Products of biotechnology offer the greatest potential for growers to achieve minimum inputs and maximum yields by enabling them to better manage the factors that drive input costs up as well as those that limit production.
There are three proven keys to creating a balanced soil for a profitable growing program.
- Life in the soil including the microorganisms in the soil, which is the foundation for the second and third keys;
- Physical which include tillage, planting, crop rotation, irrigation, etc.;
- Chemical which include fertilizers, herbicides, insecticides, etc.
The following are recognized benefits of a healthy, balanced soil:
- More friable soil requiring less energy in cultivation
- Softer top soil causing less stress and damage to sprouting plants
- Faster and more complete seed germination frequently requiring less seed per acre
- Better decomposition of organic matter
- Better soil aeration and release of CO2 produced by microbial action in the soil organic matter
- More efficient use of soil moisture often reducing costs of irrigation
- Greater drought resistance
- More rapid water penetration and less erosion
- More effective use of plant nutrients present in the soil by increasing organic conversion to plant available forms
- Faster, larger, healthier root formations, and better nutrient absorption
- More efficient use of plant nutrients with an increased fertilizer and chemical efficiency
- Release of nutrients that otherwise would not be available to the plant
- Less loss of nutrients by leaching
- Soluble plant available nutrients are held in the root zone
- Yield increases, often 20% or more
- Quality increase by escalating carbohydrates (sugars and starches), oils and proteins
- Often greater resistance to insect and fungus damage due to healthier, less susceptible plants
- Less weeds
- Less toxicity
Soil fertility cannot be reduced to a simple formula of N-P-K. The microbial life in the soil is responsible for reaching and maintaining a complete balance of minerals in the form of plant nutrients, readily available for the plant’s uptake. When there is a true (available) nutrient balance within the soil, the plants are able to feed as fast as their needs require. This reduces the stress that often inhibit the plant’s growth. This balance also cuts the number of days until harvest, improving the quality of yields in the process.
In recent years the breakdown of the structure of the surface layers of soil under continuous cultivation and the paralleling decline in their productivity has been a matter of increasing concern.
This decline in production from soils which require constantly increasing expenditures for tillage and water represents ever greater economic problems for the farmer and the nation. Increased usage of chemical fertilizers and inorganic soil conditioners, while serving other beneficial purposes, has not alleviated the problem of deteriorating soil structures, loss of organic matter, and the wastage of water and fertilizers. In many cases perhaps the chemicals used have aggravated the situation.
A productive soil is characterized not necessarily by the mere presence of large quantities of plant nutrients, but by the rapidity with which the soil microbes make these nutrients available to the higher plants. The processes that take place within the soil are, for the most part, dependent first upon the activities of living organisms; and hence, the existence of higher plants depends on the activities of the soil microbes. Dr. S. A. Waksman stated in 1952, “The humus content, plus active microorganisms, is equivalent to a high degree of fertility.”
Another noted microbiologist, Dr. Stanley E. Wedberg, University of Connecticut, went further in stating, “The fertility of the soil is in direct proportion to the number and activity of soil microorganisms.”
As you can see there is correlation or an association to humus content and high microbial activity in the soil; but, where does the humus come from?
Organic matter is the source of energy and food supply for the soil organisms and microorganisms. As organic matter is returned to the soil, it is digested by the microbes. The resulting cellular material is mixed with the living and dead bodies of bacteria, fungi, actinomycetes and other microscopic forms of life. Also, together with certain excretory materials produced during their life cycles, they form a dynamic, ever-changing, organic material called HUMUS.
HUMUS is the major storehouse of plant nutrients in the soil. It is literally the “fat of the land.”
Soil microorganisms are involved in many beneficial activities in the soil. These are decomposition of crop residues, mineralization of soil organic matter, synthesis of soil organic matter, nitrification, fixation of nitrogen, immobilization of mineral nutrients and formation of organic substances which may be both stimulative and toxic to plant growth, depending upon the concentration. Organic substances formed by microorganisms influence soil structure stabilization, binding particles of soil together to permit better water penetration and reduce erosion.
Many cropping and tillage practices that a farmer uses are effective in crop production because of their influence on microbial activity. For example, when the soil is tilled, aeration may be improved and aeration is favorable for the growth of the nitrogen, sulfur and iron oxidizing organisms. When the soil lacks oxygen, it is unfavorable as an environment for many plants and organisms.
