- The effect of pressure trunk injections of K₂HPO₄, and K₂SO₄.
solutions on the mineral content, growth, yield and fruit quality of
sweet cherry and mineral content of prune were investigated. A
complimentary study presented in Appendix 1, was conducted to
evaluate the short term effectiveness of K soil amendments, mulching
and foliar K sprays for correcting K deficiency in sweet cherry and
Potassium solutions were injected into sweet cherry trees at an
average rate of 0.4 liter/min and into prune trees at an average rate
of 0.06-0.08 liter/min using a pressure of 3.5-3.9 kg/cm².
Fall trunk injections of 200 g K in K₂SO₄, solution or up to
300 g K in K₂HPO₄ solution had no effect on sweet cherry midshoot leaf
K the following August. Fall prune tree injections of up to 50 g K in
K₂HPO₄, solution had no effect on midshoot leaf K the following August.
One year, fall K₂HPO₄, (200 g K, 79.2 g P) injections of sweet cherry
trees significantly increased the K content of spur tissues and the P
content of buds in March and increased the P content of midshoot
leaves in August.
Fruit set was significantly lower on sweet cherry trees injected
with 200 g K (K₂SO₄) and 300 g K (K₂HPO₄). Yield was significantly
lower for all injection treatments but fruit quality was not affected.
Spring trunk injections of 12.5 g K in K₂SO₄ or K₂HPO₄ solution
increased prune leaf K within four days and K levels remained higher
than controls for at least 22 days with K₂SO₄. Leaf P was increased
within four days by K₂HPO₄, injections and remained higher than controls
Spring applications of 11.36 kg K₂SO₄, per tree by banding,
placing in augered holes in the soil or injection into the soil had no
effect on sweet cherry trees within two years but did significantly
increase August midshoot leaf K in prune trees within one growing
season. A heavy compost mulch applied in the fall increased August
leaf K, N and fruit size on sweet cherry trees and August leaf K, N,
Ca, Mn, Fe, Cu and B on prune trees within one growing season. Prune
tree, shoot growth and yield were increased by compost mulch applications
the second growing season.
Trenches with backfill amendments of K₂SO₄, dolomite lime or a
combination of the two had no effect on leaf K of sweet cherry trees
within two growing seasons. Fruit size was reduced by all trenching
treatments except trenching with K₂SO₄. Trenching with K₂SO₄ and
K₂SO₄, plus lime increased August midshoot leaf K on prune trees to
2.06 and 1.94% respectfully within one growing season and trenching
with lime only increased August leaf K the second season to 1.37%.
One percent K solutions of KN0₃ and K₂SO₄ sprayed on trees four
times during the growing season did not affect leaf K levels, of sweet
cherry trees but did significantly increase August leaf K levels of