e not at all. Good results and good
crops may be expected only when several factors are normal and
conditions favorable. After twenty years of keeping records and
observations on nut trees and through correspondence with other growers,
I consider the main reason for crop failure or light production to be
climatic conditions and the weather for an entire year.
The black walnut produces a pistillate flower at the end of the present
season's growth. The staminate flowers, or catkins, come from last
year's wood. Good growing conditions are desirable for wood growth and
fruit bud formation and any retarding of growth the previous season
means little or no production. Winter injury to wood and bud, diseases
or insects attacking the foliage, soil moisture, and summer temperatures
will lower tree vitality. There are times when strong vigorous trees
fail to fruit which could be due to a high or low carbohydrate-nitrogen
balance. Soil type, plant food, age of tree, and location will have some
influence on annual or even biennial production but yet are not the all
important reasons for light crops.
The pollen of the black walnut is mostly wind borne as few insects ever
visit the flowers and pollination is dependent on wind borne pollen.
Trees planted in groups and close together are generally more productive
than trees planted in orchard rows even as close as 40' by 40'. When the
weather is cold and rainy during bloom, one should not expect much of a
crop.
The staminate flowers opened early in Indiana the years of 1950, 1951,
and 1952. The weather was more or less ideal during the time the catkins
had elongated and about ready to shed pollen. This warm spell was
followed by a fairly cool weather and considerable rain, which delayed
the opening of the pistillate flowers, consequently the pollen dried and
was lost before the pistil was receptive.
The few walnut trees in the University plantation have always had the
best of care. The trees have been mulched, fertilized (both through root
and leaf feedings), sprayed, cultivated and seeded to grass with the
grass clipped. The trees are some distance away from other seedling
walnuts and a bit off the beaten path of the right direction of the
spring winds. The varieties are Ohio, Stambaugh, Stabler, Rohwer, and
Thomas. When the spring weather is balmy at flowering time, the trees
bear a respectable crop but let the weather change to cool and moist and
then that is the time one be
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