Aquaponics: integrating fish feeding rates and ion waste production for strawberry hydroponics

Aquaponics is the science of integrating intensive fish aquaculture with plant production in recirculating water systems. Although ion waste production by fish cannot satisfy all plant requirements, less is known about the relationship between total feed provided for fish and the production of milliequivalents (mEq) of different macronutrients for plants, especially for nutrient flow hydroponics used for strawberry production in Spain. That knowledge is essential to consider the amount of macronutrients available in aquaculture systems so that farmers can estimate how much nutrient needs to be supplemented in the waste water from fish, to produce viable plant growth. In the present experiment, tilapia (Oreochromis niloticus L.) were grown in a small-scale recirculating system at two different densities while growth and feed consumption were noted every week for five weeks. At the same time points, water samples were taken to measure pH, EC25, HCO3 – , Cl – , NH4 + , NO2 – , NO3 – , H2PO4 – , SO4 2– , Na + , K+ , Ca 2+ and Mg 2+ build up. The total increase in mEq of each ion per kg of feed provided to the fish was highest for NO3 - , followed, in decreasing order, by Ca 2+ , H2PO4 – , K+ , Mg 2+ and SO4 2– . The total amount of feed required per mEq ranged from 1.61- 13.1 kg for the four most abundant ions (NO3 – , Ca 2+ , H2PO4 – and K+ ) at a density of 2 kg fish m–3 , suggesting that it would be rather easy to maintain small populations of fish to reduce the cost of hydroponic solution supplementation for strawberries

Real cases study through computer applications for futures Agricultural Engineers

One of the huge concerns on the higher engineer education is the lag of real cases study that the future professionals need in the work and corporation market. This concern was reflected in Bologna higher education system including recommendations in this respect. The knowhow as why this or other methodology is one of the keys to resolve this problem. In the last courses given in Department of Crop Production, at the Agronomy Engineer School of Madrid (Escuela Técnica Superior de Ingenieros Agrónomos, UPM) we have developed more than one hundred applications in Microsoft Excel®. Our aim was to show different real scenarios which the future Agronomic Engineers can be found in their professional life and with items related to crop production field. In order to achieve our target, each application in Excel presents a file text in which is explained the theoretical concepts and the objectives, as well as some resources used from Excel syntax. In this way, the student can understand and use of such application, even they can modify and customize it for a real case presented in their context and/or master project. This electronic monograph gives an answer to the need to manage data in several real scenarios showed in lectures, calculus resolution, information analysis and manage worksheets in a professional and student level

El papel del nitrógeno en agricultura. Zonas vulnerables al nitrato

El nitrógeno, cuyo símbolo químico es N, fue descubierto como elemento químico independiente en 1772, por el médico, químico y botánico escocés Daniel Rutherford (1749-1819). El N representa aproximadamente el 78 % del aire atmosférico que respiramos, donde se encuentra mayoritariamente en forma molecular (N2). En la corteza terrestre se encuentra en forma de nitrato sódico (NaNO3, nitrato de Chile), o nitrato potásico (KNO3, salitre). En su forma molecular se comporta como un gas sin color (incoloro) olor (inodoro) ni sabor (insípido) y es muy poco reactivo, lo que le convierte en un gas prácticamente inerte. En la Tabla 1 se muestran los principales compuestos minerales presentes en la Naturaleza que contienen N en su composición química; además de los compuestos minerales indicados en la Tabla 1, el N forma parte de las proteínas, de los ácidos nucleicos (ADN y ARN) y de otras muchas moléculas orgánicas que son indispensables para la vida de las planta

Responses of reference evapotranspiration to changes in atmospheric humidity and air temperature in Spain

We studied the sensitivity of reference evapotranspiration (ETo) to global warming in Spain at the end of the 21st century. The FAO-56 Penman-Monteith equation was used to estimate ETo, and we examined the sensitivity of the latter to changes in temperature and relative humidity. Changes in stomatal resistance in response to increased CO2 concentration were not evaluated, nor were the changes in wind velocity and solar radiation. Different scenarios were used for estimation of future ETo in different river basins as a consequence of trends in the maximum and minimum temperatures and maximum and minimum humidities during the period 1973–2002, as observed from 38 meteorological stations. The temperature increases ranged between 0.3 and 0.7°C decade – 1 , and the relative humidities fluctuated between 0.1 and –3.7% decade – 1 Four scenarios were simulated that . considered the variations in linear tendency of the maximum and minimum temperatures and maximum and minimum relative humidities. The trends of the 4 scenarios were incorporated with the data from 338 agrometeorological stations to estimate future ETo. In all cases, there was an annual increase in ETo of 11, 21, 36 and 7% above the annual ETo (1196 mm) for Scenarios 0, 1, 2 and 3, respectively. The river basin most affected by these changes was the Ebro River valley. The most affected months were May, June, July and August, while the least affected months were November, December and Januar

Análisis de la absorción y almacenamiento de perclorato presente en fertilizantes en melón y sandía bajo cubierta

Análisis de la absorción y almacenamiento de perclorato presente en fertilizantes en melón y sandía bajo cubiert

Future reference evapotranspiration in Duero Valley (Spain)

