Effectiveness of fall versus spring soil fertilization of field-grown peach trees
2001
Niederholzer, F.J.A. | DeJong, T.M. | Saenz, J.L. | Muraoka, T.T. | Weinbaum, S.A.
Marginally nitrogen (N)-deficient, field-grown peach trees [Prunus persica (L.) Batsch (Peach Group) 'O' Henry'] were used to evaluate seasonal patterns of tree N uptake, vegetative growth, and yield following fall or spring fertilization. Sequential tree excavations and determinations of tree biomass and N contents in Feb. and Aug. allowed estimation of N uptake by fall-fertilized trees between September 1993 and mid-February 1994. Total N uptake (by difference) by spring-fertilized trees as well as additional N uptake by fall-fertilized trees over the spring-summer period was also determined. In fall-fertilized trees, only 24% of tree N accumulation between September 1993 and August 1994 occurred during the fall/dormancy period. Spring- and fall-fertilized trees exhibited comparable vegetative growth, fruit size, and yield despite lower dormant tree N contents and tissue N concentrations in the spring-fertilized trees. Fifty percent of tree leaf N content was available for resorption from leaves for storage in woody tree parts. This amount (N at approximately equal to 30 kg(.)ha-1) was calculated to represent more than 80% of the N storage capacity in perennial tree parts of fertilized peach trees. Our data suggest that leaf N resorption, even without fall soil N application, can provide sufficient N from storage to initiate normal growth until plant-available soil N is accessed in spring.
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