Microbial fertilizer and biochar: A synergistic and sustainable approach to boost crop and soil health

Focusing on the bottom of the problem

The soil and its microorganisms are important aspects in boosting the crop’s health and tolerance to pests and diseases and other stresses. However, continued industrialization, modernization, and non-sustainable agricultural practices resulted to poor soil health. These soils are often characterized by low nutrient content, low organic matter content, low microbial abundance and activity, poor aeration and water holding capacity, among others. Moreover, intensive application of pesticides and chemical contamination cause soil microbial population to decline. These problems reduce the soil’s agronomic potential.

Soil health including organic matter can be restored via application of soil amendment such as biochar while the use of microbial fertilizers will make soil nutrient more available to the plants.

Biochar: From waste to treasure

Biochar is a carbon-rich and porous material produced from agricultural wastes via a process called pyrolysis in the absence of oxygen. Aside from increasing the soil’s organic matter, biochar has a multitude of benefits including increased crop yield, improved soil physicochemical and biological properties, increased cation exchange capacity for nutrients, increased water retention so to reduce irrigation, and carbon sequestration. Some studies even claim that biochar stimulates microbial abundance and activity, and prevents soil-borne pests like nematodes. In addition, application of biochar has been proven to immobilize pesticide residues and in turn, prevents leaching.

Biochar is produced from mainly agricultural wastes. In the Philippines where it is highly agricultural, there is low utilization of crop wastes like coconut husks and shells, rice straws, and corn stalks. Production of biochar can be a promising strategy in managing these wastes.

Biofertilizers: The plants’ microbial friend

Biofertilizers, also known as microbial fertilizers, make nutrients that are naturally abundant in the soil or atmosphere more accessible for plants through microbe-plant symbiotic relationship. Some biofertilizers have shown to replace the crop’s fertilizer requirements by 60-85%. Biofertilizers improve soil fertility, crop productivity, tolerance to some diseases, and have the potential to bioremediate as fungi are tolerant to heavy metals.

Two is better than one

While there are other techniques in soil remediation, these two approaches are applicable to large fields, environment friendly, and cost-effective. Not only do they remediate soil but also, they increase crop yield and improve crop health.

There is also a possible synergistic or additive effect between the two. As biochar boosts soil health, biofertilizers may possibly benefit from it, making it more active to release more nutrients in the plant. This is a research gap and can therefore be studied along with other gaps such as impact on soil pesticide residues, effect on nematodes and other diseases.

Let’s make it happen

Biochar will be produced from selected agricultural waste/s while a particular biofertilizer product will be purchased from the University of the Philippines Los Baños. Several vegetable farmers will apply 1) biochar only, 2) microbial fertilizer only, 3) both products, and 4) without any of the products in one planting season for a selected crop. Then, results will be compared by several parameters including yield, cost, pest damage, degree of disease infestation, etc. Trainings will be conducted to disseminate knowledge about the technology.

If still possible, laboratory experiments will also be done to determine effect on microbial abundance and activity via phospholipid-derived fatty acids (PLFA) analysis, and DNA isolation and high-throughput sequencing. Effect on accessible soil pesticide concentration in soils could be studied via chromatographic analysis.

Beneficiaries of the project are the farmers for they will have greater utilization on agricultural wastes for production of biochar, and more specially to increase their crop productivity and income as these two reduce expensive farm inputs. Utilization and production of these products will also create more jobs. Researchers will benefit as their technologies will be transferred and they will determine the products’ impact on yield, soil properties, disease/pest, etc. Finally, it is the world in general that will benefit because of these sustainable, eco-friendly, and effective approaches. Biochar production, as a negative emission technology, will also offset global greenhouse gas emissions.

The story behind the story

I became interested on biochar and microbial fertilizers when I was doing a research in one of my graduate courses. It is not my research niche but I was curious about it. Though the biochar is not really a complex or advanced technology, I find its use really practical and I believe that we just have to utilize it and see its maximum potential. I found that it may stimulate microbial population and so I was curious of the possible effect with microbial fertilizers. Moreover, these two have the potential to reduce toxicity due to pesticides and heavy metals which is still an interesting research gap. I have not done any study yet regarding this idea but I am passionate to have a more comprehensive research study regarding this in the future when the right time comes.

Jasper A. Sarmiento, Philippines


  1. I’ll stay tuned for your next posts on biochar-related projects. I’ve read somewhere that biochar is also an excellent material for filtering water. Good luck!

    Liked by 1 person

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