Chemical fertilizers are typically divided into two categories: macronutrient fertilizers and micronutrient fertilizers.
Macronutrient Fertilizers
Macronutrient fertilizers are essential for crops as they absorb and consume these nutrients in large quantities. These include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). These nutrients play crucial roles in crop growth, providing the necessary large-scale nutrition that crops require.
Micronutrient Fertilizers
Micronutrient fertilizers, also known as "micro-fertilizers," contain trace elements. Although crops need these elements in smaller amounts, they are equally vital for plant growth and development and cannot be substituted. Common micronutrient fertilizers include boron (B), zinc (Zn), manganese (Mn), molybdenum (Mo), copper (Cu), iron (Fe), and cobalt (Co).
Micronutrient fertilizers demonstrate their highest efficacy when used alongside macronutrient fertilizers such as N, P, and K. Different levels of nitrogen, phosphorus, and potassium can affect the crop’s micronutrient requirements. Generally, low-yield soils are more prone to micronutrient deficiencies, whereas in high-yield soils, the demand for micronutrients increases with yield. Therefore, supplementing with micronutrient fertilizers is necessary, but it cannot replace the use of macronutrient fertilizers to achieve high yields.
Distribution of Micronutrients in the Natural Environment
All substances in nature, including plants, animals, minerals, rocks, air, and water, are composed of various chemical elements. These elements can be classified into macronutrients, mesonutrients, and micronutrients based on their abundance. Macronutrients are present in high amounts, micronutrients in very low amounts, and mesonutrients fall somewhere in between.
Role of Micronutrients in Soil
Micronutrients in soil can refer to all chemical elements present in low concentrations or specifically to those that have biological significance for plant growth and development. Biologically significant micronutrients often form part of enzymes or coenzymes, having specific functions that are indispensable for the normal growth and development of organisms.
Types of Micronutrient Fertilizers
In China, commonly promoted or soon-to-be-applied micronutrient fertilizers include boron fertilizers, molybdenum fertilizers, zinc fertilizers, copper fertilizers, manganese fertilizers, and iron fertilizers. These fertilizers play irreplaceable roles when applied to crops, trees, pastures, fruit trees, and vegetables. Micronutrient fertilizers can be classified into several types based on their nutritional content:
- Simple Micronutrient Fertilizers: Contain only one type of micronutrient element needed by crops, such as zinc sulfate and ferrous sulfate. These are water-soluble and easy to apply.
- Compound Micronutrient Fertilizers: Contain one or more micronutrients combined with macronutrients or other micronutrients, such as ammonium zinc phosphate and ammonium manganese phosphate.
- Mixed Micronutrient Fertilizers: A mixture of various simple fertilizers tailored to specific needs, often mixed at fertilizer stations according to user requirements.
Based on the type of chemical compounds, micronutrient fertilizers can also be divided into:
- Easily Soluble Inorganic Salts: Such as sulfates.
- Poorly Soluble Inorganic Salts: Such as phosphates and carbonates, suitable for use as base fertilizers.
- Glass Fertilizers: Silicon compound powders containing trace elements, sintered or melted into glass-like substances.
- Chelated Fertilizers: Natural or synthetically produced chelates, combined with micronutrients.
- Industrial Waste Residues Containing Micronutrients: Such as slag from smelters.
Integration of Kitchen Waste Disposers
Kitchen waste disposers can play a pivotal role in sustainable agriculture by transforming organic kitchen waste into nutrient-rich compost. This compost not only provides essential micronutrients but also improves soil structure and health. By integrating kitchen waste disposers, households and farms can contribute to a circular economy, reducing waste and enhancing the availability of natural fertilizers. This approach complements the use of chemical fertilizers, ensuring a balanced supply of nutrients and fostering a more sustainable agricultural practice.
