~Fertilizers for Nut Trees~—The deep rich alluvial soils of river and creek valleys do not present the same fertilizer problems as light and heavy upland soils. Manure supplemented with superphosphate at the rate of about 20 to 30 pounds to a ton should prove to be a satisfactory fertilizer on depleted soils. It is spread in a circle around the trees extending out about twice the spread of the branches and plowed or harrowed into the soil. A moderate application would range from 8 to 12 tons to the acre.
Leguminous cover crops are particularly valuable for building up the nitrogen and humus content of the soil when plowed under. Their judicious use with non-leguminous cover crops and supplemented with commercial fertilizers to increase the tonnage for plowing under, will usually bring good returns in growth and production.
CARE OF THE PERMANENT PLANTINGS
Since but few diseases and insects attack nut trees in Missouri, very little if any spraying work will be required while the trees are young. As the trees grow older, however, it may be necessary to give pest control more attention. Caterpillars that infest the foliage of the trees in late summer and early fall can usually be destroyed by cutting off the comparatively few branches on which the worms have clustered and burning them. The pest may also be destroyed on high branches by means of torches. If the trees can be sprayed thoroughly, arsenicals and other insecticides used in spraying apple orchards will be found very effective while the worms are small.
As in the care of a young apple or peach orchard, it is important that the young trees for at least the first two or three years be given cultivation and some fertilization on lands of lower fertility if a good growth is not being made. A heavy mulch of straw or litter around the trees may prove very satisfactory.
Moreover, livestock should be kept away from the trees until they are established and the branches of sufficient height to be out of danger of injury. It is a serious mistake to plant or grow from seed small nut trees and leave them unprotected from farm animals. If the land is to be grazed, each tree may be guarded with strong posts and barbed or woven wire spaced about 8 to 10 feet from the trees.
Once the young nut orchard is thoroughly established and growing thriftily, grass may be grown beneath the trees and furnish nearly as much hay or pasture as though the trees were not present. If livestock is allowed to graze in the orchard, which is a questionable practice while the trees are young, the trees should be pruned and trained to fairly high heads.
~Spacing for Nut Trees~—The growing of nut trees for timber alone requires a spacing of about 25 to 35 feet apart with other species of trees common to the area growing up later between the nut trees to facilitate the development of tall clean trunks. Under such conditions nut production is inhibited and harvests may be comparatively small. Nut trees grown mainly for nut production rather than for timber may be planted 60 to 80 feet apart on the square plan.
The Thomas black walnut may bear a few nuts the second year following transplanting. Different varieties and species of grafted walnuts, pecans, and hickories often begin bearing from two to four years after setting. Chestnut seedlings may also bear in the second or third year. Black walnuts from seed sometimes bear a few nuts at 8 to 10 years of age. Profitable bearing, however, may not be expected in the average nut orchard until the trees are at least 10 to 12 years old.