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Humus

by Achim Dobermann
Published: Last Updated on
Humus

Humus, also known as organic matter or soil organic matter, is a crucial component of healthy soil. It is the product of the decomposition of dead plant and animal material by microorganisms, and it plays a key role in the soil ecosystem by providing nutrients and water-holding capacity for plants, and serving as a home for beneficial microorganisms.

Humus has a long history of use in agriculture, dating back to ancient civilizations such as the Egyptians, Greeks, and Romans, who recognized its importance for crop growth. However, it was not until the 19th century that scientists began to understand the chemical composition of humus and its role in soil fertility. Today, it is recognized as a vital component of healthy soil and is used in a variety of agricultural and horticultural applications.

Globally, the status of humus varies greatly depending on the region and type of land use. In natural ecosystems, humus is typically present in abundant quantities, serving as a source of nutrients and a home for beneficial microorganisms. However, in many agricultural and urban areas, it has been depleted through a combination of factors such as overuse of synthetic fertilizers, erosion, and the conversion of natural habitats to human-managed landscapes.

There is a growing body of scientific evidence that highlights the importance of humus in maintaining soil health. It is able to hold onto water and nutrients, making them available to plants when they need them. Additionally, humus serves as a habitat for beneficial microorganisms, which help to maintain a balanced ecosystem in the soil. These microorganisms help to break down nutrients, making them available for plant uptake, and they also play a role in the suppression of plant pathogens.

However, the depletion of humus has a range of negative effects on soil health and plant growth. For example, without an adequate supply of humus, soil may become compacted and water-logged, leading to poor drainage and a lack of oxygen for plant roots. Additionally, without the presence of beneficial microorganisms, soil may become overrun with pathogens, leading to a decline in plant health.

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There are a number of factors that contribute to the depletion of humus. One of the main causes is the overuse of synthetic fertilizers, which can lead to a loss of organic matter in the soil. Additionally, the conversion of natural habitats to human-managed landscapes, such as agriculture and urban development, can lead to a loss of organic matter through erosion and other forms of soil degradation.

Despite the importance of humus, there are several scientific concerns surrounding its management and use. One of these concerns is the lack of understanding about how to effectively manage humus in different types of soils and under different land use scenarios. Additionally, there is ongoing debate about the best methods for measuring humus levels in soil, and there is a lack of consensus on how to define “optimal” levels of humus.

Humus can be divided into two main types: fulvic acids and humic acids. Fulvic acids are the smallest and most mobile of the humic substances, while humic acids are larger and more complex. Both fulvic and humic acids play an important role in soil health by providing plants with essential nutrients, such as carbon, nitrogen, and phosphorus, and helping to maintain a balanced ecosystem in the soil.

It also plays an important role in the environment and climate change. The organic matter in humus can act as a carbon sink, which means it can store carbon in the soil. As carbon is taken in by plants through photosynthesis and then added to the soil as organic matter, it can be sequestered for long periods of time, reducing the amount of carbon in the atmosphere and helping to mitigate the effects of climate change. Additionally, a healthy soil with a high level of humus can improve water retention and reduce erosion, thus playing a vital role in conserving water and preventing soil loss.

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Despite the numerous benefits of it, its depletion remains a major concern globally. In order to address this issue, it is important to focus on sustainable land use practices that promote the conservation and restoration of humus. This includes reducing the use of synthetic fertilizers and pesticides, implementing conservation tillage and cover cropping, and increasing the incorporation of organic matter in the form of compost, manures and green manures.

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On global scale, it is important to have accurate statistics and figures on the humus levels in different regions, land-use types and soil conditions. This will help in identifying areas where its depletion is most severe and guide the implementation of targeted conservation measures.

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In conclusion, humus is a vital component of healthy soil and plays an important role in supporting plant growth and maintaining a balanced ecosystem in the soil. Despite the importance of humus, its depletion remains a major concern globally and sustainable land use practices are needed to conserve and restore humus. Therefore, accurate statistics and figures on humus levels in different regions and land-use types is important in identifying areas of severe depletion and guiding conservation efforts.

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