Organic fertilizer refers to any fertilizer derived from organic materials, typically containing carbon compounds. These fertilizers are commonly made from the remains of deceased plants and animals, as well as animal excrement. Organic fertilizers can be categorized into commercial organic fertilizers and farmyard manure. The latter includes soil manure, stable manure, dung, compost, green manure, and human waste. But what are the benefits of using organic fertilizers?
1. Enhances Soil Aggregate Structure
Soil aggregate structure is formed when individual soil particles bind together to create clusters known as aggregates. These structures create small pores that retain moisture and larger pores that allow air circulation. A well-structured soil with aggregates promotes healthy root growth, making it ideal for crop cultivation.
Benefits of soil aggregates for soil fertility:
- Balances moisture and air: Ensures adequate air circulation while retaining moisture.
- Nutrient management: Coordinates the consumption and accumulation of nutrients in soil organic matter.
- Temperature stability: Stabilizes soil temperature and regulates heat conditions.
- Improves tillage: Enhances soil workability and supports root expansion.
2. Organic Fertilizer Improves Soil Aeration and Looseness
For fruit trees to complete their nutrient cycles, their surface-level roots require a sufficient oxygen supply. This necessitates soil that is both loose and well-aerated. Soil aeration, the process by which soil air exchanges with the atmosphere, is crucial for plant growth and is influenced by soil structure, moisture content, temperature, and other environmental factors. Well-structured soil, particularly with high total porosity or a significant proportion of large pores, exhibits excellent aeration.
3. Regulates Soil Acidity and Alkalinity
Soil pH is a measure of soil acidity or alkalinity. Soil pH is determined by the concentration of hydrogen ions (H⁺) and hydroxide ions (OH⁻). When the concentration of H⁺ exceeds OH⁻, the soil becomes acidic; when OH⁻ predominates, the soil becomes alkaline; and when the two are balanced, the soil is neutral. In China, soil pH typically ranges from 4.5 to 8.5, with a trend of “acidic in the south, alkaline in the north” due to climatic differences. Excessive acidity or alkalinity can decrease soil nutrient availability, inhibit microbial activity, and negatively affect crop growth.
4. Improves Agricultural Product Quality
Changes in key organic components of fruit:
- Water content: Most fruits contain 80-90% water, except for nuts and dried fruits like chestnuts and walnuts.
- Sugar and acid content: The sugar and acid levels, as well as their ratio, are crucial indicators of fruit quality. Different types of sugar, such as glucose, fructose, and sucrose, and various organic acids like malic acid, citric acid, and tartaric acid, affect taste and nutritional value.
- Pectin: The firmness of fruit is influenced by pectin, which binds cells together. As fruit ripens, pectin transforms, softening the flesh.
- Aroma and flavor: The aroma and flavor of fruit are essential quality factors, influenced by tannins, flavonoids, and other compounds. The presence of vitamins, pigments, and other nutrients also plays a role.
5. Organic Fertilizer Provides a Wide Range of Nutrients
Organic fertilizers contain not only organic matter and acids such as humic acid, amino acids, and fulvic acid but also a variety of macro, meso, and micronutrients. Although the nutrient levels may be lower compared to chemical fertilizers, they are more comprehensive. For example:
- Nitrogen: Promotes leaf growth.
- Phosphorus: Enhances flower development.
- Potassium: Supports fruit production.
- Silicon, calcium, and magnesium: Protect roots, fruits, and leaves, respectively.
- Micronutrients: Iron prevents yellowing, copper prevents leaf drop, molybdenum prevents mottled leaves, zinc prevents small leaves, and boron prevents leaf curling.
6. Offers Long-Lasting Effects
True organic fertilizers do not dissolve in water because they contain large amounts of cellulose and lignin, which require microbial decomposition in the soil. This slow process converts these materials into amino acids and carbohydrates, providing a sustained nutrient release for plants.
7. Increases Fertilizer Efficiency
When organic fertilizers decompose, they provide energy and nutrients for soil microbes, boosting their activity. This accelerated microbial activity enhances the breakdown of organic matter and the release of active substances that promote plant growth and improve the quality of agricultural products. Additionally, the organic acids produced during decomposition help release and utilize mineral nutrients that are otherwise locked in the soil.
8. Organic Fertilizer Improves Soil Water Retention
Research shows that humus in organic fertilizers contains fats, waxes, and resins, which can infiltrate soil aggregates, making them hydrophobic. This reduces the soil’s wetting process and slows capillary water movement, decreasing evaporation and enhancing soil water retention. The soil’s aggregate structure, particularly when rich in water-stable aggregates, ensures good soil looseness, which improves water infiltration and reduces surface evaporation.
9. Regulates Soil Temperature
Organic fertilizers have the ability to absorb and retain heat, which is beneficial for the sprouting and growth of plant roots. During decomposition, organic fertilizers release heat, increasing soil temperature. With a high heat capacity, organic fertilizers also maintain a stable soil temperature, protecting plants from extreme temperature fluctuations—preventing freezing in winter and overheating in summer. This is particularly advantageous for the growth and winter survival of fruit trees.
10. Indicator of Soil Fertility
Soil organic matter is a crucial component of soil, derived from biological sources. It serves as a primary source of nutrients for plants, promotes plant growth, enhances soil physical properties, and stimulates microbial and soil biological activity. The content of organic matter in soil is closely related to soil structure, aeration, permeability, adsorption, and buffering capacity. Generally, under similar conditions, the amount of organic matter correlates positively with soil fertility levels. Organic fertilizers can significantly increase soil organic matter, making them an important tool for improving soil fertility.
Soil organic matter refers to the substances in the soil that come from life. Soil organic matter is an important component of the solid phase of the soil and one of the main sources of plant nutrition. It can promote the growth and development of plants, improve the physical properties of the soil, promote the activities of microorganisms and soil organisms, promote the decomposition of nutrients in the soil, and improve the soil’s fertility retention and buffering properties. It is closely related to the structure, aeration, permeability, adsorption, and buffering properties of the soil. Usually, under the same or similar conditions, within a certain content range, the content of organic matter is positively correlated with the soil fertility level.
The content of soil organic matter is one of the important indicators for testing soil fertility, and organic fertilizer can increase the content of soil organic matter.
