Effects of climate and fertilization strategy on nitrogen balance in an outdoor potted crop of Viburnum tinus L.

Abstract

Little information is currently available on how fertilization management affects leachate composition and the plant nitrogen (N) uptake of crops under Mediterranean climate. The objectives of this study were to determine the effect of different fertilization strategies and doses on the composition of the leachates and the use of N by plants, to establish a N balance for the different fertilization strategies and doses used and to establish a linear regression model to predict N concentration in leachates from an outdoor potted crop of Viburnum tinus L. 'Eve Price'. Two fertilizations strategies, i.e. continuous fertigation (NS) and incorporated controlled-release fertilizer (CRF), were applied to the crop. The treatments were two NS doses (NSA: 57.4 mg NO 3 --N L -1 and NSB: 43.4 mg NO 3 --N L -1 ) and two CRF doses (CRFC: 5 g L -1 and CRFD: 7 g L -1 ). The NO 3 --N concentration in the leachates from the CRF treatments was high in the first weeks of growing (100-300 mg L -1 ). The efficiency of use of N was greater in the NSA treatment (9.2 g g -1 ). When CRFC was applied there was an increased loss of N by leaching (48 % of the total N). The concentration of N in the leachates for both fertilization strategies was found to be correlated with the variables substrate temperature and precipitation. Therefore, these variables must be considered when determining the dose of fertilizer to be added to a crop, especially when CRF are chosen, to avoid high losses of N by leaching.Additional key words: controlled-release fertilizer; fertigation; Mediterranean climate; nitrate pollution; nitrogen efficiency; woody ornamental. ResumenEfectos del clima y de la estrategia de fertilización en el balance de nitrógeno en un cultivo al exterior en contenedor de Viburnum tinus L.Existe poca información sobre el efecto de la estrategia de fertilización en la composición de los lixiviados y la absorción de nitrógeno (N) por un cultivo en clima mediterráneo. Los objetivos de este estudio fueron determinar el efecto de diferentes estrategias de fertilización y dosis en la composición de los lixiviados y en el uso del N por las plantas, establecer un balance de N basado en la estrategia de fertilización y dosis aplicadas y establecer un modelo lineal para predecir la concentración de N en los lixiviados de un cultivo de Viburnum tinus L. `Eve Price´. Se aplicaron al cultivo fertilizantes mediante fertirrigación continua ( ). Las pérdi-das de N por lixiviación aumentaron significativamente al aplicar el tratamiento CRFC (48% del N total). La concentración de N en los lixiviados de todos los tratamientos se correlacionó con las variables temperatura del sustrato y precipitación, por lo que éstas deben ser consideradas para determinar la dosis de fertilizantes a añadir a un cultivo, especialmente cuando se usan CRF, y así evitar elevadas pérdidas de N por lixiviación.

Effect of different fertilization strategies on nitrogen balance in an outdoor potted crop of Osteospermum ecklonis (DC.) Norl. ‘Purple Red’ under Mediterranean climate conditions

“…These prills were ground manually according to Narváez et al (2012). Total N in the solution obtained was determined using the Kjeldahl method and the NO 3 -content was measured using the ion chromatography system described above.…”

“…temperature and precipitation) during the specif ic growing period and the plants' growth rate can also affect the concentration and quantity of nutrients lost through leaching (Seo et al, 2008). A negative correlation was observed between N concentration in leachates and the temperature (T) during the production of woody ornamental plants under fertigation (Narváez et al, 2012 …”

“…Nitrates from fertilizers are the dominant form of nitrogen (N) in leachates from crops (Cabrera, 1997;Fernández-Escobar et al, 2004;Oliet et al, 2004;Narváez et al, 2012). Half of the nutrients and water applied has been described to be lost in potted shrubs production along the Mediterranean coast of Catalonia (Guérin et al, 2001).…”

“…If substrate T is over 21°C, the nutrients can be released more quickly than expected (Du et al, 2008).The longevity of the CRF indicated by the manufacturer could then be considerably reduced as T increases (Huett & Gogel, 2000). A high rate of nutrient release from CRF can promote losses of soluble N by leaching (Million et al, 2010;Narváez et al, 2012). Depending on the fertilization method, variables such as precipitation (PR) and T take on special relevance on the pattern of nutrient leaching when growing potted plants outdoors in areas along the Mediterranean coast, such as Maresme County in Catalonia, which has moderate winter temperatures, very hot and dry summers, and rainy autumns (METEOCAT, 2012).…”

“…Depending on the fertilization method, variables such as precipitation (PR) and T take on special relevance on the pattern of nutrient leaching when growing potted plants outdoors in areas along the Mediterranean coast, such as Maresme County in Catalonia, which has moderate winter temperatures, very hot and dry summers, and rainy autumns (METEOCAT, 2012). T and PR are variables that are often used to predict the concentration of NO 3 -in leachates (Ramos & Martínez-Casanovas, 2010;van der Laan et al, 2010;Narváez et al, 2012).…”