Bioavailable sulphur

Bioavailable sulphur is an essential nutrient for plants and soil bacteria. It plays a key role in various metabolic processes, such as amino acid synthesis, enzyme activity, and stress tolerance. However, sulphur deficiency is a common problem in many agricultural soils, especially in regions with high rainfall and low organic matter. This can lead to reduced crop yields, poor quality, and increased susceptibility to diseases and pests.

Improve Sulphur in Soil

One way to improve the sulphur status of soils is to use biofertilizers that contain sulphur-oxidizing bacteria (SOB). These bacteria can convert insoluble forms of sulphur, such as sulphate minerals and elemental sulphur, into soluble forms that can be taken up by plants. SOB can also enhance the availability of other nutrients, such as nitrogen and phosphorus, by increasing soil pH and releasing organic acids.

Some examples of SOB that have been used as biofertilizers are Thiobacillus, Acidithiobacillus, and Sulfolobus. These bacteria can be isolated from various sources, such as hot springs, volcanic soils, and industrial wastes. They can be applied to the soil as pure cultures or mixed with organic materials, such as compost or manure. The effectiveness of SOB biofertilizers depends on several factors, such as the type and amount of sulphur source, the soil properties, the crop species, and the environmental conditions.

In this blog post, we will discuss the benefits and challenges of using SOB biofertilizers for improving the bioavailability of sulphur in soils. We will also review some recent studies that have evaluated the impact of SOB biofertilizers on plant growth, yield, and quality. Finally, we will provide some practical tips on how to select and apply SOB biofertilizers for different crops and soils.


Besides SOB, there are other types of biofertilizers that can improve the sulphur status of soils. For example, some nitrogen-fixing bacteria (NFB), such as Rhizobium and Azotobacter, can also produce sulphur-containing compounds that can be utilized by plants. Some phosphate-solubilizing bacteria (PSB), such as Bacillus, Paenibacillus,  and Pseudomonas, can also release sulphur from insoluble phosphates. Some mycorrhizal fungi (MF), such as Glomus and Gigaspora, can also enhance the uptake of sulphur by plants through their symbiotic association with plant roots. These biofertilizers can be used alone or in combination with SOB to increase the efficiency and sustainability of sulphur fertilization.

One of the most widely used NFB biofertilizers is Rhizobium, which forms nodules on the roots of leguminous plants, such as beans, peas, and clover. Rhizobium can fix atmospheric nitrogen into ammonia, which can be assimilated by plants. Rhizobium also produces cysteine and glutathione, which are rich in sulphur and can be used for protein synthesis and stress protection.

Rhizobium Biofertilizer

To apply Rhizobium biofertilizer, you need to inoculate the seeds or seedlings with a suitable strain of Rhizobium before planting. You can use commercial inoculants that are available in liquid or powder form. You should follow the instructions on the label for the dosage and method of application. You should also ensure that the inoculant is compatible with the plant species and cultivar that you are growing. You should also avoid using chemical fertilizers or pesticides that may harm or inhibit the growth of Rhizobium.

Bioavailable Sulphur

Rhizobium biofertilizer can improve the nitrogen and sulphur nutrition of leguminous plants and increase their yield and quality. It can also benefit non-leguminous crops that are grown in rotation with legumes by leaving residual nitrogen and sulphur in the soil.

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