Evaluating CERES and IXIM, the maize simulation models in DSSAT v4.5 under irrigated Mediterranean conditions

Computer simulation is a cost-effective methodology to examine the results of alternative crop management practices on agricultural production, estimate the use efficiency of resources, and assess the sustainability of cropping systems. Confident use of simulation models depends on the continuous improvement of these tools and the adequate calibration to local conditions. The Decision Support System for Agrotechnology Transfer (DSSAT) is a simulation environment providing models for 25 crops. The newest version of DSSAT, version 4.5, gives users the opportunity to choose between two maize models, CSM-CERES, and CSM-IXIM a more mechanistic model. In this work we compare the simulations of crop growth and yield obtained with these crop models in two high yielding irrigated cropping systems of Mediterranean climate in Spain

Crecimiento y eficiencia de uso del nitrógeno en maíz de regadío en una región semiárida según la fertilización nitrogenada utilizada

The main groundwater pollution factor in irrigated maize production areas is leaching of nitrogen below the root zone. During the years 1999-2001, experiments were carried out on irrigated maize in the semiarid region of Castilla- La Mancha to evaluate the effect of nitrogen in the growth and yield of maize. Three rates of nitrogen were tested: No (0 kg N ha-1), Nop (175, 150 and 130 kg N ha-1 in 1999, 2000 and 2001, respectively), and Nc (300 kg N ha-1). A high initial level of residual soil NO-3 was found in the spring of 1999 as a consequence of fertilization carryover from the previous years. Although there was no plant response to N fertilization in 1999, significant responses were obtained during the following two years. Moreover, in 2000, the grain production did not show significant differences between Nop and Nc. However, in 2001, maize yield was slightly decreased due to an attempt to decrease the Nop to 130 kg N ha-1, showing significant differences with regard to Nc. The differences in grain yield among nitrogen levels were mainly due to a significant variation in maximum leaf area index, leaf area duration and crop growth rate. There was a decreasing pattern in nitrogen use efficiency values with increasing fertilizer rates, indicating that crop production could be sustained with lower fertilizer applications. Fertilizer practices must be revised in order to control and prevent insofar as possible water pollution in "La-Mancha Oriental" aquifer.El principal contaminante del agua subterránea en las áreas de regadío cultivadas de maíz es la lixiviación del nitrógeno. Durante los años 1999 a 2001 se han realizado ensayos en maíz regado en la región semiárida de Castilla-La Mancha, con el objetivo de evaluar su producción y crecimiento ante tres dosis de nitrógeno: No (0 kg N ha-1), Nop (175, 150 y 130 kg N ha-1 en 1999, 2000 y 2001, respectivamente), y Nc (300 kg N ha-1). El alto nivel inicial de NO-3 residual en el suelo durante la primavera de 1999, consecuencia de la fertilización anterior, propició la falta de respuesta a la fertilización con N. Sin embargo, se obtuvieron respuestas significativas los dos años siguientes. Además, en el año 2000, la producción de grano no registró diferencias significativas entre Nop y Nc. Sin embargo, disminuyó ligeramente la producción en el año 2001 al tratar de reducir la dosis óptima a 130 kg N ha-1, presentando diferencias significativas respecto a Nc. Este hecho fue debido, principalmente, a una variación significativa en el índice de área foliar máximo, la duración del área foliar y la tasa de crecimiento del cultivo. Las dosis más elevadas de fertilizante originaron una disminución de la eficiencia de uso del nitrógeno, por lo que la producción podría obtenerse con unos aportes menores de nitrógeno. Se debe revisar la fertilización para contribuir a controlar y prevenir, en la medida de lo posible, la contaminación en el acuífero de La Mancha Oriental

