Fuentes y niveles de materia orgánica en condiciones de invernadero

Universidad Nacional Agraria La Molina. Facultad de Agronomía. Departamento Académico de SuelosEl presente ensayo se realizó en el Laboratorio e invernadero de Fertilidad de Suelos que pertenece a la Facultad de Agronomía, ubicado en la Universidad Nacional Agraria La Molina. Se evaluó el efecto de la aplicación de siete fuentes de materia orgánica: compost sin moler, compost molido, gallinaza 1er uso, gallinaza 3er uso, gallinaza 6to uso, koripacha y vermicompost; a dos niveles 1% y 2% de fertilización, en un suelo arenoso, también se incluyó en el experimento tratamientos utilizando fertilizantes minerales, a una dosis de 300-300-300 ppm de NPK, usando los fertilizantes: urea, superfosfato triple y cloruro de potasio. Las variables evaluadas fue altura, materia seca total, extracción total de nitrógeno, extracción total de fósforo y extracción total de potasio utilizando el maíz PM-213 como cultivo indicador. Se utilizó un arreglo factorial de 7x2 con tres repeticiones en un Diseño Completamente al Azar (DCA). Los resultados del estudio demostraron que la materia orgánica que presento mayor altura y mayor extracción total de fósforo en el maíz fueron la gallinaza 1er uso al 1% y gallinaza 6to uso al 2%, asimismo la mayor materia seca total y la mayor extracción de nitrógeno en el maíz lo obtuvieron el compost molido al 1% y compost sin moler al 2%, finalmente en la variable extracción total de potasio ninguna materia orgánica presento diferencias significativas al nivel 1% y 2%.Tesi

Development of a novel plant water status indicator based on leaf spectrum

[SPA] El potencial hídrico de tallo es el indicador más comúnmente utilizado para evaluar el estado hídrico de las plantas debido a su elevada sensibilidad a la demanda climática y al régimen de riego, a pesar de su baja escala espacial y temporal. El objetivo de nuestro trabajo fue evaluar otros indicadores, como la firma espectral a nivel foliar emitida por mandarinos adultos sometidos a distintas intensidades de estrés hídrico, que nos permitan estimar el estado hídrico del cultivo a una mayor escala. La emisión de radiaciones de longitud de onda de 1000 nm, y el rango entre 1540-1740 nm (SWIR) permitieron diferenciar los niveles de estrés de manera significativa. A través de la combinación de distintas longitudes de onda y estructuras de índice identificamos un nuevo indicador altamente sensible al estado hídrico, denominado Índice de Relación Infrarrojo Visible (VIRI), muy bien correlacionado con el potencial hídrico de tallo. Este índice podría ser un complemento válido para la programación del riego a una escala mayor de parcela. [ENG] Stem water potential is the most used indicator to assess plant water status due to its high sensitivity to climatic demand and irrigation regime, despite its low spatial and temporal scale. The aim of our work was to evaluate other indicators, such as the leaf-scale spectrum emitted by adult mandarin trees subjected to different water stress intensities, which allow us to estimate the plant water status at a larger scale. The emission of radiation at a wavelength of 1000 nm, and the range between 1540-1740 nm (SWIR) allowed us to differentiate the levels of stress in a significant way. Through the combination of different wavelengths and index structures we identified a new indicator highly sensitive to water status, called Visible Infrared Ratio Index (VIRI), which correlates very well with stem water potential. This index could be a valid complement for irrigation scheduling at a larger plot scale.Este estudio fue financiado por la Comisión Europea (Proyecto DIVERFARMING, H2020-RUR-06-2016) y la Agencia Nacional de Investigación de España (PID2019-106226RB-C22)

