Good Fruit Grower

April 15

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It's all about balance. by Geraldine Warner B alancing the crop load is par- t i c u l a r l y i m p o r t a n t w i t h Honeycrisp, which is more susceptible than other apple varieties to problems involving mineral nutrition. The fruit disorder bitter pit, which is associated with low calcium levels, can be a serious problem, especially in young trees, trees with a light crop load, or trees in warm sites, Dr. Lailiang Cheng, horticulturist at Cornell University, New York, reported during a Honeycrisp Fruit School presented by Washington State University in December. On the other hand, when the tree is heavily cropped, the apples don't color up, are smaller, and have lower sugar lev- els. "To grow good quality Honeycrisp, the crop load has to be right," Cheng emphasized. It's a similar situation with nitrogen. In low nitrogen conditions, when the leaf nitrogen content is less than 2 percent, trees are more prone to biennial bearing. Increasing the nitrogen supply improves fruit set, fruit size, and yield, and reduces the biennial bearing tendency. However, it also reduces fruit color, firmness, and storability. "So, the nitrogen supply has to be right in order to balance all these opposite effects," Cheng said. This is why Cheng believes the two key aspects of Honeycrisp nutrition are: —Improving the fruit calcium level to reduce bitter pit; and —Optimizing the tree's nitrogen sta- tus to balance tree vigor, biennial bearing tendency, and fruit quality. Tree roots take up very little calcium between bud break and bloom. After bloom, total calcium uptake increases linearly until harvest. Partitioning of cal- cium between shoots and leaves or fruit is different from other mineral nutrients. Once calcium is taken up by the roots, the partitioning is largely dictated by transpiration. As a result, typically about 85 percent of the calcium in new growth ends up in the foliage and only 13 to 14 percent in fruit. Cheng said that in warm GOOD FRUIT GROWER APRIL 15, 2014 33 Managing Honeycrisp nutrition "All of our wind machines are Orchard-Rite ." "All of our wind machines are Orchard-Rite ® ." —BOB BAILEY Orchard View Farms The Dalles, Oregon )*"()**( &)$*#* ")&&%)$*%'"* %!*( "%!)$*$&)(*#'*#)&**%)$** *#*#&*%!*( "%!)$*(&)*& "(&%') %'"*'")*'#'(&'*)('&)*")*#*$#'$* %!*#&*#& "(&$*#')!*(&*(!*'")*'#*'(&' "($*'()!*(*#*'")*)$$*#&*#'*# &#') '%!*'"#$)*(&)($* '#*'(&'*%$*&)%()* (!*$()$*) ")*$)&% )*)*)' &#* ($ ()*%! ( "%!)*)&% )*%$ &)('* ($ ()*%! ( "%!)*)&% )*%$*( $#%* #(!*") "()*'")*$()*)#) )(&*%!*(!*)(&*#' "% "*()$*%'*)($*'# #*$%!)$$*'#)'")&* ))*)*"()*(*&)(' #&%!*&)('%#!$"% $$++(!) )!())++*#% '#*&$$&' ( )+(!(+(!+)+%' ) +'#*&"%&"*" %$%'++(! ( (++**# '#*&"'&*%*$ +! )+)+%%" ) +'#*&*"'&#"$ Wind Machine Service For your nearest representative: Cascade "I think making foliar applications after harvesting the crop is a great way to increase the trees' nitrogen reserves to strengthen the spurs for next season." —Dr. Lailiang Cheng SOILS & Weed Control

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