Sustainable nitrogen fertilisation in sweet pepper: assessing growth and fruit quality and the potential nitrate pollution from different organic manures

BACKGROUND: The use of organic cultivation with manures does not avoid the risk of high nitrate concentrations if nutrient management is inefficient. So we studied the influence of three organic manures combined or not with additional chemical fertilisers on growth and yield of sweet pepper (Capsicum annuum L.), and on the soil and plant N concentrations. RESULTS: After 3 years of organic cultivation, poultry manure caused the highest soil pollution. The evolution of nitrate and organic matter in soil showed a pattern close to that of plant growth. The addition of mineral fertiliser increased vegetative growth and yield, and a cumulative season effect was observed. In treatments with no additional mineral fertiliser N translocation from leaves to fruits happened. A cumulative effect of seasons on fruit quality and a reduction near to 30% was observed in the first fruit quality category after 3 years. The fruit vitamin C content was reduced by increasing N fertilisation. CONCLUSION: The effects of organic fertiliser on soil and plant growth and yield depended on the type of manure used, its rate, and consecutive crop seasons. Horse manure gave the best combination of agricultural and environmental characteristics and could be used without additional fertigation.We thank Dr D.J. Walker for correction of the written English, G. Ortuno for assistance in the greenhouse and laboratory, A.J. García, and CDTT ‘‘El Mirador’’ for help in growing plants, the Fundacion Séneca de la Región de Murcia for project 08764/PI/08, and the European Social Fund

Response of plant growth to low calcium concentration in the nutrient solution

Many studies have indicated the importance of calcium in fruit disorders. This nutrient is often applied in the nutrient solution in relatively high amounts throughout the crop season, usually without taking into account the physiological stage of the plant. Our study aimed to determine the effect of calcium supply on growth of young, vegetative tomato plants. The experiment was carried out in a growth chamber under fully controlled climate conditions. Treatments consisted of four periods of 1, 3, 7 or 14 days of low calcium (0.5 meq l-1) compared with the control (9 me l-1). Plant dry matter content, total leaf area, leaf dry matter and specific leaf area were not affected after 14 days of low Ca supply. Ca concentrations in young leaves, stem, and roots were quickly reduced after only 1 day of low-Ca. After 14 days, Ca concentration in all plant organs (leaves, stems and roots) was reduced by approximately 70% compared to control plants. Stomatal regulation was not affected by this level of calcium stress as leaf transpiration in treated plants was similar to control plants with the same leaf area. Our data show that calcium supply and consequently Ca concentration in the plant can be reduced drastically without any adverse effect on growth

Regulation of growth and nutrient uptake under different transpiration regimes

To determine the extent to which air humidity affects the regulation of nutrient demand, an experiment with tomato plants was carried out under fully controlled climate conditions. Treatments consisted of three levels of relative air humidity (RH): 50%, 70% (control) and 95%, corresponding to 1.32, 0.79 and 0.13 kPa vapour pressure deficit (VPD), respectively. High humidity reduced the total plant dry matter, leaf dry weight, and total leaf area but no effect was found in leaf dry matter percentage. High humidity also increased the dry matter partitioning into the stems but reduced the dry matter partitioning into the leaves. Relative growth rate (RGR) was reduced by both high and low air humidity compared with the control with the stronger effect at 95%RH. Net assimilation rate (NAR) was more reduced than leaf area ratio (LAR) at low humidity, but at high humidity both parameters were affected to a similar extent. Water use efficiency (WUE) increased from 3.4 mgDM/ml H2O at 70%RH to 7.4 mgDM/ml H2O at 95%RH. The concentrations of N, K and Mg were not affected by humidity but concentrations of P, Ca and S in the plant were reduced at high humidity

Effect of Photoselective Shading Nets on Productivity and Economic Viability in Pepper Crops

