**2.** *Trichoderma* **as a biofertilizer**

*Trichoderma* has been reported to promote plant growth in various ways. Some people have used it as a biofertilizer because of its ability to stimulate plant growth of many crops. It comes as an alternative to chemical fertilizer or as an amendment to improve crop production. Many attributes qualifies it to be used as an alternative or amendment to improve fertilization sustainably. Some of them are the following facts:


#### **2.1 Production of plant growth hormones and volatile compounds**

Plant growth hormones are also called phytohormones. They are involved in many processes in the plant including communication, biotic and abiotic stress management, and many more processes. They have been reported for many years to play a vital role in the growth and development of a crop. Root and shoot elongation needs phyto-hormones to happen properly at the correct speed that supports high productivity. It has been reported that the presence of *Trichoderma* increases the production of some growth hormones such as indole-3-acetic acid (IAA) and gibberellic

#### Trichoderma*: A Biofertilizer and a Bio-Fungicide for Sustainable Crop Production DOI: http://dx.doi.org/10.5772/intechopen.102405*

acid [15]. These two hormones are important in promoting plant growth, they are responsible for plant elongation [7]. As stated in **Table 1**, *Trichoderma* also improves germination rate and improves seedling vigor, which is an advantage for the crop. This is also associated with balanced phytohormones.


#### **Table 1.**

*Production of plant growth hormones and volatile compounds by Trichoderma to improve plant growth.*

#### **2.2 Solubilization of phosphates**

Phosphorus is one of the critical nutrients that plants need for their growth and development. It is found in the soil but due to depletion farmers have to apply fertilizers. However, the availability of phosphorus to the crop depends on the form it is in. Acidic soils bind phosphorus and make it unavailable to the crop, which is an undesired outcome [20]. Due to this, the accuracy of the amount required by the crop may not be achieved resulting in challenges associated with lack or insufficient phosphorus in the soil [3]. Some microorganisms mediate this process by solubilizing phosphates, converting them back to be in the available form for crop utilization. *Trichoderma* species have been reported to be one of those organisms. Species such as *Trichoderma harzianum* [21], *Trichoderma reesei* [22], solubilize phosphates through the production

of enzymes called phytase. The phytase activity is induced by the presence of insoluble tricalcium phosphate [5]. Other *Trichoderma* species such as *Trichoderma koningiopsis* solubilize phosphates by producing alkaline phosphatase enzymes (**Table 2**) [6].


**Table 2.**

*Solubilization of phosphates by Trichoderma to promote plant growth.*