Every practice or management system influences microbial activity, which in turn influences the decomposition of plant residues, the availability of nutrients and the soil structure. These all influence crop growth, and the growth of crops determines the soil cover and the ultimate organic matter. This influences the balance between the various types of microorganisms whose actions play a major role in the carbon, nitrogen and mineral cycles and thus govern to a great extent the fertility of the soil.
Each spoonful of mellow soil contains billions of living microscopic organisms. Multiply this by the number of spoonfuls of soil in an acre and you have figures that are astronomical. In fact, the living bacteria alone in an acre of soil of average fertility would weight as much as a medium size cow.
This seething mass of microorganisms constitutes a crop of three to five tons per acre foot of soil that the farmer sustains beneath the soil surface, in addition to the crop that he grows above the ground. If the crop of microorganisms beneath the surface does not have adequate food, the crop above ground will suffer from competition for mineral nutrients and be more susceptible to disease.
“Microorganisms eat at the first table. They are in contact with almost every particle of soil. Plant roots are not. Without micro-organic life, soil, the dynamic perpetual system that sustains terrestrial life, would become an inert mass incapable of providing food. Microorganisms decompose organic material and release elements and organic food for repeated use,” states Dr. T. M. McCalla, Research Microbiologists, University of Nebraska.
Microorganisms need three things: Air, Water and an Energy Source starting with organic matter. John Box, Extension Agronomist, Texas A & M has written, “Mike,” the microbe is your best friend and may be the most important livestock you produce. Microbes live in the surface layers of soil in fantastic numbers. Since we cannot see them, we often neglect them. Mike and his cousins can perform chemical miracles that man has not yet learned to duplicate. Treat him well and give him the raw material with which to work, and he will keep your soils in top production.”
In addition to a food supply, you can help by preventing soil compaction. Compaction reduces air supplies, limiting the ability of microbes to perform. Compaction has an adverse effect on root development and the soil’s ability to absorb and hold water.
Without active soil microorganisms, man would long ago have been covered up by his own waste or would have had to find a way of putting his refuse on the moon or elsewhere; but, thanks to Mike and his cousins, these waste materials are recycled and made into compounds that can be reused over and over.
How alive is your soil? A good microscope could show you, or you could use a visible friend to tell you…the earthworm. Earthworms are one of the best indicators of a well-balanced soil. If you don’t have them in great numbers, then you can be reasonably sure that all is not as well in your soil as it should be. On the other hand, if they are very numerous you can know that in most years your soil will be most productive.
Jack Denton Scott, writing in the August/September, 1968 National Wildlife says about the earthworm, “As a soil chemist he has few equals. The earthworm churns the earth into rich topsoil by blending in vegetable matter from the surface into the ground below, and by bringing mineral-rich subsoil up where plants can use it. He drags leaves down into his burrow where bacteria can work on them. What he eats emerges in little clumps of dirt called Castings which are extremely rich in plant nutrients.
Passing through the worm’s digestive tract, both alkalis and acids become more neutralized. Earth minerals and chemicals are broken down, enriching the soil with particle nutrients that plants and seedlings can more easily assimilate. Experimenters comparing the top six-inch layer of the soil with the castings contained in a form that plants can use found there are five times as much nitrate, twice as much calcium, two and a half times as much magnesium, seven times as much phosphorous and eleven times more potassium. Subsequently, scientists found that the soils content of actinomycetes organisms that play a significant role in decomposing all organic matter into humus multiply seven times as it passes through the earthworm.
Our amazing friend is as energetic as he is talented. Each mature earthworm casts up about half a pound of humus a year. Since a population of 50,000 earthworms in an acre of normal ground is common (seven million have been found), you can figure conservatively that earthworms are producing twelve and a half tons of topsoil a year in each acre of good garden-type soil.
As our knowledge of the soil microbes grows, we will learn ways of increasing those species which are needed to overcome problems which we have reacted by changing the natural environment, or problems which existed before, but which have grown out of hand, such as the various fungal diseases. Certainly the time is here for a deeper look into our soils and the problems that limit their production.
If you have a problem soil, i.e., hardpans, compacted soils, low water holding capacity, excessive toxic salts, poor water penetration or just low productivity from tied up plant food, then look to Mike and his cousins…they can help. |