In recent years, the use of photoselective shading nets to mitigate the harmful high radiation caused by the increase in temperatures is growing. The objective of this work was to study the positive effects - in terms of yield and profitability of photoselective shade nets in two types of pepper: Lamuyo (cultivars Alcudia and Pompeo) and California (cultivars Bendigo and Cayetano). The weekly yields, classified into different calibre, were analysed over two years, and for the analysis of economic profitability, the Equivalent Annual Value (EAV) was used with an analysis of sensitivity. The yields obtained with the pearl-colored net giving 30% shading were superior to open cultivation (no netting), in all the studied cultivars; in particular, Cayetano and Pompeo had 136 and 86% greater yields, respectively. This same trend was observed for the red-colored net giving 30% shading, with 88 and 74% increase in yield in Cayetano and Pompeo, respectively. In economic terms, the EAV was superior with the use of the pearl net, especially for the cultivars Alcudia and Cayetano - being €14,864 and €13,326 ha-1 yr-1, respectively. The yield and profitability were better for the crops grown under the pearl-colored photoselective net, especially for cultivars Alcudia and Cayetano. The sensitivity analysis showed that the probability of obtaining negative returns was higher in the absence of netting, while under the shade nets it was below 10%

Nitrogen fertilizer recommendations for sweet pepper crop in greenhouses of Campo de Cartagena

[SPA] En el año 1999 se diseñó un experimento en 8 lisímetros de drenaje de 7x7x0,90 m3 bajo invernadero, para estudiar la lixiviación de nitratos en un cultivo de pimiento. Desde el año 1999 hasta 2001 se han ensayado diferentes dosis de abonado mineral nitrogenado y desde el año 2002 hasta el 2006 diferentes técnicas de cultivo (ecológico, integrado y convencional), que han permitido evaluar las pérdidas de nitratos en el drenaje y obtener conclusiones sobre la producción, extrapolables a condiciones similares de suelo de la Comarca del Campo de Cartagena. Teniendo en cuenta los aportes de N del estiércol, el suelo y el agua y como resultado del estudio, se concluyó que con dosis de 1,5 UF de N mineral por tonelada de producción prevista (15 g N/m2 ) para una producción de 10 Tm/Ha (la media en la Comarca), combinado con el aporte de 4 kg de estiércol/m2, era suficiente para obtener buenas producciones con menor impacto medioambiental en comparación con las que se aplican en la Comarca y que están entre los 30 y 40 g N/m2. [ENG] In 1999 an experiment was designed in a greenhouse with eight drainage lysimeters (7x7x0.90 m) to study nitrate leaching in a sweet pepper crop. From 1999 to 2001 we tested different doses of mineral nitrogen fertilization and from 2002 to 2006 different farming techniques (organic, integrated and conventional). The aim of those experiments was to assess losses of nitrates from drainages and to study crop yield response as representative soil conditions in the region (Campo de Cartagena, Murcia, Spain). According to N supply, soil characteristics and water composition, we concluded that the supply of 15 g of N per m2, with the addition of 4 kg of manure was enough to maintain similar yield (10 t per ha) compared with traditional N-fertilizer practices in the region (30-40 g per m2). Our results can help to reduce the environmental impact of this crop.Esta investigación ha sido financiada por el INIA y el IMIDA Se agradece su colaboración en la cesión de los terrenos al Centro Integrado de Formación y Experiencias Agrarias de Torre-Pacheco (Murcia)

Balance de agua y nitrógeno en un cultivo de pimiento grueso en el Campo de Cartagena