Immune response in rabbits to two sizes of cysts of sarcocystis aucheniae

El objetivo del estudio fue evaluar la respuesta inmune de macroquistes pequeños y grandes de Sarcocystis aucheniae utilizando tres protocolos de inoculación. Para la obtención del antígeno se recolectaron cuellos de alpaca con quistes de S. aucheniae del camal de Huancavelica, Perú. Los quistes colectados fueron clasificados según el tamaño, en macroquistes grandes (>5 mm) y pequeños (1-3 mm), obteniéndose una concentración de proteína antigénica de 3.23 y 2.45 mg/ml, respectivamente. Treinta conejos fueron inmunizados con 0.05 mg/kg de proteína antigénica derivada de cada tamaño de macroquiste. Además, se consideró tres protocolos de inoculación (n = 5 conejos). El protocolo I y II con uno y dos meses de duración, respectivamente, donde las proteínas antigénicas fueron inactivadas con formol, y el protocolo III de 2 meses, con proteína antigénica inactivada con calor. La respuesta inmune específica Ag-Ac fue detectada con la prueba de inmunodifusión doble de agar gel en el 100% con los protocolos I y II, y 60% con el protocolo III en el caso de macroquistes grandes; así como en 100, 60 y 40% de los conejos con los protocolos I, II y III para macroquistes pequeños, respectivamente. En conclusión, respuestas inmunes del 86.6 y 66.6% fueron evidenciadas utilizando proteínas antígénicas provenientes de macroquistes grandes y pequeños, respectivamente, al utilizar los tres protocolos de inmunización, aunque en el análisis de Fisher no se observó asociación entre protocolos y reacción Ag-Ac.The aim of this study was to evaluate the immune response of small and large macrocysts of Sarcocystis auchenie using three protocols of inoculation. Alpaca meat samples with S. aucheniae were obtained from the slaughterhouse of Huancavelica, Peru. Cysts were collected and classified by size in large (>5 mm) and small (1-3 mm), obtaining 3.23 and 2.45 mg/ml respectively of antigenic protein by the Biuret method. Fifteen rabbits were immunized with 0.05 mg/kg of antigenic protein derived from large and small macrocysts. Besides, three protocols of inoculation were considered (n = 5 rabitts). Protocol I and II were of 1 and 3 month length where proteins were inactivated with formalin, and protocol III of 2 months length using heat-inactivated antigen protein. Specific immune response Ag-Ab was detected by double immunodiffusion in agar gel in 100% of rabbits using protocols I and II and 60% with protocol III in large macrocysts while 100, 60 and 40% response in protocols I, II and III in small macrocysts respectively. In conclusion, immune responses of 86.6 and 66.6% were obtained when using antigenic proteins from large and small cysts, respectively; however, no association was observed between protocols and Ag-Ab reaction when using Fisher’s analysis

Sensibilidade a carrapaticidas em populações de Rhipicephalusmicroplus da região sudeste do país.

Rhipicephalus microplus é considerado um grande entrave para a pecuária leiteira e de corte no mundo, uma vez que seu controle através do uso de carrapaticida tem se tornado uma difícil tarefa devido à seleção de populações resistentes

Atividade carrapaticida do alfa-bisabolol sobre populações de Rhipicephalus microplus (acari: ixodidae) com diferentes perfis de resistência.

O presente estudo teve como objetivo investigar a atividade acaricida do alfa-bisabolol sobre populações de Rhipicephalus microplus, com diferentes perfis de resistência.Evento online

AgroTutor: A Mobile Phone Application Supporting Agricultural Sustainable Intensification

Traditional agricultural extension services rely on extension workers, especially in countries with large agricultural areas. In order to increase adoption of sustainable agriculture, the recommendations given by such services must be adapted to local conditions and be provided in a timely manner. The AgroTutor mobile application was built to provide highly specific and timely agricultural recommendations to farmers across Mexico and complement the work of extension agents. At the same time, AgroTutor provides direct contributions to the United Nations Sustainable Development Goals, either by advancing their implementation or providing local data systems to measure and monitor specific indicators such as the proportion of agricultural area under productive and sustainable agriculture. The application is freely available and allows farmers to geo-locate and register plots and the crops grown there, using the phone’s in-built GPS, or alternatively, on top of very high-resolution imagery. Once a crop and some basic data such as planting date and cultivar type have been registered, the app provides targeted information such as weather, potential and historical yield, financial benchmarking information, data-driven recommendations as well as commodity price forecasts. Farmers are also encouraged to contribute in-situ information, e.g., soils, management, and yield data. The information can then be used by crop models, which, in turn, would send tailored results back to the farmers. Initial feedback from farmers and extension agents has already improved some of the app’s characteristics. More enhancements are planned for inclusion in the future to increase the app’s function as a decision support tool

AgroTutor: A Mobile Phone Application Supporting Sustainable Agricultural Intensification

Traditional agricultural extension services rely on extension workers, especially in countries with large agricultural areas. In order to increase adoption of sustainable agriculture, the recommendations given by such services must be adapted to local conditions and be provided in a timely manner. The AgroTutor mobile application was built to provide highly specific and timely agricultural recommendations to farmers across Mexico and complement the work of extension agents. At the same time, AgroTutor provides direct contributions to the United Nations Sustainable Development Goals, either by advancing their implementation or providing local data systems to measure and monitor specific indicators such as the proportion of agricultural area under productive and sustainable agriculture. The application is freely available and allows farmers to geo-locate and register plots and the crops grown there, using the phone’s built-in GPS, or alternatively, on top of very high-resolution imagery. Once a crop and some basic data such as planting date and cultivar type have been registered, the application provides targeted information such as weather, potential and historical yield, financial benchmarking information, data-driven recommendations, and commodity price forecasts. Farmers are also encouraged to contribute in-situ information, e.g., soils, management, and yield data. The information can then be used by crop models, which, in turn, send tailored results back to the farmers. Initial feedback from farmers and extension agents has already improved some of the application’s characteristics. More enhancements are planned for inclusion in the future to increase the application’s function as a decision support tool