Soil degradation sounds dramatic, and for good reason: it is what happens when human activity affects the soil quality in such a way that productivity declines in a temporary - or even a long-term - way. Land degradation is such a big deal it was defined and is being monitored by the United Nations Environment Programme. As world populations grow, food security becomes a bigger and bigger issue, and soil fertility is as important as water and weather to ensure adequate crop production.
Contamination and soil erosion are the first things that come to mind when you think about soil damage, but there are other forms of soil degradation you may not have thought about, like soil compaction. Let’s review the most common causes of soil degradation, and learn about their remediation and prevention.
The topsoil is the layer of soil with the highest concentration of organic matter, and therefore the one best suited for plants to grow and thrive. Erosion is what happens when the topsoil wears away, and all that rich, organic matter is gone from the soil and no longer available for plants to grow. Water and wind erosion are the biggest causes of erosion, but in many cases, they are worsened by human activity: deforestation, bad farming practices, insufficient drainage can all increase erosion and significantly decrease the productivity of agricultural lands.
If you want a deeper dive into the causes and solutions of erosion, read our article about soil erosion. **link to soil erosion blog**
The very agricultural equipment that you use to increase your productivity may be damaging your soils and affecting the future fertility of your fields. Farm machinery is bigger than it ever was, and the weight of 5 and 10-ton trucks damage the soil structure, driving soil particles together until they harden into a compact mass that cannot be penetrated by roots and that does not let water percolate properly. This is called soil compaction, and you should be keeping an eye on it to make sure your harvests don’t dwindle.
There are different causes and solutions for soil compaction - read more about them, as well as on how to diagnose it, in our blog.
Contamination of both soil and water sources is one of the greatest problems faced by our generation, and they affect agriculture fields in the most direct way. Contaminated soil can affect plants directly, making them sick or weak. It could also not affect them directly, but be absorbed and accumulated in plant tissues, which will then become contaminated and decrease the value of your harvest. Contamination in the soil also tends to hurt the soil biota, and all those organisms living in the soil are vital for healthy soil and healthy crops.
There is hope: bioremediation refers to many clean, natural ways to deal with soil contamination. Find out what it means and how it can help you in our blog about bioremediation.
Poor soils can only offer so much to the plants growing in them, and soils have been becoming steadily impoverished during the last decade. Experts agree that intensively farmed soils that don’t have a vegetative cover are at risk of losing nutrients. This is aggravated by the use of high yielding crop varieties, which take a lot out of the soil, paired with relatively poor fertilizers that do not restore enough nutrients back to the soil. This chronic cycle of over planting and under fertilizing leads to loss of soil quality and diminished productivity.
If the water you use on your fields has high salinity (meaning it has a lot of salts dissolved in it) the salts will start to accumulate in the soil, giving you what is known as sodic soil, saline soil, or a mix of both. Soils with high salinity or sodicity are generally very bad for plants since they significantly reduce the root’s ability to absorb water. High salinity in the soil will also hinder germination and stunt plant growth. Test your soils and work to fix any salinity issues you may have, to increase yields and germination ratios.
Acidic or “sour” soils are not necessarily a bad thing, depending on what you are trying to grow. But in general terms, if the pH of the soil is less than 7 your soil is acidic by definition, and if it’s less than 5.5 it is seriously acidic, and only certain plants will thrive in it, such as azaleas, blueberries, and conifers. There are several ways to amend your high acidity soils, so don’t despair.
If your soil has very little water holding capacity, and you find your plants looking thirsty even after watering, it’s safe to say you have dry soil, with a high content of sand or other coarse aggregate that allows water to filter through freely. This is a good thing for many kinds of crops, but not all. If you wish your soils would hold water better, there are many solutions, and we will be happy to tell you more about them.
Too little sand and too much clay may cause the opposite problem: a soil that does not drain well but tends to hold on to water instead. A bad case of wet soil can kill plants if they are susceptible to root rot and fungal disease. Compaction in the subsoil levels may also lead to wet soils since it does not allow the water to continue percolating but keeps it above a certain depth. Different causes for wet soils require different treatments, but in most cases, it is not very difficult to amend your soils and get them in top shape.
You fertilize your crops to get a good harvest, but remember to go beyond the needs of the plants, and leave something for the soil too. High-yield crops have high demands, and if your fertilizer is insufficient, the plants will start depleting the soil.
Sometimes the soil is only lacking one nutrient or two, and in that case, it is easy to add just what’s missing, be it nitrogen, calcium or something else. Testing your soils will give you valuable information regarding what your soil - and your plants - need to thrive.
Compost is the cure to many soil problems. Soil too wet? Mix in some compost to improve drainage. Soil too dry? Compost will help retain moisture. Compacted soil? Work some compost in and let those good microorganisms do their work. Rich, mature compost brings many elements that help restore the soil’s balance and reactivate its life - add it to your soil at least once or twice a year.
If you are having erosion issues, mulch is your best friend. It can also help to prevent surface compaction and alleviate dry soil problems. Mulch protects the soil in several ways and helps retain water and nutrients that would otherwise be carried away by the rain, wind, or sun. One added advantage of mulch: it helps control weeds!
Worms and other living creatures in the soil can be very beneficial to maintaining the soil’s balance and ensuring productive plants. Their contributions to a good soil include keeping it porous and loose, improving air and water circulation, digesting larger particles of organic matter and turning them into worm castings, which are easier to consume by plant roots.
Animal-based soil amendments include manure, bat guano, bone meal and any other such animal byproduct used to enrich soil. On the good side, they improve soil structure, bring many nutrients, and enhance the soil biota. On the negative side, they may also bring undesired microorganisms into the soil. Use cautiously, and apply at least 2 weeks before planting, to give them time to settle.
Plant-based compost, grass clippings, wood chips, kelp, seaweed extracts, and the like fall under the category of plant-based soil amendments. They do wonders for soil structure and help regulate the soil’s moisture levels. Make sure that the plants used are free of pesticides and herbicides, otherwise, they may slow down your germination and growth rates.
If you have not tested your soils, run, don’t walk, and get them tested right now. Attempting to grow plants without knowing your soil leaves you flying blind - what do your plants really need? What is your soil missing? And how can you give it to them if you don’t know?
Experts recommend taking soil tests in the late summer or early fall, and then either processing them yourself or sending them to a lab.
There are scores of kits and testing probes available for purchase online, and even the most simple ones will give you insight into your soil’s acidity and moisture, as well as the levels of nitrogen, potassium, and nitrogen. Many of these tests require no advanced knowledge, they have detailed instructions and charts that will help you understand your results. If your soils are severely lacking in a vital nutrient for your plants, wouldn’t you want to know right now?
A professional soil test will get you more detailed results than a home kit, of course - a lab may also tell you about toxicity levels in the soil, the quantity of organic matter, and various nutrients that are present or absent. Always make sure the lab you use is licensed in your state.
Once you are armed with good information, it’s time to act upon it. Amend your soil with the nutrients it is missing, improve your drainage, add compost, clean any contaminants you discovered - once your soil is healthy and balanced, your crops will grow and thrive.
At Minick, we are experts in soil, with decades in the business backing us up. Our experts will be happy to help you amend or build the soil you need to achieve maximum productivity and growth. We deliver nationwide, and we’re as comfortable with large-scale commercial orders as we are helping you with a backyard DIY project. Give us a call and let’s talk about soil!