The increasing population has led to an increase in food demand and hence increasing agriculture production is necessary. This increasing demand has led the farmers to use fertilizer in such a quantity that soil health has started degrading. As a result, soil requires more nutrients for healthy plants and better productivity. Nitrogen, Potassium, Calcium, Boron, Zinc, Phosphorus and other nutrients are required for healthy plant growth. Plants need phosphorus for processes like energy transfer, DNA, RNA, ATP (adenosine triphosphate), root development, photosynthesis, and overall plant growth and reproduction. Phosphate Solubilizing Bacteria has a great impact on making Phosphorus available for plants in the soil.
Phosphorus is the second most important macro nutrient and the primary nutrient for the growth and development of the plant. Phosphorus is available in insoluble form in the soil, hence this insoluble form needs to be fixed in soluble form so that plants can uptake it. The Biofertilizer Phosphorus Solubilizing Bacteria from Peptech Biosciences can help in fixing this problem. In this blog, we will discuss how it can do this and can help boost the yield of the crops.
What are Phosphate solubilizing bacteria (PSB)?
Plants primarily absorb phosphorus in the form of orthophosphate ions (H2PO4– and HPO42-) from the soil. Hence PSB are beneficial bacteria that are capable of converting the unavailable form of phosphorus to available form by solubilising it in the soil through biological processes. They help in mobilizing the phosphorus in soil. There are different types of Phosphate Solubilizing Bacteria which includes Pseudomonas, Bacillus, Rhizobium, Enterobacter, Azotobacter, and Burkholderia. These all bacteria interact with the roots of plant and soil minerals near the root zone and increase nutrient bioavailability. To understand how these bacteria work, let’s explore their mode of action.
Mode of action: The science behind it
These bacteria secrete organic acids, enzymes, and other biochemical agents that break down phosphate bonds, releasing phosphorus into the soil. Let’s understand these processes in detail.
Production of organic acids
Phosphate Solubilizing Bacteria produces organic acids like gluconic acid, citric acid, lactic acid and acetic acid. These acids decrease the soil pH making the soil favorable to release more phosphorus. The acids released break the binding bonds of compounds and release the phosphorus ions into the soil to make them available for plant uptake.
Enzyme secretion
Phosphate Solubilizing Bacteria plays an important role in secreting enzymes. It releases enzymes like phosphatases and phytases which break down the complex organic phosphorous compounds to a simpler form or inorganic form. These enzymes hydrolyse the organic phosphorus present in the plant residue and organic matter. This microbial process increases the phosphorus availability and reduces the dependency on synthetic fertilizer.
Protone extrusion
Some species of Phosphate Solubilizing Bacteria increase the phosphorus availability by proton extrusion. It is a process in which the bacteria releases the hydrogen ion in the soil, which leads to an increase in hydrogen concentration in the soil, which acidifies the soil, promoting the dissolution of insoluble mineral phosphates. This process also contributes to the overall soil nutrient cycle, which improves the soil fertility.
Chelation of metal ion
PSB produces siderophores and other chelation agents that bind to metals like Fe³⁺ and Al³⁺. These metals generally react with phosphate, which forms insoluble complex compounds, making phosphorus unavailable for plants. By isolating these metal ions, PSB prevents phosphorus fixing, making more quantity in available form.
Application of Phosphorous Solubilising Bacteria in agriculture
It is largely used in agriculture crops, including cereals, legumes, fruits and vegetables. PSB can be used by the following methods:
Seed treatment
This involves coating of the seeds with PSB formulation some time before sowing in the field. It ensures early colonization of the rhizosphere improving the plant efficiency to uptake the phosphorus from the starting of its growth cycle. It promotes better root growth and improves seedling vigor. This method is cost effective and eco friendly.
Soil application
Soil application is done by mixing its culture with farm yard manure or with compost before applying in the soil. This improves the phosphorus availability by enhancing microbial activity near the root zone. This method also improves the soil aeration, soil water holding capacity and overall soil health.
These application methods help in better development of various crops. Some crops that can be benefited by its application are as follows.
Cereals like Rice and Wheat
Phosphate Solubilizing Bacteria play an important role in root development, energy transfer, grain formation and more nutrient absorption, leading to better grain filling, improved tillering, and higher yields.
Sugarcane
In sugarcane, it helps in enhancing the root growth and increases the sugar content of canes.
Legumes (Soybean, Chickpea, Pea)
Phosphate Solubilizing Bacteria work symbiotically with rhizobium bacteria. When rhizobium fixes atmospheric nitrogen, PSB improves phosphorus solubilization ensuring the optimal supply of both essential nutrients. This mutual interaction promotes better root nodulation and increases nitrogen fixation efficiency, and improves overall plant growth and yield.
Vegetables (Tomato, Brinjal, Cabbage)
It supports strong root development, vigorous vegetative growth, and higher yields. Increased phosphorus availability also strengthens the plants natural defence mechanism, which makes crops more resilient to environmental stress and diseases.
Fruits
In fruit crops, it plays an important role in enhancing root proliferation and nutrient absorption. This improves the fruit production and quality. It also helps in increased flowering and fruit set, leading to increased yield and more profit for the grower.
Future of Phosphate Solubilizing Bacteria
Its use in agriculture will continuously increase as the perfect alternative of chemical fertilizers. As the concern on soil degradation and water pollution is increasing it provides a promising solution for efficient phosphorus management. Integration of PSB with other biofertilizers enables the development of multifunctional biofertilizers which combine it with nitrogen fixing and plant growth promoting bacteria for enhanced crop productivity. In future some research may target the genetic modification of Phosphate Solubilizing Bacteria so that its phosphorous solubilizing efficiency can be increased.
Conclusion
The application of Phosphate Solubilizing Bacteria via inoculation in soil seems an effective means for transformation of the insoluble phosphate compounds into plant-available phosphate form leading to enhanced growth, yield, and quality in plants. It presents an eco-friendly alternative to traditional chemical fertilizers providing an economical way of enriching agricultural soil with the required essential phosphorus. With the increasing demand for sustainable solutions in modern agriculture, PSB based biofertilizers hold great promise for improving crop yields while preserving soil health and minimizing environmental impacts. Encouraging its use in farming systems can play a pivotal role in achieving long-term agricultural sustainability.