheer, Landschap Noord-Holland, Land- en Tuinbouworganisatie (LTO) Nederland, B&W Gemeente Haarlemmermeer, Gedeputeerde Staten van Noord-Holland, Zuid-Holland en Utrecht, en de Nederlandse Staat (vertegenwoordigd door de staatssecretaris van Infrastructuur en Milieu). In het convenant staan een aantal voornemens en maatregelen. Eén van de maatregelen is het zo veel mogelijk beperken van het foerageren van ganzen en andere vogels in de zomerperiode in de buurt van start- en landingsbanen. Het versneld onderwerken van graanresten kan hieraan een bijdrage leveren. Ganzen en andere vogels komen in de zomer na de graanoogst graankorrels zoeken en opeten. De afgelopen jaren is er een (vrijwillige) vergoedingsregeling geweest; hierbij zijn voor ruim 2.000 ha contracten afgesloten. De contracten lopen tot en met 2017. Voor de jaren na 2018 hebben de convenantpartijen gevraagd om opnieuw te kijken naar de opbouw van de verschillende posten voor het voorstel voor de basisvergoeding. Het ministerie van Infrastructuur en Milieu (I&M), afdeling Luchtvaartveiligheid, heeft deze adviesaanvraag bij het Wageningen Economic Research (voorheen LEI Wageningen UR) ingediend. Ook is gevraagd naar de ontwikkeling van het areaal granen in de afgelopen jaren in het gebied in vergelijking met het hele land en de ons omringende landen

Global-Detector; GIS- and Knowledge-based tool for a global detection of the potential for production, supply and demand

Wageningen Economic Research has developed Global-Detector, a knowledge-based Geographic Information System that aims to detect the worldwide potential for production, demand and market strategies. At any spot in the world Global-Detector can show the values from a large amount of indicators, such as climate, infrastructure, and land characteristics. A large set of indicators is readily available for use without any GIS-processing, and the model builder together with the expert can instantly start building the knowledge base for the concerning research aim. Knowledge from experts is applied to combine relevant indicators to create new indicators. The concept of Global-Detector and 10 applications developed by this tool are described. As a generic tool with increased flexibility, Global-Detector has many application possibilities in a wide variety of fields

Global-Detector; GIS- and Knowledge-based tool for a global detection of the potential for production, supply and demand

Wageningen Economic Research has developed Global-Detector, a knowledge-based Geographic Information System that aims to detect the worldwide potential for production, demand and market strategies. At any spot in the world Global-Detector can show the values from a large amount of indicators, such as climate, infrastructure, and land characteristics. A large set of indicators is readily available for use without any GIS-processing, and the model builder together with the expert can instantly start building the knowledge base for the concerning research aim. Knowledge from experts is applied to combine relevant indicators to create new indicators. The concept of Global-Detector and 10 applications developed by this tool are described. As a generic tool with increased flexibility, Global-Detector has many application possibilities in a wide variety of fields