Soil Formation

Early scientists, beginning with the Great Russian soil scientist Dokuchaev in about 1885, recognized soil as a product of the environment. The action of decay and biological activity on surface of the Earth eventually led to the formation of a soil. The kind of soil that developed is thought to be the result of six natural factors acting together: parent material, climate, vegetation, topography, time and man. In many instances only one or two factors dominate allowing us to understand and classify soils more easily.  I would like to share how each of these factors affect the formation of soil.

Parent material refers to the material, which has undergone decay to produce the soil present today.  Soil parent material may be rock that has decomposed in place, or material that has been deposited by wind, water, or ice. The character and chemical composition of the parent material plays an important role in the determination of soil properties, especially during the early stages of development.  Through the decay process, parent material is broken down, moved, sorted and deposited. The type of soil that has developed is, in large part, determined by the origin and type of parent material.

Parent material composition has a direct impact on soil chemistry and fertility. Parent materials rich in calcium, magnesium, potassium, and sodium, are easily dissolved in water and available for plants.  Limestone and some lava have a high content of soluble nutrients and produce fertile soil in humid climates.  Soils developed over sandstone are low in soluble nutrients and coarse in texture (sandy), which facilitates leaching. Parent material influence on soil properties tends to decrease with time and climate becomes more important.

The nature of the underlying parent material, influences many physical properties of the developed soil.  The form of the landscape is often a clue as to the type of soil parent material. A rolling landscape with eroded knolls and a stony surface is typical of glacial till deposits. Flatter landscapes with few stones are typical of river or water deposits. Can you guess what kind of parent material is in your area?

The climatic characteristics, which have the greatest influence on soil formation, include temperature, precipitation and wind.  Temperature – effects the of decay process and hence soil development may be increased with warmer temperatures and higher moisture levels. These conditions enhance chemical reactions. Conversely, cooler temperatures and lower moisture amounts would slow down the effects of soil development.  Highly developed soils (or older soils) tend to be less productive and are found in the tropical regions.  If you were to look at most productive soil they are far north or south of the equator.

Soils are in some respects just like us, they start off young and they eventually get older.  Older soils, which are found in warm tropical areas, are less productive.  I know the older I get the less productive I sometimes feel.  In the Bible it tells us about how God created the entire world and when it came time for God to create mankind the Bible says, “the Lord God formed man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being.”  When we die we once again return to the soil.  But what should our goals be during life?

Do you have one single goal in life that consumes you, something that has become the primary force that stimulates and motivates you daily in everything that you do? Or do you feel like someone in a boat whose objective seems to change with the various hazards he finds around every bend in the raging river as he is being propelled along trying to navigate white water, logs, and rocks. Life can be like that. If we are not careful, our goals and objectives are set for us by the demands of the everyday forces of life.

Goals and objectives are tremendously important because they are dynamic and determinative of what we do with the life God has given us. It has been said, “Aim at nothing and you will hit it every time,” and “People don’t plan to fail, they just fail to plan.”  Again, let me ask the question, if you could reduce your life to one primary goal, what would it be? On a day-to-day basis, what are you actually focused on and seeking to accomplish?  Think about what was on your mind every morning this week when you woke. 

God doesn’t expect us to be oblivious to the problems and needs of life, but when our goals are God’s goals we are better able to look through our problems to the Lord. When our focus is the Lord, something wonderful begins to happen in us: God begins to change us and make us like His Son.

One of the consequences of having God’s purpose is a life of peace even in the midst of trials. To prepare His disciples for His departure and absence, the Lord instructed them concerning their purpose in the world. In the midst of this instruction, just a few hours before the Lord Jesus went to the cross to die that we might have peace with God and know the peace of God, He made this very illuminating statement: “Peace I leave with you; My peace I give to you; not as the world gives, do I give to you. Let not your heart be troubled, nor let it be fearful” (John 14:27).

Many Christians, however, seem to have little joy or peace. One of the reasons is found in the Lord’s statement regarding peace. We too often seek our joy and peace from that which the world gives rather than from the Savior who provides peace and joy in a very different way and from a very different source.

