Can soil have too much organic matter and how much water wills 1% organic matter holds and does organic matter affect nutrient retention?
Yes, soil can have too much organic matter. While organic matter is essential for healthy soil, too much can lead to problems such as:
- Nutrient tie-up: Organic matter can bind nutrients in the soil, making them unavailable to plants.
- Poor drainage: High levels of organic matter can make soil too spongy, preventing water from draining properly. This can lead to root rot and other problems.
- Pests and diseases: Organic matter can provide a breeding ground for pests and diseases.
- Nutrient leaching: High levels of organic matter can increase the risk of nutrients leaching out of the soil and into waterways.
The amount of water that 1% organic matter holds depends on a number of factors, including the type of organic matter, the particle size, and the pH of the soil. However, as a general rule of thumb, 1% organic matter can hold about 0.5% water.
Yes, organic matter affects nutrient retention. Organic matter is a major reservoir of nutrients in the soil. It can hold nutrients such as nitrogen, phosphorus, and potassium. Organic matter also helps to improve soil structure, which can also improve nutrient retention.
How to avoid too much organic matter in soil:
- Get a soil test to determine the organic matter content of your soil.
- Add compost or other organic matter in moderation.
- Choose organic matter that is well-decomposed.
- Grow cover crops to help improve soil structure and nutrient retention.
If you have too much organic matter in your soil, you can reduce it by:
- Adding sand or other coarse material to improve drainage.
- Growing plants that have deep roots, which will help to break up the soil.
- Avoiding over-fertilizing.
Yes, for each 1-percent increase in soil organic matter, the available water holding capacity in the soil increased by 3.7 percent. Soil water is held by adhesive and cohesive forces within the soil and an increase in pore space will lead to an increase in water holding capacity of the soil. Too much compost or other organic matter, however, can increase the phosphorus concentration in soils to the point where the element may become a pollutant. So have your soil tested regularly to make sure it holds 20 to 40 pounds per acre of available phosphorus. The source of soil organic matter is photosynthesis resulting in plant growth either root or aboveground. Therefore, the organic matter content cannot increase more than the amount of plant growth that can be produced in a year. Every 1% increase in organic matter results in as much as 25,000 gallons of available soil water per acre. Each pound of soil organic matter (SOM) can hold up to 18 to 20 pounds of water and 1% of SOM can hold up to 1 inch of water in the soil. Fine-textured soils, containing high percentages of clay and silt, tend to have naturally higher amounts of soil organic matter than coarse-textured sands or sandy loams. CEC is produced during the decomposition process, increasing the soil's ability to retain calcium, potassium, magnesium and ammonium. Organic molecules are produced that hold and protect a number of micronutrients, such as zinc and iron. The addition of organic matter to the soil usually increases the water holding capacity of the soil. This is because the addition of organic matter increases the number of micropores and macropores in the soil either by “gluing” soil particles together or by creating favorable living conditions for soil organisms. Increasing levels of organic matter aid in soil structure, water-holding capacity, nutrient mineralization, biological activity, and water and air infiltration rates. As soil organic matter is derived mainly from plant residues, it contains all of the essential plant nutrients. Therefore, accumulated organic matter is a storehouse of plant nutrients. The stable organic fraction (humus) adsorbs and holds nutrients in a plant-available form. Soil organic matter significantly improves the soil's capacity to store and supply essential nutrients (such as nitrogen, phosphorus, potassium, calcium and magnesium), and to retain toxic elements. It allows the soil to cope with changes in soil acidity, and helps soil minerals to decompose faster. Restoration of the soil organic matter (SOM) content of degraded/depleted soils can increase soil water retention (SWR) more at field capacity (FC) than that at the permanent wilting point (PWP), and thus increase the plant available water capacity (PAWC).