As Animals Judge Your Crops & Feed Values Are Soil Values
IN CALCULATING THE VALUE of fertilizer treatments or of manure spread on the soil, we have been inclined to charge the cost of the application against the first crop following it. Just how many successive crops on the land are benefited by a single fertility treatment and how long it continues to render returns is a question that has often been raised, but not answered specifically.
By comparing the weights of the crop from the soil once fertilized with those from soils not so treated, one commonly finds that crop increases so measured are not carried forward over many years. However — when the crop’s improved feeding values for livestock and the discriminating selections by animals are brought in to evaluate the effects of putting some fertility back on the soil — then, the effects appear to be much more lasting.
The testimony of the dumb beast points out that we have not appreciated the long-time effects given by barnyard manures, fertilizers, green manures and other restorative additions to the soil.
A Missouri Demonstration
For just how many years the cattle can recognize the effects on the hay from fertilizer put on the surface of a meadow was effectively demonstrated by the herds of some 200-300 head of cattle on the farm of E. M. Poirot, Lawrence county, Missouri. In the spring of 1936, he top-dressed a small part of a virgin prairie meadow by drilling fertilizers of various kinds. This was done in the hope of improving the natural grasses and legumes by this simple method. No rates of any one application exceeded 300 pounds per acre. Not more than two treatments were combined.
The haystack (left) containing some hay from fertilized soil mixed through part of it, as the cattle were cutting it in two, to leave one end (stack at the right) made from “unfertilized” hay. After eight years, livestock cleaned up the “fertilized” hay entirely before consuming the other stacks from unfertilized soil.
The soil treatments were mad across one end of the meadow and covered scarcely more than four of the 100 acres in the field. Because lime was so badly needed on his soil, the fertilizer nitrogen was used as calcium cyanamid.
Examinations of the grasses were made during the early summer following the soil treatment. Later in the season the prairie grass was cut for hay. That from the four acres given fertilizer was a part of 25 acres that went into the first stack. Three additional stacks, each of hay from an area of 25 acres without soil treatment, were the balance of the winter hay supply in this field.
In late October, the cattle were turned into this 100-acre field with the four haystacks. They entered from the end opposite the one where the fertilizer treatments were made. Surprisingly, the cattle soon were gathered about the one stack consisting in part of the hay from the fertilized soil area. The other three stacks were disregarded daily, as the cattle went by them — back and forth between this chosen feed and the water and salt in the lot adjoining. This stack of their first choice was consumed before the cattle took the three remaining stacks from soil without treatment.
After 1936 no more fertilizer applications were made. But each year and on through 1943 the hay was made and stacked in the usual manner. Likewise the large herd of cattle was turned in to consume the hay as winter feed. Year after year, they took first this one stack into which there was mixed less than one-fifth of its bulk of hay from soil given fertilizers back in 1936. For eight successive hay crops, the cattle recognized in the hay mixture the effects of the soil treatment on only a small part of it.
Still Strong After Eight Years
During 1943, the eight time of this manifestation of choice by the cattle, their discrimination was particularly keen. In making the hay that year the stack bottom initially laid down was not large enough to include all the hay from the 25 acres which usually went into the first stack. Consequently, after the hay from the treated soil had already been swept in, with considerable from soil given no fertilizer, the stack was extended at one end. Into the extension went the hay that came from untreated land.
When the cattle were turned in that winter they again went to this stack in preference to the other three from soil that had never been fertilized. But they did not take the entire stack. They ate first only that part in which there was mixed the hay from soil fertilized eight years before. They literally cut the stack in two. They left the end made up only of hay from soil never fertilized. Then when this hay was all that remained, the herd no longer crowded about the one stack. In stead, they distributed themselves about the other three stacks are readily as about this remnant.
Dividends Over Long Period
Here was evidence given by the cattle that after eight years there were still in the hay crop some recognizable qualities produced by putting back on the soil some of the fertility that it gives up in crop production. Here the cattle were reporting that, for eight years after one application of small amounts of plant nutrients, there were still returns to be had in better crops, as the animals judge them. The better crops represented better feed consumption and, therefore, doubtlessly better animal gains.
Such discriminations by livestock are pointing out that when we put manures, fertilizers, and other contributions of fertility back into the soil we gather dividends over a much longer period than we have commonly believed.
Recently a farmer friend of mine told me, “I’ve moved to another farm where I get bigger yields in all my feed crops. But even though I shovel much more corn and pitch a lot more hay, I can’t get my calves to market as early. I’m just not growing as much meat per acre.”
This man doesn’t realize that feed bulk is no indication of feed value. Livestock will not gain more on larger rations unless the feed value of any crop is derived from the basic plant food elements found in the soil. The crop must first build up the woody structure that makes up its bulk. Then, if soil conditions are right, the plant will store up a supply of the raw materials of protein, vitamin, and mineral compounds. Thus, whether a crop offers anything more than bulk and fattening power depends on the condition of the soil on which it grew. Live stock may be fed great quantities of feedstuffs produced on poor soils and still fail to gain weight. It is soil that has been guarded against erosion, fertilized properly, and carefully managed, that grows nutritious crops. Such soil will produce crops that give better feeding results and make more meat per acre.