Our goals not only say a great deal about us but they also, from a Christian perspective, have everything to do with spiritual change and with our experience of joy, peace, and other Christ like qualities. Lying close to the bottom of all we say and do are our basic aims, whether we are seeking to protect ourselves, meet our perceived needs or desired pleasures, or whether we are seeking to protect someone else. The point is simply that goals are dynamic and determinative. They will strongly affect how we live.

The only adequate goal for the Christian is knowing Christ (Phil. 3:8-10) and Christ like transformation (Phil 3:11-14). This means pursuing Christ, which will result in growth in the experience of the character of Christ—his love, grace, mercy, endurance, values, priorities, pursuits, etc.

The need for growth and maturity or spiritual transformation is in essence a call to holiness. This is a call to wholeness as believers become more and more set apart to God and experience His life in theirs through the work and ministry of the Spirit of God. The Word from the Bible is our foundation and the light that illuminates our path.  There is a great verse I want to share with you:

1 Peter 1:14-16 As obedient children, do not be conformed to the former lusts which were yours in your ignorance, but like the Holy One who called you, be holy yourselves also in all your behavior; because it is written, “You shall be holy, for I am holy.”

Did you know that for every increase in 10 degrees Celsius that chemical reactions double.  That is why the soils in warmer moister climates tend to be so much older.  Temperature and precipitation strongly influence physical and chemical reactions on parent material. Climate also determines vegetation cover, which in turn influences soil development. Precipitation also affects development factors like the movement of dissolved nutrients through the soil. As time passes, climate tends to be a prime influence on soil properties while the influence of parent material is less.

Climate affects both vegetative production and activity of organisms. Hot, dry desert regions have sparse vegetation and hence little incorporated organic material in the soil.  Bacterial activity in cold regions also inhibits the breakdown of vegetative matter causing it to build up. In the warm and wet tropics, bacterial activity proceeds at a rapid rate, thoroughly decomposing leaf litter to the point where the soils lack organic matter.

Climate, interacting with vegetation, also affects soil chemistry. Pine forests tend to dominate cool, humid climates. Decomposing pine needles in the presence of water creates a weak acid that strips soluble bases from the soil leaving the soil in an acidic state.         

Vegetation is very important in soil formation from five main aspects. 

Topography can have a significant impact on soil formation. Topography influences the runoff of water, and its orientation affects microclimate, which in turn affects vegetation.

Let me first tell you how topography can effect soil erosion.  First, the slope of the land affects the degree of runoff that is generated when rain falls to the surface. Picture in your mind a mountain.  The mountain slope you are imagining receives the same amount of precipitation. As the water starts to run down slope, the water that has accumulated near the top of the mountain it runs off to lower portions of the mountain.  As a result the runoff water is increasing as you move down slope. This is because the amount water in any one portion of the mountain is the same, but what runs into it from an upslope increases as you move down slope. Additionally, as the water runs down slope its speed is increasing. As a result, the rate of erosion is increasing as you near the base of the mountain. Erosion causes a stripping of the soil thus preventing it from developing.

Let’s continue to follow this water and eroded soil as is leaves the mountain and flows into a stream where it’s speed starts to decrease.  The largest size particles, like sand, are the first to settle out of suspension.  Fine, clay size particles can be carried further away from the base of the slope before they are deposited. As a result, sandy soils tend to be found near the base of the mountain and fine textured soils are located further away.

Hill slope orientation affects the microclimate of a place. As the inclination of the surface increases, so does the local sun angle. As the local sun angle increases, the intensity of heating increases causing warmer surface temperatures and likely, increased evaporation. Orientation of the hill slope is certainly important too. Those slopes, which face into the sun, receive more warming than those facing away. Thus inclined surfaces facing into the sun tend to be warmer and drier, than flatter surfaces. The microclimate also impact vegetation type.

The last, but one of the crucial factors in formation of soil is time.  Did you know that it takes up to 100 years for 3 cm of soil to form?  Therefore, it takes a great deal of time for all of the soil forming factors to work together to form the soil you are now farming.

The early scientists did not include man in the soil forming factors.  Today we realize that man can profoundly affect soil development in both negative and positive ways. By good management, man can maintain or improve the soil. On the other hand man's profit motivation or lack of understanding can undo thousands of years of God’s handiwork.