Mineral nitrogen fertilization effect on broccoli crop yield and physiology

[SPA] El brócoli es considerado un cultivo que requiere altas cantidades de nitrógeno (N) para alcanzar su potencial productivo, puesto que el N es el macronutriente más determinante para el desarrollo y rendimiento de la producción agrícola. Asimismo, el uso del N puede presentar un impacto negativo sobre el medioambiente, incluso bajo estrategias eficientes de fertirrigación. Por ello, el objetivo principal de este trabajo fue determinar la dosis más adecuada de N para maximizar el uso eficiente del N por el cultivo, con el menor impacto posible en el medioambiente. Se establecieron 3 tratamientos basados en diferentes coeficientes de extracción de N por el cultivo: 9,0, 7,3 y 5,7 kg de N por t recolectada y se determinó el efecto sobre el intercambio gaseoso foliar y rendimiento. El coeficiente de extracción más restrictivo no afectó significativamente la actividad fisiológica de las plantas, producción ni características físicas de las pellas recolectadas. [ENG] Broccoli is considered a crop that requires high amounts of nitrogen (N) to reach its productive potential, since N is the most determining macronutrient for the development and performance of agricultural production. Moreover, N use can have a negative impact on the environment, even under efficient fertigation strategies. Therefore, the main objective of this work was to determine the most adequate N dose to maximize the efficient use of N by the crop, with the least possible impact on the environment. Three treatments were established based on different N extraction coefficients for the crop: 9.0, 7.3, and 5.7 kg of N per t harvested, and the effect on leaf gas exchange and yield was determined. The most restrictive extraction coefficient did not significantly affect plant physiological activity, yield or physical characteristics of the harvested heads.Estos resultados se enmarcan en el proyecto “Nuevas técnicas para mejorar la eficiencia de la fertirrigación mediante el uso de inhibidores de la nitrificación en cultivos hortícolas de la Región de Murcia” ejecutado por el Grupo Operativo de Nutrición Vegetal Sostenible (GO-NUVES), financiado por el Programa de Desarrollo Rural de la Región de Murcia y con participación del Fondo Europeo Agrícola de Desarrollo Rural y el Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente del Gobierno de España. Asimismo, se agradece la colaboración a las empresas participantes y colaboradores integrantes del GO-NUVES

Effect of the use of nitrification inhibitors on the growth and production of ‘Iceberg’ lettuce

[SPA] El uso de inhibidores de la nitrificación (IN) permite incrementar la sostenibilidad de la fertilización nitrogenada puesto que pueden reducir la lixiviación de nitrógeno en forma de nitrato. No existe consenso sobre el efecto de la incorporación de IN sobre el rendimiento de los cultivos dada la sensibilidad de algunos al amonio, tal es el caso de lechuga. Se realizó un cultivo de lechuga durante otoño-invierno en Cartagena (Murcia) para determinar el efecto de la incorporación de DMPP y DCD en la fertirrigación de lechuga sobre el crecimiento y rendimiento del cultivo. No se detectaron diferencias respecto al control ni entre los IN utilizados sobre el crecimiento durante el ciclo de cultivo, la producción ni la aptitud para la agroindustria. [ENG] The use of nitrification inhibitors (NI) increases the sustainability of nitrogen fertilization since they can reduce leaching of nitrogen as nitrate. There is no consensus on the effect of NI incorporation on crop yield given the sensitivity of some crops to ammonium, such as lettuce. A lettuce crop was grown during autumn-winter in Cartagena (Murcia) to determine the effect of the incorporation of DMPP and DCD in lettuce fertirrigation on the growth and yield. No differences were detected regarding control or between the NI used on growth during the crop cycle, yield or suitability for agro-industry.Estos resultados se enmarcan en el proyecto “Nuevas técnicas para mejorar la eficiencia de la fertirrigación mediante el uso de IN en cultivos hortícolas de la Región de Murcia” ejecutado por el Grupo Operativo de Nutrición Vegetal Sostenible: NUVES y financiado por el Programa de Desarrollo Rural de la Región de Murcia y con participación del Fondo Europeo Agrícola de Desarrollo Rural y el Ministerio de Agricultura y Pesca, Alimentación y Medio Ambiente del Gobierno de España. Asimismo, se agradece a los socios participantes y colaboradores integrantes del GO-NUVES

Sensitivity to water deficit of the second stage of fruit growth in late mandarin trees

In citrus fruits, phases I and II of fruit growth are sensitive to water deficit, and for this reason, deficit irrigation (DI) has been usually restricted to the final ripening phase. However, the optimal timing and intensity of stress during sensitive phases have not been clearly defined. The main objective was to determine the sensitivity of the second stage of fruit growth to water deficit in adult mandarin trees, and to explore the suitability of different soil and plant water status indicators, including the leaf-scale spectrum, according to the water stress level. Four irrigation treatments were tested: a control (CTL) irrigated at ~ 80% of ETc during the entire crop cycle, and three irrigation suppression treatments, in which no water was applied during the end of phase I and the beginning of phase II (DI1), the second half of phase II (DI2), and phase III of fruit growth (DI3), respectively. Phase II of fruit growth can be considered as a non-critical phenological period until the fruit reaches approximately 60% of its final size, with the application of a water deficit using an irrigation threshold of midday stem water potential of − 1.8 MPa, and a cumulative water stress integral close to 28 MPa day. The novel visible infrared ratio index (VIRI) showed a high sensitivity for trees subjected to moderate and severe water stress and can be complementarily used to estimate on a larger temporal and spatial scale the plant water status. Wavelengths in the short-wave infrared (SWIR) region allowed differentiation between non-stressed, moderately, and severely water-stressed trees, and can be considered as an initial basis for determining the water status of mandarin trees at various stress intensities by remote sensing.This study was supported by the European Commission H2020 (Grant 728003, DIVERFARMING Project) and National Research Agency of Spain (PID2019-106226RB-C22)

