permaculture

[Stephen Sherman <spsherm@msn.com>]

Thanks for the advise, and here are some more details...

I am in Colorado in the mountains at ~8300' elevation. Orchard is on a 
slope with ESE exposure. Soil is a sandy loam. Rather low in P, good to 
a bit high in K and low in N (also some trace deficiencies in B, Mn and 
S according to soil tests). We tend to have dry climate (~20" precip per 
year) and I irrigate as needed, including in winter when the soil is not 
frozen. It can be quite windy here (winds up to 80-90mph are a common 
thing).

I have been on a program to improve the soil in the orchard. Fall 
application of composed manure (can't use in spring/summer as it 
releases N way too late in the growing season here).  I also have been 
using some conventional fertilizers mostly for building P, but they come 
with N most often (MAP and DAP). I'd love to use soft rock phosphate, 
but using that for large areas is cost prohibitive, unfortunately. I 
don't think the N application last spring (all before bud break) was 
excessive, at least for a normal fall; just that it contributed to late 
growth and a lack of hardening off in combination with the weather and 
deer damage. However I am cutting back on the soil program for a variety 
of reasons, the apple trees among them.

The trees which died outright were primarily cherries, peach and pear. 
All of those are marginal here and perhaps last winter was a wake-up 
call for me to not waste time on trees that will die within a few years 
even if they do well at first. Most of the apple tree damage looks like 
winter kill. On some there is the obvious bark discoloration and bark 
splitting. No doubt due to lack of hardening off in time for the cold 
snap, and our bright sunny and cold winter days. I use spiral trunk 
protectors and tree wrap, and for the most part the areas covered by 
those made it through OK; although there was some splitting under the 
protectors on two trees. I am considering painting the trunks and lower 
branches with  diluted latex paint for this coming winter as that should 
help.

Some of the trees did not show any bark discoloration or splitting, but 
the bark on the upper part of the tree just dried up. That is got 
wrinkled and dry looking. A cut and lift of a small bit early in spring 
showed no green cambium in these cases. This may be due to dehydration 
over the winter. It was especially cold and windy last winter, but there 
was lots of moisture (in the form of snow), so much that I could not do 
my usual winter irrigation as the ground was snow covered and frozen 
from Dec til April. Perhaps due in part to the lack of proper hardening 
off in the fall? Again all of these trees had made it through several 
previous winters here without issues.

 I was thinking that foliar feeding with a P and K base plus kelp might 
help. At least for the trees which are not exhibiting good growth from 
the  parts which are growing. But I was a bit concerned that putting on 
an imbalanced fert might cause more issues.