Biofilmed biofertilizers: application in agroecosystems.

Certain soil microbiota naturally exists as surface-attached microbial communities in a biofilm mode of growth. They have been shown to be more effective at functioning than monocultures or mixed cultures of microbes. Therefore, such beneficial biofilms have been formulated in vitro to be used as biofertilizers called biofilmed biofertilizers (BFBFs) in agriculture and plantations. In this chapter we describe the significance of the BFBFs in addressing many issues that affect the sustainability of agroecosystems. In the literature on conventional biofertilizers, it is seen that the importance of surface attachment of microbes and biofilm formation has not been identified, though there are several other reports on the effectiveness of naturally occurring biofilms on soil particles and plant surfaces. However, the density of such biofilms on plant surfaces, particularly on the root system, is too low to have a significant effect on plant growth, as revealed by improved plant growth with BFBF applications to several crops. The BFBFs render numerous biochemical and physiological benefits to plant growth, and improve soil quality, thus leading to a reduction of chemical fertilizer (CF) NPK use by 50% in various crops. This reduction has not been achieved by conventional biofertilizers so far. The role of BFBFs is to reinstate sustainability of degraded agroecosystems through breaking dormancy of the soil microbial seed bank, and in turn restoring microbial diversity and ecosystem functioning. Thus, the concept of BFBFs is not only biofertilization, but also an holistic ecosystem approach. These formulations should therefore be considered as biofilmed microbial ameliorators (BMAs), rather than the BFBFs. If this agronomic practice were adopted in the future, it would lead to a more eco-friendly agriculture with an array of benefits to health, economics and the environment.