Se diseñó un experimento consistente en la construcción de 8 lisímetros de drenaje bajo invernadero en Torre‐Pacheco. En los años 2003, 2004, 2005 y 2006 se ensayaron en dicho invernadero tres técnicas de cultivo diferentes (T‐E:ecológico, T‐I:integrado y T‐C:convencional) en pimiento grueso, que han permitido, contando con la información obtenida durante cuatro años sobre abonado nitrogenado y riego, evaluar las pérdidas de nitratos en el agua de drenaje. Los resultados permiten comprobar como es la relación entre el nitrógeno aportado y el lixiviado para los sistemas de cultivo estudiados, corroborando como una mayor cantidad de abonado se corresponde con una lixiviación de nitrógeno mayor, para las mismas dosis de riego; pero sin perder de vista que en las parcelas testigo, sin aportación de nitrógeno mineral, se han medido considerables lixiviaciones de nitratos, aunque menores que en las parcelas con abonado mineral. Durante el desarrollo de esta investigación se ha comprobado, además, que una disminución de las dosis de nitrógeno respecto a las normalmente utilizadas en la zona de estudio produce cosechas similares. La dosis de 15 g N/m2 de abono mineral (nitrato cálcico + nitrato potásico) combinada con el aporte de 4 kg/m2 de estiércol fermentado se ha mostrado como la más eficaz en relación con la producción. Todo ello indica que el tratamiento T‐E acompañado de aportes adicionales de nitrógeno mineral, inferiores a los realizados en los T‐I y T‐C, constituiría una fertilización óptima que aseguraría la producción y longevidad del cultivo de pimiento.Esta investigación ha sido financiada por el INIA durante los años 2004, 2005 y 2006 (Proyecto RTA‐04‐035, en colaboración con la Comunidad Autónoma) y el resto de los años con fondos propios del IMIDA. Se agradece su colaboración en la cesión de los terrenos al Centro Integrado de Formación y Experiencias Agrarias de Torre‐ Pacheco (Murcia)

Rootstock-mediated differential responses in the antioxidative metabolism of pepper plants subjected to salinity stress

[SPA] Se ha visto que, las respuestas diferenciales de crecimiento y productividad de portainjertos comerciales de pimiento están asociadas a cambios en el metabolismo hormonal en condiciones de estrés salino. En este estudio, tres parámetros fundamentales del metabolismo antioxidativo (peroxidación lipídica, concentración de fenoles totales y actividad ascorbato peroxidasa) se analizaron en hojas de plantas de pimiento (Gacela F1) sin injertar e injertadas sobre tres portainjertos comerciales (Atlante, Creonte y Terrano), y se cultivaron en condiciones control (0 mM NaCl) y salinas (35 mM NaCl). La salinidad no afectó significativamente ni a la peroxidación lipídica ni a la concentración de fenoles totales. Sin embargo, las plantas injertadas sobre los tres portainjertos comerciales presentaron una reducción significativa de la peroxidación lipídica, que amortiguó el daño oxidativo provocado por el estrés salino. La actividad ascorbato peroxidasa se vio reducida en condiciones de salinidad, especialmente en plantas injertadas sobre Atlante, mientras que las plantas injertadas sobre Terrano presentaron una actividad ascorbato peroxidasa significativamente superior al resto de combinaciones. Este estudio muestra que existen respuestas diferenciales en el metabolismo antioxidativo en plantas de pimiento sometidas a estrés salino que podrían explicar las diferencias en crecimiento y productividad observadas. [ENG] Contrasting growth and yield responses of pepper rootstocks have been associated with changes in the hormonal balance under moderate salinity. In the present study, three important antioxidative metabolism-related parameters (lipid peroxidation, total phenol concentration, and ascorbate peroxidase activity) were analysed in leaves of pepper plants (Gacela F1) either non-grafted or grafted onto three commercial rootstocks (Atlante, Creonte, and Terrano) and cultivated under control (0 mM NaCl) and moderate salinity conditions (35 mM NaCl). Salinity did not significantly alter either lipid peroxidation or total phenol concentration except for plants grafted onto Terrano, which showed the highest phenol concentrations. Importantly, plants grafted onto the three commercial rootstocks significantly decreased lipid peroxidation, thus buffering the damage caused by oxidative stress under salinity with respect to the non-grafted Gacela F1 plants. The peroxidase activity was reduced under salinity, especially in plants grafted onto Atlante while plants grafted onto Terrano presented the highest activity. This study shows rootstock-mediated differencial responses in the antioxidative metabolism of salinized pepper plants that could help to explain the contrasting growth and yield effects observed

