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Simulation of nitrogen dynamics in an alluvial sandy soil with drip fertigation of apple trees
Author(s) -
Riga P.,
Charpentier S.
Publication year - 1999
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.1999.tb00061.x
Subject(s) - fertigation , leaching (pedology) , orchard , environmental science , nitrogen , dns root zone , denitrification , fertilizer , soil water , alluvium , agronomy , soil horizon , hydrology (agriculture) , shoot , silt , chemistry , soil science , geology , biology , paleontology , geotechnical engineering , organic chemistry , geomorphology
. In order to optimize the management of the N‐fertilizer inputs with drip fertigation on sandy‐silt soil under apple tree orchard cultivation, we observed in situ: (i) the N and water soil transfers, (ii) the N levels in all leaves, fruits and annual shoots, and (iii) the root distribution. Then we used a mechanistic one‐dimensional model (WAVE, Vanclooster et al. , 1994) to quantify the annual parameters of the water and nitrogen balance on a daily basis. The horizontal heterogeneity along the row of the tree‐soil‐dripper system has been treated with two adjacent compartments: one under the dripper and receiving fertigation and the other outside this zone. N transfers in the tree make it impossible to estimate directly N uptake by roots over time. The simulated N losses were due to equal amounts of N leaching below 0.9 m deep (9 g N tree −1 year −1 and denitrification (7 g N tree −1 year −1 . The simulated losses of gaseous N were localized predominantly in the compartment under the dripper and showed a higher rate of leaching during the period of N input when the wet conditions and the high NO 3 − concentrations were favourable to denitrification. The N‐leaching at 0.9 m depth was greatest outside the growing season and was caused by the extension of the N‐inputs after the harvest date. This practice, based on the objective to store nitrogen before the period of dormancy does not seem to be justified.