The Impact of Organic Matter Content in Organic Fertilizers on Fertilizer Efficiency

Organic fertilizers, mainly derived from plants and/or animals, are carbon-containing organic materials that have undergone fermentation and decomposition. One of their core components is organic matter, which is like the "soul" of organic fertilizers and plays an irreplaceable role in soil and crops.​

Abundant organic matter in the soil can significantly improve the soil structure. It acts like a "binder" for the soil, promoting the formation of aggregate structures from soil particles, increasing soil porosity, and thereby enhancing the soil's air permeability and water retention capacity. For example, in some soils that have long been using organic fertilizers with high organic matter content, the root systems of crops grow more developed and can take root better. This is due to the good soil structure providing sufficient space and a suitable environment for the root systems, allowing them to easily penetrate the soil, extend to a wider area, and improve the crop's stress resistance and adaptability.​

From the perspective of nutrient supply, organic matter can be regarded as a "treasure trove of nutrients". In the soil, organic matter will gradually decompose under the action of microorganisms, releasing a large number of elements such as nitrogen, phosphorus, and potassium, as well as medium and trace elements such as calcium, magnesium, and zinc. This process of nutrient release is relatively slow and long-lasting, which can provide stable nutrient support for crops throughout their growth period, avoiding the waste and seedling burning phenomenon caused by the rapid release of nutrients in a short period like chemical fertilizers.

what is the specific relationship between organic matter content and fertilizer efficiency?

Generally speaking, within a reasonable range, a higher organic matter content can improve fertilizer efficiency. Because abundant organic matter provides sufficient "food" for soil microorganisms, promoting their massive reproduction and active metabolism. While decomposing organic matter, these microorganisms can convert the nutrients in it into forms that are more easily absorbed by crops, enhancing the soil's fertilizer supply capacity. Moreover, high organic matter content helps to increase the cation exchange capacity of the soil, enabling the soil to better absorb and retain nutrients, reduce nutrient loss, and further improve fertilizer utilization efficiency.​

Different types of organic fertilizers have significant differences in their organic matter content. 

Organic fertilizers processed mainly from straw usually have a high organic matter content, which can be close to 90%, but their nutrient content is relatively low, and the nutrient release rate is slow. However, precisely because of this, they perform excellently in improving the soil. Livestock and poultry manure-based organic fertilizers have relatively lower organic matter content but higher nutrient content, and are more prominent in supplying nutrients to crops. Therefore, in actual agricultural production, it is necessary to select suitable organic fertilizers according to crop needs and soil conditions.​

It is worth noting that a higher organic matter content is not necessarily better.

When the organic matter content is too high, on the one hand, it may mean that the organic fertilizer is not fully decomposed. After being applied to the soil, it will continue to ferment, generating heat and harmful gases, which will damage the crop roots. On the other hand, an excessively high organic matter content may also lead to the excessive reproduction of microorganisms in the soil, which compete with crops for nutrients, and thus are not conducive to crop growth. Moreover, from an economic perspective, organic fertilizers with excessively high organic matter content may have higher costs and may not be cost-effective. A scientific research shows that after decomposition, the organic matter content of general organic raw materials is more appropriate between 35% and 45%.​

The organic matter content in organic fertilizers is a key factor affecting fertilizer efficiency. It improves fertilizer efficiency through various aspects such as improving soil structure, continuously supplying nutrients, and promoting microbial activity. However, it is necessary to reasonably control the organic matter content and scientifically select and apply organic fertilizers to achieve a win-win situation of soil health, high crop yield and quality, and economic benefits in agricultural production.