The Secret of Fertile Soil: The Role of Nitrifying Bacteria and the Benefits of Biochar in Corn Fields

In the world of agriculture, soil is not merely a growing medium — it is a living ecosystem, full of microorganisms silently working to maintain fertility. One of the crucial processes occurring in soil is nitrification, the transformation of ammonia into nitrate, a form of nitrogen that plants can absorb. Without this process, plants would lack essential nutrients needed for healthy growth.

However, the excessive use of chemical fertilizers in agriculture — particularly in countries like China — often worsens soil quality. Besides having low fertilizer use efficiency, overapplication leads to soil acidification, environmental degradation, and water pollution. This raises an important question: how can we enhance soil fertility without causing environmental harm?

One promising answer is biochar, a type of charcoal made from organic materials such as agricultural waste. Biochar not only raises soil pH (neutralizing acidity), but also improves water and nutrient retention. But can biochar also support the activity of soil microbes, particularly those involved in nitrification?

A study conducted on corn fields revealed that combining biochar with chemical fertilizers (NPK) produced remarkable results. Soils treated with this combination showed a significant increase in nitrification activity, along with a rapid growth in populations of beneficial microbes such as:

• AOB (Ammonia-Oxidizing Bacteria): bacteria that convert ammonia into nitrite,

• Comammox Nitrospira: specialized bacteria capable of directly converting ammonia into nitrate, and

• NOB (Nitrite-Oxidizing Bacteria): such as Nitrobacter and Nitrospira, which further convert nitrite into nitrate.

Interestingly, while biochar alone already provided positive effects, the best results appeared when biochar and chemical fertilizers were combined. This combination not only increased the number of beneficial microbes but also improved the structure of the soil’s microbial community. Moreover, changes in the soil’s chemical properties — such as increased pH and nutrient levels — were found to strongly influence the activity of these microbes.

What does this mean for farmers? The combination of biochar and chemical fertilizers not only boosts crop yields but also promotes long-term soil health. Soil microbes, which have often been overlooked, such as the NOB group, are now known to play a crucial role in maintaining nitrogen availability in the soil. This suggests that agriculture can become more efficient and environmentally friendly by wisely integrating natural and modern approaches.

Balancing agricultural technology with nature is the key to success. Biochar offers a simple yet impactful solution to address challenges in soil fertility and food security. Though invisible to the naked eye, soil microbes are the true heroes behind abundant harvests.

Discover more about SAWA’s innovative biochar production and its impact on sustainable farming.

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