The Use of Fertilizer in a Walnut Orchard

By L. K. Hostetter, Pennsylvania

Sometime in the fall of 1941 Professor Fagan of Pennsylvania State College, and Mr. Graham of Cornell University, called on me and proposed to make some fertilizer tests in my walnut orchard. The following spring Professor Fagan sent me 16 bags of fertilizer, one bag for each tree.

These tests were divided into three parts and each part had one tree that received nitrogen, superphosphate and potash, one that received nitrogen and superphosphate, one nitrogen and potash, one superphosphate only and one potash only and a sixth tree that received no fertilizer.

In the first group all the trees received a liberal amount of mulch. In the second group they received no mulch but the same fertilizer as the first group and in the third group they received the same fertilizer, no mulch but raw lime was added to the fertilizer. One tree received lime only.

There was a heavy sod in the part of the field where these tests were to be made. This sod was torn up with a springtooth harrow (weed hog) about March 15th and the fertilizer was applied on May 6th.

That year was a very poor one in which to make these tests, for during all of July and August we had continuous rainy and cloudy weather and by the first of September all of the leaves had turned yellow and dropped.

Most of the trees had a big crop of walnuts which were gathered about October 10th, the nuts from each tree being kept separate. After they were cracked the kernels were weighed and graded and believe it or not, the tree that received lime only had the best grade of kernels, and second best were one that received lime and potash and another lime, nitrogen and potash. The tree that received mulch and potash also had a very good grade of kernels.

In 1943 the same tests were repeated. This was again a poor year for we had very little rain during all of August and September just when the trees needed it most. The tree that received nothing had the best quality of kernels and again all the trees that received potash had good kernels.

In 1941 I grew two acres of tobacco and the following spring the stalks were cut in one-inch pieces and put on about twenty-five trees. The first year I could not see that it did any good but this past summer all the kernels from these trees were just perfect. It surely is a pleasure to crack walnuts when at least 98% of the kernels are perfect.