The impact of climate change and its relation with evapotranspiration was evaluated in the Duero River Basin (Spain). The study shows the possible future situations 50 years from now from the reference evapotranspiration (ETo). The maximum temperature (Tmax), minimum temperature (Tmin), dew point (Td), wind speed (U) and net radiation (Rn) trends during the 1980-2009 period were obtained and extrapolated with the FAO-56 Penman- Montheith equation to estimate ETo. Changes in stomatal resistance in response to increases in CO2 were also considered. Four scenarios were done, considering the concentration of CO2 and the period analyzed (annual or monthly). The scenarios studied showed the changes in ETo as a consequence of the annual and monthly trends in the variables Tmax, Tmin, Td, U and Rn with current and future CO2 concentrations (372 ppm and 550 ppm). The future ETo showed increases between 118 mm (11%) and 55 mm (5%) with respect to the current situation of the river basin at 1042 mm. The months most affected by climate change are May, June, July, August and September, which also coincide with the maximum water needs of the basin?s crop

Analizador electrónico de calidad de semillas

Analizador electrónico automático de calidad de semillas. El Analizador Electrónico Automático de Calidad de Semillas resuelve el problema de la determinación a priori de la calidad de un lote de semillas en virtud de su vigor para la germinación. Este análisis es realizado de forma automática mediante la medida de la conductividad eléctrica generada por la imbibición de semillas en agua desionizada. Presenta como ventajas la posibilidad de realizar múltiples medidas sobre lotes diferentes de forma paralela y automática, la modularidad de sus componentes que permite su limpieza y sustitución en caso de fallo y la conexión directa a ordenador personal para el almacenamiento de los datos y la generación de informes de calidad tras un análisis estadístico y matemático. El sistema puede ser programado para la realización de una campaña de medidas evitando la necesidad de la presencia de un supervisor. Todo ello lo hace un equipo completo y novedoso

Trends in climatic variables and future reference evapotranspiration in Duero Valley (Spain)

The impact of climate change and its relation with evapotranspiration was evaluated in the Duero River Basin (Spain). The study shows possible future situations 50 yr from now from the reference evapotranspiration (ETo). The maximum temperature (Tmax), minimum temperature (Tmin), dew point (Td), wind speed (U) and net radiation (Rn) trends during the 1980–2009 period were obtained and extrapolated with the FAO-56 Penman-Montheith equation to estimate ETo. Changes in stomatal resistance in response to increases in CO2 were also considered. Four scenarios were done, taking the concentration of CO2 and the period analyzed (annual or monthly) into consideration. The scenarios studied showed the changes in ETo as a consequence of the annual and monthly trends in the variables Tmax, Tmin, Td, U and Rn with current and future CO2 concentrations (372 ppm and 550 ppm). The future ETo showed increases between 118 mm (11 %) and 55 mm (5 %) with respect to the current situation of the river basin at 1042 mm. The months most affected by climate change are May, June, July, August and September, which also coincide with the maximum water needs of the basin’s crop

Idoneidad de la iluminación con led y oled de estado sólido para el cultivo del azafrán (Croccus Sativus l.) en invernaderos

Cormos de azafrán (Croccus sativus L.) fueron analizados morfológicamente y se cultivaron de forma hidropónica a 16 - 21 ºC. Con el fin de estudiar el efecto de la radiación electromagnética de color azul (435 nm), roja (660 nm) y del rojo lejano (730 nm) sobre la fotosíntesis y la morfogénesis del azafrán, se utilizaron diodos emisores de luz (LED) fabricados por PHILIPS (mod. GreenPower LED High Flux). La intensidad de iluminación que recibió el cultivo se ajustó a la que recibiría en condiciones naturales mediante un sistema electrónico de control, en el que se utilizan dimmers para el control del flujo luminoso. Los resultados obtenidos hasta este momento permiten señalar que, tanto la iluminación con luz azul y roja estimulan de forma significativa el crecimiento de los vástagos (parte aérea) frente a los cormos testigo (iluminación natural), si bien en ninguno de los tratamientos se ha producido la inducción floral que cabía esperar. Como una alternativa viable a los tradicionales LEDs inorgánicos, algunos de los nuevos experimentos utilizarán diodos orgánicos emisores de luz (OLED), basados en nuevos complejos de erbio octocoordinados y con emisiones en las regiones del rojo y del infrarrojo cercano

Nuevos métodos de obtención de bioqueroseno a partir de extractos de algas

A partir de biomasa de algas en forma de pasta y procedente de su centrifugación (Nanochloropsis gaditana, Ascophyllum Nodosum y Laminaria Digitata) se elabora por procedimiento de solvólisis un biodiesel susceptible de hidrogenación en bioquioqueroseno y para su posterior uso como combustible de aviones. Este trabajo investiga la composición de las algas en ácido algínico y en sus unidades constituyentes o ácidos manurónico y gulurónico, y el contenido en alginato de sodio sobre algas secas. La valorización de residuos procedentes de centrifugados de algas con bajo contenido en aceite, se ha mostrado útil para la extracción de los mismos, y posterior solvolisis ácida y extracción con disolventes (acetilacetona y el etilenglicol). Especialmente la espectroscopía 1 HNMR y 13 CNMR se ha mostrado útil para identificar en los aceites, ácidos grasos próximos al ácido cis-cis-9,12- octadecadienoico. Por esterificación y subsiguiente hidrogenación se produce el bioqueroseno objeto de estudi