THE PRINCIPLES AND CHARACTERISTICS OF THE MAINTENANCE OR PROLONGING OF SOILS

In considering the principles and characteristics of the maintenance or prolonging of soils, we must first look at some the features of good and quality soil. A well trained and experienced farmer will tell you that a good and quality soil should be a soil that can;

1. Drains well and warms up quickly
2. Does not crust after planting
3. Soaks up heavy rains with little runoff
4. Stores moisture for drought periods
5. Have few clods and no hardpan
6. Resists erosion and nutrient loss
7. Supports high populations of soil organisms
8. Does not require increasing fertilizer for high yields
9. Has rich, earthy smell
10. Produces healthy, high quality crops

All the criteria mentioned above indicate that the soil functions effectively and will continue to produce long into the future during cultivation. Creating soils with these characteristics can be accomplished by utilizing soil management practices that optimize the processes that are found in soils that give room for natural growth.

Most question people asked are; how does soil in its natural condition function? How do forests and natural grasslands produce plants and animals in the complete absence of fertilizer and tillage? What are the basic principles by which these soils function? The answers to all of these questions assure that the soil will be a productive as well as profitable now and for future generations during farm practices. One good thing that can happen is when the soil's natural productivity is managed in a sustainable manner; the reliance on purchased inputs declines, while land value and income generation increases on a yearly base. Some of the things we spend money on in other for them to be productive and profitable can be done by the natural process itself for little or nothing in cost.

Soil texture and its structure

Soils consist categorically of four components which include minerals, air, water, and organic matter. In most soils, the minerals represent about 45% of the total volume that is present, water and air about 25% each, while organic matter from 2% to 5%. The mineral portion in the soil consists of three distinct particle sizes that are classified as sand, silt or clay. Sand is the largest size particle in the classification that can be considered as soil. Sand is largely the mineral quartz, though other minerals are also present. Since quartz contains no plant nutrients, sand is then the lowest contributor to soil fertility of the three soil particle sizes. However, sand cannot hold nutrients; they leach out easily with rainfall. That is why sandy soils are not as productive as loams and need to be spoon-fed with fertilizer. Silt particles are much smaller than sand but are like sand, silt is mostly quartz in nature.

In considering soil particles, the smallest of them all is clay. Clays are quite different from sand or silt in their nature and they also contain appreciable amounts of plant nutrients. Clay has a very large surface area resulting from the plate-like shape of the individual particles. The textural designation of a soil is derived from the relative portions of sand, silt, and clay. A sandy loam, for instance, has much more sand and much less clay than that of a clay loam. A loam soil is a mixture of sand, silt and clay. Most soils are some type of loam in nature. They are more accurately described by the words the preface the word loam, such as: sandy loam or clay loam.

Structure refers to the combination or aggregation of sand, silt and clay particles into larger secondary clusters. If you grab a handful of soil, good structure is apparent when the sand, silt, and clay particles are aggregated into granules or crumbs. Both texture and structure determine pore space for air and water circulation, erosion resistance, looseness, ease of soil tillage, and root penetration in the soil. However, while texture is an innate property of the native soil and does not change with agricultural activities, structure can be improved or destroyed readily through our choice and timing of farm practices in use.

The importance of organisms to the soil

Mere looking at a landscape you might be wondering how native prairies and forests function in the complete absence of tillage and fertilizers? These soils are simply tilled by soil organisms, not by mechanical means. They are fertilized too, but the fertility is used again and again and never leaves the site. Natural soils are covered with a layer of plant litter and growing plants throughout the year. Beneath the surface litter layer, a rich complexity of soil organisms decompose plant residue and dead roots, then release their stored nutrients slowly over time. Topsoil is the most biologically diverse part of the earth. Soil-dwelling organisms release bound-up minerals that convert them into plant-available forms that are then taken up by the plants which are growing on the site. The organisms recycle nutrients again and again from the death and decay of each new generation of plants growing on the site.

In the soil, there are many different types of creatures that live on or in it. Each has a role to play. These organisms will work for the farmer's benefit if they are simply managed for their survival. Consequently we may call them as soil livestock. While there are a great variety of organisms that contribute to soil fertility, the organisms are earthworms, arthropods, and the various microorganisms merit particular attentions which are also present.