Differential nitrogen uptake during growth cycle in young 'Rocha' pear trees
2011
Mota, M. | Neto, C.B. | Oliveira, C.M.
New ‘Rocha’ pear plantings involve higher tree densities, the use of fertilization with irrigation and the adoption of soil conservation systems, demanding a rational use of fertilizers. Knowledge about nitrogen (N) uptake patterns by the trees during the growth cycle can help in decisions regarding N formulations, amounts and dates of application, and contribute to more efficient N use. Two-year-old ‘Rocha’ pear trees grown in pots received 2 g N/tree, at dates corresponding to active shoot vegetative growth, shoot growth cessation and beginning of leaf fall, in the form of either NH415NO3 or 15NH4NO3. N was preferentially absorbed as NH4+ in all sampling dates, ranging from 62 to 66% of the total labelled N recovered in the trees. The fertilizer N use efficiency was also higher for ammonium treatment than for nitrate treatment in all sampling dates.
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