Physiological behavior of pepper rootstocks versus nematodes

[SPA] Un desafío de manejo en los sistemas de alta producción son las enfermedades transmitidas por patógenos de suelo, como los nematodos, siendo el injerto con porta-injertos resistentes una propuesta para mitigar estos problemas. Se han realizado pocos estudios en pimiento cultivado en invernaderos bajo condiciones de clima mediterráneo. Por tanto, estudiamos una variedad susceptible (Gacela) injertada en porta-injertos resistentes (C19, C25 y RT17), y la comparamos con plantas no injertadas y autoinjertadas (GAL). Después de la inoculación en los portainjertos susceptibles, la fotosíntesis de la hoja se vio afectada por una modificación en la regulación estomática y en la eficiencia fotoquímica, lo que condujo a desequilibrios en la concentración de nutrientes y a una mejor asignación del carbono de la fotosíntesis para la producción de compuestos bioquímicos de defensa. Estos resultados proporcionan nuevas ideas en los rasgos que pueden identificar portainjertos resistentes a nematodos y, por lo tanto, nuevas herramientas para inducir resistencia, mientras evitamos el uso de desinfectantes en el suelo. [ENG] A management challenge in high production systems are diseases transmitted by soil pathogens, such as nematodes, being the grafting with rootstocks with nematode resistance genes a proposal to mitigate these problems. Few studies have been carried out on greenhouses grown peppers under Mediterranean climate conditions. Therefore, we studied a susceptible variety (Gacela) grafted on resistant rootstocks (C19, C25 and RT17), and compared it with non-grafted and self-grafted plants. After inoculation into susceptible rootstocks, leaf photosynthesis was affected by a change in stomatal regulation and photochemical efficiency, leading to imbalances in nutrient concentration and better photosynthesis carbon allocation for the production of biochemical defense compounds. These results identified new ideas in traits that can identify nematode-resistant rootstocks and, therefore, new tools to induce resistance, while avoiding the use of disinfectants in the soil.Futuros estudios deben analizar el deterioro producido por M. incognita en la regulación estomática y en la eficiencia del PSII, ya que ambos reducen la tasa de fotosíntesis y, en consecuencia, el crecimiento y rendimiento de las plantas

Grafting of sweet pepper against to Meloidogyne incognita infestation: Physiological response

[SPA] Meloidogyne incognita es uno de los principales patógenos del pimiento. La limitación del uso de fumigantes químicos, ha conllevado al uso de porta-injertos con genes de resistencia al nematodo como eficaz alternativa a su control. La reiteración del cultivo de algunos de éstos porta-injertos, provoca la aparición de poblaciones virulentas. La evaluación sobre las características fisiológicas y agronómicas de plantas injertadas sobre Atlante (Me3), C19 (Me3 en diferente background) y Robusto (Me1) frente a una población virulenta al gen Me3, muestra que el injerto sobre Robusto y C19 con genes de resistencia Me1 y Me3 respectivamente a M. incognita, mejoran la respuesta fisiológica y agronómica frente al estrés biótico provocado por el nematodo. [ENG] Meloidogyne incognita is one of the main pathogens of pepper. Limiting the use of chemical fumigants, it has led to the use of rootstocks with nematode resistance genes as an effective alternative to control. The reiteration of some of these cultivation of rootstocks, causes the appearance of virulent populations. The evaluation of the physiological and agronomic characteristics of plants grafted on Atlante (Me3), C19 (Me3 in different background) and Robusto (Me1) against a virulent to Me3 gene population, shows that the graft on Robust and C19 with resistance genes Me 1 and Me 3 respectively M. incognita, improve the physiological response and agronomic against biotic stress caused by the nematode.Al proyecto de investigación FEDER PO 07-41, que está cofinanciado en un 80% por el Fondo Europeo de Desarrollo Regional

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results