Sustainable Strategies to Prevent Iron Deficiency, Improve Yield and Berry Composition in Blueberry (Vaccinium spp.)

The aim of this investigation was to study the effect of sustainable strategies to correct iron deficiency in blueberries, based on Fe-heme applications or intercropping with graminaceous species, on yield, and berry quality variables. The experiment was conducted in a blueberry orchard established in a sub-alkaline soil. The association with grasses increased the crop load and yield (only Festuca rubra), and decreased the skin/flesh ratio. In addition, these treatments increased anthocyanins as well as some hydroxybenzoic acids, hydroxycinnamic acids, flavanols, and flavonol concentrations in skins with a similar effectiveness as Fe-EDDHA, whereas the Fe-heme applications did not influence such parameters. Moreover, data revealed that the association with both grasses decreased the firmness of the berries, whereas none of the treatments assessed changed the soluble solids, pH, acidity, and the soluble solids/acidity rate compared to the control. These results suggest that Fe nutrition is crucial for yield and berry quality in blueberry, and that intercropping with grasses may be an effective and sustainable alternative to counteract Fe deficiency in blueberry, with a similar effect on berries to that achieved with Fe-EDDHA

Soil greenhouse gas emissions and crop production with implementation of alley cropping in a Mediterranean citrus orchard

The implementation of alley cropping in orchards has been suggested as a sustainable strategy to increase farmer revenues by crop diversification, enhance soil organic matter (SOM) and fertility, water retention, overall biodiversity, and contribute to climate change mitigation. Thus, the objective of this study was to assess if alley cropping with annual crops can contribute to i) mitigate soil greenhouse gas (GHG) emissions, ii) enhance C sequestration in a semiarid Mediterranean irrigated citrus orchard, and iii) increase land productivity. For this, two different treatments were established: i) conventional mandarin monoculture (MC) with no alley cropping; and ii) mandarin diversified with alley cropping of barley/vetch and fava bean (DIV). Measurements of soil CO2 and N2O emissions were periodically performed (every 7–20 days) during two years. Soil CO2 emission rates followed the soil moisture trend, and showed no significant differences between treatments. As an average, soil CO2 emission rates were 147 mg m-2 h-1 in MC and 196 mg m-2 h-1 in DIV. Soil N2O emission rates were not correlated to soil moisture nor temperature, and showed average values of 0.026 mg m-2 h-1 in MC and − 0.002 mg m-2 h-1 in DIV. Alley cropping did not contribute to significantly increase soil organic C and total nitrogen in two years’ time. With regard to production, mandarin yield showed no significant differences between treatments, but alley crops contributed to complementary commodities to the main cash crop, increasing overall land productivity. Thus, alley cropping in irrigated Mediterranean orchards has no significant effect on soil C sequestration and GHG emissions at short-term, with increased land productivity owing to new commodities grown in the alleys. These results confirm that under semiarid Mediterranean climate, long periods are needed to efficiently assess soil C sequestration potential of sustainable practices in orchards.This work was supported by the European Commission Horizon 2020 Project Diverfarming [Grant agreement 728003]. Raúl Zornoza acknowledges the financial support from the Spanish Ministry of Science, Innovation and Universities through the “Ramón y Cajal” Program [RYC-2015-18758]

New techniques to improve fertigation efficiency with nitrification inhibitors in lettuce (Lactuca sativa L.) in Murcia

