Rs. Johnson et al., Can we approach complete dependence on foliar-applied urea nitrogen in an early-maturing peach?, J AM S HORT, 126(3), 2001, pp. 364-370
Citations number
42
Categorie Soggetti
Plant Sciences
Journal title
JOURNAL OF THE AMERICAN SOCIETY FOR HORTICULTURAL SCIENCE
The suspected contributory role of soil fertilization to nitrate pollution
of groundwater has encouraged exploration of novel fertilizer management st
rategies. Foliar-applied urea has long been used to supplement soil N appli
cations, but there have been no apparent attempts to replace soil N applica
tions completely in deciduous orchard culture. Two experiments mere conduct
ed to study the effect of foliar-applied low biuret urea on productivity an
d fruit growth of the early maturing peach [Prunus persica L. Batsch(Peach
Group)] cultivar, Early Maycrest. In a 3-year experiment, a total foliar ur
ea regime was compared to an equivalent amount of N applied to the soil. Th
e foliar treatment supplied adequate amounts of N to the various organs of
the tree including the roots, shoots, and fruit buds, but mean fruit weight
s were Io vr;er than in the soil-fertilized treatment. In a a-year experime
nt, a 50 %-50 % combination treatment of soil-applied N in late summer with
foliar-applied N in October, maintained yields and fruit Weight equal to t
he soil-fertilized control. Some soil-applied N appears necessary for optim
um fruit growth. Soil N application may be needed to support root prolifera
tion and associated processes, but we did not determine a threshold amount
of soil-applied N needed. The combination treatment also reduced excessive
vegetative growth which is characteristic of early maturing peach cultivars
. Therefore, this combination treatment offers promise as a viable commerci
al practice for maintaining tree productivity and controlling excessive veg
etative growth in peach trees.