Due to ever increasing human development, deforestation, and unsustainable land use, soil quality has decreased over time. Unfortunately, soil depletion and its negative effects are now a subject that needs to be addressed.
Soil degradation and depletion reduces its ability to meet the needs of future generations.
As soil depletion impacts on nutrition are vast, promoting sustainable land and land management is thus the basis for ensuring a quality food production system. We must take measures to improve our general nutrition quality, living conditions and regain a healthy environment.
What is soil depletion?
Soil depletion refers to removal of nutrients from the soil. Usually, we use this term to refer to changes caused by intensive agricultural use of soil. It also refers to structural changes of soil. Soil depletion also results in loss of biological diversity.
How does soil depletion affect nutrition?
Soil is a non-renewable resource, and its conservation is essential for food safety and our sustainable future. Soil is the ultimate resource for food and heavily affects our nutrition.
It is often neglected. Unfortunately, loss and decay of soil is not reparable within a life of a human. At the same time, its quality is directly related to the quality and quantity of food. Therefore, it directly affects the quality of our nutrition.
Fertile soil encourages the growth of plants by providing nutrients. It acts as a water tank and serves as a foundation for the plant roots. In turn, vegetation, trees and greenery prevent soil decay and depletion. They stabilize it, maintaining the water and nitrogen cycle, as well as cycle of other nutrients. Plants also assist in reducing the negative effects of water and wind erosion.
As we use the soil for intensive agricultural production, we erode the nutrients. This is especially true if the soil is used to produce the very same type of plants, all the time and there is no proper crop rotation.
When new crops cannot extract sufficient nutrients to grow properly, industry and farmers decide to use chemical fertilizers – to improve the soil condition.
Research – The Mayer Study
Experts sometimes refer to the measures we take to improve soil depletion as “nutrient bank accounts”. However, we must be aware of the consequences. It is very interesting to take a closer look at the results of research conducted by Anne-Marie Mayer in the UK in on food nutrient changes between the 1930s and the 1980s.
Mayer compared the nutritive content of twenty different kinds of vegetables and fruit regarding eight essential nutrients with the results from a similar study conducted in 1936. The nutrients list included calcium, iron, sodium, magnesium, potassium, copper, and zinc.
The results were striking. They showed that the levels of calcium, copper, and sodium were significantly decreased in vegetables. Similarly, magnesium, iron, copper, and potassium levels were significantly decreased in the tested fruits.
Scientists concluded that, despite the differences in sampling and testing, the results were accurate enough to prove the devastating impacts of soil depletion on nutritive values of vegetables and fruits.
Research – The David et al Study
Another analysis, done by Davis et al. in 2004, showed that there is a significant difference between nutritive values in fruit and vegetables tested in 1950 and 1999. Their study was focused on carbohydrates, energy, proteins, fats, iron, vitamin A, and riboflavin levels in fruit and vegetables. They also took a closer look at the levels of ascorbic acid, niacin, calcium, and thiamine content in food.
They tested 39 different vegetable species, as well as 2 kinds of fruits.
The greatest drops were found in calcium analysis, with up to a 16 percent reduction. Iron was next, with 15 percent less in 1999. However, this group of authors stated that there are factors other than soil depletion impacting the nutrient content in food, including cultivation methods.
Research – The White & Broadley Study
The hypothesis that soil depletion negatively affects food nutrient composition was further supported by White and Broadley. study from 2005 showed that the difference in nutrients in the foods tested in the USA in 1930 and 2004 and in the UK in 1930 and 1980 is drastic.
The UK results over the 50-year span showed decrease in copper of the amazing 73 percent! Moreover, sodium levels by 50 percent and magnesium levels dropped for 19%.
The USA results over the 90-year span showed a decrease in calcium levels (37%), copper (40%), as well as iron (up to 75%). These were the results of testing on vegetables. Analysis of fruit nutritive content showed that copper levels dropped for 36% and iron the amazing 72%.
These authors took into consideration genetically-based changes. As per the Davis et al study, they also pointed out that soil depletion is not the only cause of such a drastic decrease in nutritive values of fruit and vegetables.
They concluded that their results were worse than those found by the Mayer research because genetically-based changes were not as prominent as today back in 1980s, when the latter study in the UK took place.
Excessive exploitation of agricultural soil has led to increasingly pronounced soil degradation and depletion. Today, we can recognize this as a serious ecological problem. As a result, nutritive values of foods we produce today have drastically changed over the past 50-70 years.
This is why more and more eco-conscious scientists and agriculture experts emphasize the importance of organic farming. The philosophy of organic farming is based on sustainable exploitation of natural resources (mainly soil and water).
It is also based on reducing degradation, environmental pollution, and soil depletion through implementation of natural soil enrichment methods. Such measures will significantly improve the nutrient content of the food we produce and consume.