Mankind has harbored an age-old grudge against insects and fungi, so that under the heading of crop protection from these pests there has developed a large insecticide and fungicide industry.
Relatively little attention has been paid to the effects of a nutritional character that can be obtained from simultaneous applications of essential elements. Insects will probably always constitute a problem of destruction, either of them or by them. But fungi, bacteriae, viruses, can be made to combat, control and balance each other; depending on the conditions under which their propagation is either facilitated or inhibited.
There is evidence that so-called essential nutrients, also variously referred to as "minor", "trace", "rare", or "micro" elements play a direct as well as indirect role of considerable importance in this matter, and that trees can be fertilized, sprayed, injected or treated with them in other ways to insure their growth, health, crop bearing ability, longevity, disease—frost—and drought—resistance. There still exists a paucity of scientific explanations on these subjects, but there is already a good deal of scattered information, which it is my purpose to draw to your attention. People do not care about scientific facts if they can obtain results without them, and then scientific concepts too may undergo changes. The manner in which trees obtain their nutrients from soil, air and water, however, will forever remain unchanged, whether we understand it or not, and it behooves every grower to observe effects from causes, and to reflect upon them, and report his observations to his association for the benefit of all.
Physical Soil Characteristics
That the primary requisites for tree growing are the physical characteristics of all soils favorable for that purpose requires no discussion. The successful nut tree planting starts with the soil, whether it be on the scale of an orchard, grove, or just a few trees around the farm or garden.
The better soils for general crop production are on limestone, basalt, dolemite, dolerite, diorite and gabbro formations, whereas sandstones, aplites, granites, pierre shale, cretacious rocks and volcanic formations weather into inferior soils. Gneiss can be sometimes good, sometimes unfavorable for building of fertile soil.
It is well to bear in mind that geology and botany are our two fundamental sciences, and that all our other sciences are in reality departments of these. Chemistry can be either a branch of botany if it deals with organic chemistry, or else a branch of geology, if it deals with inorganic chemistry, and it would appear that the modern scientific grower of nut trees or any other crops is wittingly or unwittingly concerned with both. Biology and zoology both are branches of botany.
The Essential Elements
In the past, economics have governed any crop production, whether of trees, grains, fruits or vegetables; not nutrition and health. The future in all likelihood will demand improved crops from the standpoint of nutritional purposes as foods. It is gradually being realized that the production of better crops can be brought about by greater application of essential nutrients to soils or as nutritional sprays direct to trees, and that such practices also reflect true economics. The same principle should govern wood production.
According to our today's knowledge, there are at least nineteen elements invariably essential to life, viz: