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

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 - -NL -1 and NSB: 43.4 mg NO 3 - -NL -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.