Leachable Nutrients

What Are Leachable Nutrients?

The term leaching is believed to have been derived either from the late Middle English term ‘leche’ or the Old English term ‘leccan’ which means to moisten and to allow leaking. Leaching can be described as the loss of soluble substances or small particles through soil or rock, due to rain and irrigation. Leaching can also be considered to be the practice of applying a small amount of surplus irrigation where the salt content in the water is high. This is done to avoid salts from accumulating in the soil. While carrying out the process of leaching, it is necessary to have a proper drainage system for carrying away the excess water. Leaching can be a cause of concern for the environment as it often leads to groundwater contamination, especially in regions with intensive agriculture. During leaching, valuable plant nutrients are lost in the soil. This may sometimes change the soil structure. Nutrients that are leached below the level of the roots are most likely to be lost from the system, although there remains a possibility of these being recycled if the roots grow deeper. Nutrient leaching plays a big role in creating nutrient deficiency.

How Are Leachable Nutrients Beneficial?

Leaching can also be considered to be two important activities occurring in concurrence; the interaction of chemical with surfaces, and the movement of water. When the water passes through rocks and soil it comes in contact with the surfaces of the minerals. This can lead to the compounds on the surface of the minerals to become dissolved. Furthermore, the movement of water displaces and moves particles. Leaching can move around chemical compounds such as dissolved substances or larger materials like fragments of rock, decomposing plant materials, and microbes throughout the soil.

The soil is somewhat similar to a sponge. When it rains, the soil at the top absorbs as much water as possible, and in this way keeps the moisture available for the plants that grow there. When the soil gets filled with water, it begins to leak and travels downwards through the layers of rocks and subsoil. Once water reaches the bottom, it takes soluble chemicals such as nitrogen and other fertilizer components, and other toxic elements as well along with it. When the soil is more porous, it becomes more susceptible to leaching. It becomes easier for the chemicals and other components to pass through. Pure sand is most suitable for leaching. When a vegetation or garden has more sand, it is more likely to be vulnerable to leaching. Soil, on the other hand, is more of a clay components and has less chances of facing leaching issues. When elements leach from the plants and gets passed through the soil into the water table, it poses as a threat to the environment. Leaching, as a result, is more of an environmental concern rather than a drainage issue. Leachable nutrients such as nitrogen and phosphorous are most often responsible for this.

Nitrogen is one of the most common elementsfound in the atmosphere and is very essential for nutrition in plants. It covers approximately 78% of the Earth’s environment. Nitrogen assists in plant growth, and as nitrogen naturally cycles through the air, water, and soil, it goes through various transformation, both chemically and biologically. Nitrogen leaching is affected by the type of soil and its structure, the amount of water that is absorbed by the plants, and the amount of nitrate that is already present in the soil. Nitrate leaching is also heavily responsible for acidification of the soil.

Phosphorous is also an essential nutrient regarding the presence of excessive minerals and nutrients in water bodies. Loss of phosphorous from a vegetation or garden is one of the biggest threats to surface water quality. Leaching is a crucial transport route for phosphorous loss from agricultural lands, mostly in flat areas with sandy soils or soils prone to favorable flow. Unlike nitrogen, phosphorous interacts with soil particles through adsorption and desorption.

Mobile Nutrients

What Are Mobile Nutrients

The growth and development of plants highly depends on nutrients acquired from the soil, air, or through fertilizers. Nutrients are essential for the growth of a plant, and they differ in their ability to move within the plant. The demand of nutrients keeps changing throughout the life of the plant. It generally increases during vegetative growth, and decreases during reproductive development. When inside the plant, nutrients are transported to the locations where they are necessary, generally to the points of growth. Once nutrients are absorbed by the plant, some elements can be mobile while others can be immobile. Nutrient mobility influences redistribution of nutrients and the fertilization of crops.Mobile nutrients can leave their original location and move to areas where the requirement is more, and immobile elements normally get locked in place and stay there. If one knows how nutrients move within the plants, then it can become a lot easier in diagnosing deficiency symptoms. The deficiency symptoms of mobile nutrients can be first seen in the older leaves as the nutrients are transported to new growth from there. Immobile nutrient deficiencies can be first seen in the new growth as the plant cannot take ample amount of nutrients to transport them to the new shoots.

What Are The Mobile Nutrients

There are eighteen elements, found in the nature, which can be considered necessary for plant growth and nutrition. Each of these elements has their own functions in the plant, and differs in characteristics and in the level in which they are required. Three out of these eighteen elements are non-minerals and the rest are minerals. The non-mineral elements are carbon (C), hydrogen (H)and oxygen(O). These elements are used within the physical plant structure, and are obtained from the environment (from carbon dioxide, CO₂) and water (H₂O). They form the basis for carbohydrates such as sugars and starch and acts as the source of energy for the plant.The minerals can be further classified into primary and secondary macronutrients and micronutrients. Plants need macronutrients in comparatively large amounts and micronutrients are required in smaller amounts. The requirement of nutrients increases as the plant grows.If nutrients are deficient or present in excess amounts, then plant will be damaged by slowing down or constraining the growth. Most of the time deficiencies can be identified by observing plants.

Primary Macronutrients

Primary macronutrients comprise of nitrogen (N), phosphorous (P), and potassium (K), which contributes to nutrient content of plants, function of plant enzymes and biomechanical processes. If macronutrient are present in deficit amounts it will result in reduced plant growth and yield. These three elements are considered most important nutrients that are absorbed from fertilizers.Secondary macronutrients comprise of calcium (Ca), magnesium (Mg) and sulfur (S).

Primary Micronutrients

Micronutrients, even though used in very small quantities, are also essential for plant growth and survival. These include boron (B), copper (Cu),iron (Fe), molybdenum (Mo), zinc (Zn), chlorine (Cl), manganese (Mn), cobalt (Co) and nickel (Ni).

Mobility in plants- In the plant, nitrogen, phosphorous, potassiumand magnesium are very mobile. Suplhur, copper, iron, molybdenum, zinc, and manganese are moderately mobile. Calcium and boron are immobile nutrients.

Mobility in soil- In soil, nitrogen as nitrate, sulfur as sulfate, and boron are very mobile. Potassium, calcium, molybdenum and magnesium are moderately mobile. Organic nitrogen, phosphorous, copper, iron, zinc and manganese are immobile nutrients.