Is there nutrients in the soil… why do we need to fertilize when planting trees?
Plant cultivation nowadays for livelihood, consumption, or ornamental purposes, requires the use of fertilizers to promote flowering, fruiting, and overall plant growth. Have you ever wondered why fertilizers are necessary and where they go after application? Is it possible to skip fertilization, and will plants still thrive? Let's begin by discussing the essential and widely accepted plant nutrients which are categorized into 17 elements divided into two groups. There are
- Macronutrients or Major elements are essential plant nutrients required in large quantities. The concentration of these nutrients is measured based on dry weight when the plant reaches maturity and exceeds 500 ppm. The macronutrients include carbon, hydrogen, and oxygen which plants obtain from water and air. Nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur are obtained by plants from the soil. Nitrogen, phosphorus, and potassium are often collectively referred to as primary or fertilizer elements since plants require them in larger amounts than what is typically available in the soil. Calcium, magnesium, and sulfur, on the other hand that known as secondary or micronutrients while deficiencies in the latter group are less common in regular soil. Calcium and magnesium are sometimes referred to as lime nutrients due to their association with limestone used to address soil acidity issues.
- Micronutrient elements or Trace elements are essential plant nutrients required in smaller quantities with a concentration of less than 100 ppm based on dry weight when the plant reaches maturity. These micronutrients are crucial for various plant functions. The micronutrient elements include iron, manganese, zinc, copper, boron, molybdenum, chlorine, and nickel.
- Runoff process: If there is excessive watering or heavy rainfall, it can lead to the leaching of nutrients causing them to wash away from the area.
- Volatilization process: Nitrogen in the form of ammonium ions (NH₄⁺) will undergo a transformation into gaseous ammonia (NH₃), which is then released into the air.
- Denitrification process: This occurs extensively in soils with large amounts of undecomposed plant residues. When these plant residues are present in the soil, microorganisms rapidly decompose them, increasing their population swiftly. Meanwhile, the increased microbial population draws nitrogen from the soil and fertilizers for their use.
- Immobilization process: Significant ammonification occurs in soils with a large amount of undecomposed plant residues. When these plant residues are present in the soil, microorganisms rapidly decompose them, increasing their own population. Simultaneously, the increased microbial population enhances the process of ammonification, drawing nitrogen from the soil and fertilizers for utilization.
- The land condition is not conducive to agricultural productivity due to various characteristics of the soil. Properties such as the chemical composition of the soil being excessively acidic hinder the growth of plants. This acidity leads to the dissolution of iron and the precipitation of phosphorus, transforming it into water-insoluble compounds, rendering it unusable for plants. The physical aspects of the soil suffer from structural degradation, resulting in compaction and a lack of porosity. This makes it difficult for plant roots to penetrate and access nutrients.