[SPA] El nitrógeno (N) es un elemento esencial para el crecimiento de las plantas y es el nutriente que se suele aplicar en mayor cantidad en la agricultura, pero se puede perder una cantidad significativa por la lixiviación, emisiones gaseosas y volatilización de NH3; aumentando los costos de producción e impactando negativamente sobre el medio ambiente. Los inhibidores de la nitrificación (IN) permiten reducir estas pérdidas, simplificar la tarea de fertilización, disminuir costos y facilitar una mayor flexibilidad en el tiempo de aplicación. La problemática esencial de los cultivos hortícolas en Murcia es el manejo optimizado de agua y nutrientes por lo que la incorporación de IN debe someterse a protocolos que aún no están definidos en la agricultura intensiva. El objetivo general de la investigación es elaborar desde un punto de vista multidisciplinar criterios eficientes y sostenibles para el manejo de la fertirrigación de lechuga mediante el uso de fertilizantes con IN y la monitorización del sistema suelo-planta-atmósfera, para mejorar la eficiencia del uso del agua y nutrientes, cumplir los estándares de calidad exigidos para la exportación y disminuir la emisión de gases de efecto invernadero según las condicionantes edafoclimáticas locales de Murcia. [ENG] Nitrogen (N) is an essential element for the growth of plants and is the nutrient that is usually applied in greater quantity in agriculture, but a significant amount can be lost through leaching, gaseous emissions and volatilization of NH3; increasing production costs and negatively impacting the environment. The nitrification inhibitors (NI) allow reducing these losses, simplifying the fertilization management, reducing costs and facilitating greater flexibility in the time of application. The essential problem of horticultural crops in Murcia is the optimized management of water and nutrients, so the incorporation of NI must be subject to protocols that are not yet defined in intensive agriculture. The general objective of the research is to develop, from a multidisciplinary point of view, efficient and sustainable criteria for the management of lettuce fertigation through the use of NI fertilizers and the monitoring of the soil-plant-atmosphere system, to improve the efficiency of the use of water and nutrients, meet the quality standards required for export and reduce the emission of greenhouse gases according to the local edaphoclimatic conditions of Murcia

Divergent patterns of meiotic double strand breaks and synapsis initiation dynamics suggest an evolutionary shift in the meiosis program between American and Australian marsupials

In eutherian mammals, hundreds of programmed DNA double-strand breaks (DSBs) are generated at the onset of meiosis. The DNA damage response is then triggered. Although the dynamics of this response is well studied in eutherian mammals, recent findings have revealed different patterns of DNA damage signaling and repair in marsupial mammals. To better characterize these differences, here we analyzed synapsis and the chromosomal distribution of meiotic DSBs markers in three different marsupial species (Thylamys elegans, Dromiciops gliorides, and Macropus eugenii) that represent South American and Australian Orders. Our results revealed inter-specific differences in the chromosomal distribution of DNA damage and repair proteins, which were associated with differing synapsis patterns. In the American species T. elegans and D. gliroides, chromosomal ends were conspicuously polarized in a bouquet configuration and synapsis progressed exclusively from the telomeres towards interstitial regions. This was accompanied by sparse H2AX phosphorylation, mainly accumulating at chromosomal ends. Accordingly, RAD51 and RPA were mainly localized at chromosomal ends throughout prophase I in both American marsupials, likely resulting in reduced recombination rates at interstitial positions. In sharp contrast, synapsis initiated at both interstitial and distal chromosomal regions in the Australian representative M. eugenii, the bouquet polarization was incomplete and ephemeral, γH2AX had a broad nuclear distribution, and RAD51 and RPA foci displayed an even chromosomal distribution. Given the basal evolutionary position of T. elegans, it is likely that the meiotic features reported in this species represent an ancestral pattern in marsupials and that a shift in the meiotic program occurred after the split of D. gliroides and the Australian marsupial clade. Our results open intriguing questions about the regulation and homeostasis of meiotic DSBs in marsupials. The low recombination rates observed at the interstitial chromosomal regions in American marsupials can result in the formation of large linkage groups, thus having an impact in the evolution of their genomesThis work was supported by grants CGL 2014-53106-P to JP (Ministerio de Ecomonía y Competitividad, Spain), BIOUAM02- 2020 to JP and RG (Departamento de Biología, Universidad Autónoma de Madrid), PID 2020-112557 GB-I00 to AR-H. (Ministerio de Ciencia e Innovación, Spain) and from the Australian Research Council to MBR, GS, and PDW. (DP21103512 and DP220101429). PW is also supported by the NHMRC (APP1182667 and APP2021172). LM-G was supported by a FPU predoctoral fellowship from the Ministry of Science, Innovation and University (FPU18/03867