274 research outputs found
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. GarcĂa, and CDTT ââEl Miradorââ for help in growing plants, the Fundacion SĂŠneca de la RegiĂłn 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 âŹ14,864 and âŹ13,326 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 aĂąo 1999 se diseùó un experimento en 8 lisĂmetros de drenaje de 7x7x0,90 m3 bajo invernadero, para estudiar la lixiviaciĂłn de nitratos en un cultivo de pimiento. Desde el aĂąo 1999 hasta 2001 se han ensayado diferentes dosis de abonado mineral nitrogenado y desde el aĂąo 2002 hasta el 2006 diferentes tĂŠcnicas de cultivo (ecolĂłgico, integrado y convencional), que han permitido evaluar las pĂŠrdidas de nitratos en el drenaje y obtener conclusiones sobre la producciĂłn, extrapolables a condiciones similares de suelo de la Comarca del Campo de Cartagena. Teniendo en cuenta los aportes de N del estiĂŠrcol, el suelo y el agua y como resultado del estudio, se concluyĂł que con dosis de 1,5 UF de N mineral por tonelada de producciĂłn prevista (15 g N/m2 ) para una producciĂłn de 10 Tm/Ha (la media en la Comarca), combinado con el aporte de 4 kg de estiĂŠrcol/m2, era suficiente para obtener buenas producciones con menor impacto medioambiental en comparaciĂłn con las que se aplican en la Comarca y que estĂĄn 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 investigaciĂłn ha sido financiada por el INIA y el IMIDA Se agradece su colaboraciĂłn en la cesiĂłn de los terrenos al Centro Integrado de FormaciĂłn y Experiencias Agrarias de Torre-Pacheco (Murcia)
Balance de agua y nitrĂłgeno en un cultivo de pimiento grueso en el Campo de Cartagena
Se diseùó un experimento consistente en la construcciĂłn de 8 lisĂmetros de drenaje
bajo invernadero en TorreâPacheco. En los aĂąos 2003, 2004, 2005 y 2006 se ensayaron
en dicho invernadero tres tĂŠcnicas de cultivo diferentes (TâE:ecolĂłgico, TâI:integrado
y TâC:convencional) en pimiento grueso, que han permitido, contando con la
informaciĂłn obtenida durante cuatro aĂąos sobre abonado nitrogenado y riego,
evaluar las pĂŠrdidas de nitratos en el agua de drenaje.
Los resultados permiten comprobar como es la relaciĂłn entre el nitrĂłgeno aportado
y el lixiviado para los sistemas de cultivo estudiados, corroborando como una mayor
cantidad de abonado se corresponde con una lixiviaciĂłn de nitrĂłgeno mayor, para las
mismas dosis de riego; pero sin perder de vista que en las parcelas testigo, sin
aportaciĂłn de nitrĂłgeno mineral, se han medido considerables lixiviaciones de
nitratos, aunque menores que en las parcelas con abonado mineral.
Durante el desarrollo de esta investigaciĂłn se ha comprobado, ademĂĄs, que una
disminuciĂłn de las dosis de nitrĂłgeno respecto a las normalmente utilizadas en la zona
de estudio produce cosechas similares. La dosis de 15 g N/m2 de abono mineral
(nitrato cĂĄlcico + nitrato potĂĄsico) combinada con el aporte de 4 kg/m2 de estiĂŠrcol
fermentado se ha mostrado como la mĂĄs eficaz en relaciĂłn con la producciĂłn. Todo
ello indica que el tratamiento TâE acompaĂąado de aportes adicionales de nitrĂłgeno
mineral, inferiores a los realizados en los TâI y TâC, constituirĂa una fertilizaciĂłn Ăłptima
que asegurarĂa la producciĂłn y longevidad del cultivo de pimiento.Esta investigaciĂłn ha sido financiada por el INIA
durante los aĂąos 2004, 2005 y 2006 (Proyecto
RTAâ04â035, en colaboraciĂłn con la Comunidad
AutĂłnoma) y el resto de los aĂąos con fondos
propios del IMIDA. Se agradece su colaboraciĂłn
en la cesiĂłn de los terrenos al Centro Integrado de FormaciĂłn y Experiencias Agrarias de Torreâ
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 estĂĄn asociadas a cambios en el metabolismo hormonal en condiciones de estrĂŠs salino. En este estudio, tres parĂĄmetros fundamentales del metabolismo antioxidativo (peroxidaciĂłn lipĂdica, concentraciĂłn 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 afectĂł significativamente ni a la peroxidaciĂłn lipĂdica ni a la concentraciĂłn de fenoles totales. Sin embargo, las plantas injertadas sobre los tres portainjertos comerciales presentaron una reducciĂłn significativa de la peroxidaciĂłn lipĂdica, que amortiguĂł el daĂąo oxidativo provocado por el estrĂŠs 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 estrĂŠs salino que podrĂan 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 desafĂo de manejo en los sistemas de alta producciĂłn son las enfermedades transmitidas por patĂłgenos 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 mediterrĂĄneo. 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). DespuĂŠs de la inoculaciĂłn en los portainjertos susceptibles, la fotosĂntesis de la hoja se vio afectada por una modificaciĂłn en la regulaciĂłn estomĂĄtica y en la eficiencia fotoquĂmica, lo que condujo a desequilibrios en la concentraciĂłn de nutrientes y a una mejor asignaciĂłn del carbono de la fotosĂntesis para la producciĂłn de compuestos bioquĂmicos 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 regulaciĂłn estomĂĄtica y en la eficiencia del PSII, ya que ambos reducen la tasa de fotosĂntesis 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 patĂłgenos del pimiento. La limitaciĂłn del uso de fumigantes quĂmicos, ha conllevado al uso de porta-injertos con genes de resistencia al nematodo como eficaz alternativa a su control. La reiteraciĂłn del cultivo de algunos de ĂŠstos porta-injertos, provoca la apariciĂłn de poblaciones virulentas. La evaluaciĂłn sobre las caracterĂsticas fisiolĂłgicas y agronĂłmicas de plantas injertadas sobre Atlante (Me3), C19 (Me3 en diferente background) y Robusto (Me1) frente a una poblaciĂłn 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 fisiolĂłgica y agronĂłmica frente al estrĂŠs biĂłtico 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 investigaciĂłn FEDER PO 07-41, que estĂĄ 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 âs = 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 fbâ1 of protonâproton 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
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