*2.5.2.2 Ectomycorrhizae*

These fungi form a thick mantle structure within the intercellular spaces of roots, but not in touch with cellular surface of roots. Being symbiotic with big trees, they increase tolerance of trees to abiotic stress while reducing the level of toxins in the soil and shielding roots from biotic stress as well. They are used in BF formulations for mobilizing phosphorus, iron, zinc, boron, and other trace elements.

There are many species/strains used in BF and it may not help in listing them here. Suffice it to state that Azospirillum, Pseudomonas, Aspergillus, Cladosporium, Macrophomina, Glomus, Trichoderma, and Penicillium are commonly used fungi of this group that activate nitrogen fixing, solubilization of phosphorus and potassium. Trichoderma fungi, ubiquitously present in roots and soil ecosystems, that thrive on decaying wood, soil, and organic matter are used as BF to harness soil nutrients and to increase the resistance of plants against diseases and abiotic stresses. It is an excellent fertilizer cum protector for potato, corn, and tomato etc. Other strains are not discussed here for want of space.

## **2.6 Farming practices (FPs)**

Farming activities standardized over course of time are termed as farming practices (FPs). The standardization is partly universal and partly specific to culture, climate, crop, and farm size. Current FPs include use of machines to prepare soil and use of chemicals to restore soil fertility and to control weeds or pests/diseases. These FPs became mainstream about 50 years back when green revolution was launched as a drive against starvation. This transformed farming from a way of life to an intensive agriculture. With harmful effects of these FPs being noticed, alternative FPs are being explored.

As stated earlier, farming activities aligned with natural ecosystem processes are good FPs. The good FPs result in good growth of crops with less effort of farmers and no harm to environment. Bad FPs, being against natural processes, demand more farming efforts and harm the environment. The natural ecosystem encourages existence of healthy organisms and cleanses sick/dead bodies through decomposition by microbes. Any bad FP harming the environment is an invitation for pests/diseases.

Comparing crop yields under good and bad FPs is a blunder as crop yield is only one parameter of farm productivity. Yield happens to be the most visible parameter and so simple that even a school dropout can calculate its monetary value. With greed being an irresistible instinct in humans, farmers are focused on the yield alone. After all, they are also humans. The external costs of restoring soil and human health are too enormous to be ignored, though invisible. In fact, even visible costs of chemicals (increasing every year) can offset the gain in crop yield by bad FPs. While ban on the chemicals is not intended here, indiscriminate use of chemicals by uninformed farmers warrants community action to respond to promotional assault of toxic chemicals and harmful practices from industrial agriculture lobby and to protect uninformed farmers by equipping them with unbiased information on right FPs.

As paper titled "Soil C Sequestration as a Biological Negative Emission Strategy" published in 2019 [7] outlines following conventional practices as best management practices (BMP).


Increasing SOC is, thus, essence of optimizing both productivity and SCS. The Rodale Institute (RI), supporting regenerative agriculture (RA) claimed in *Leveraging Soil Microbes with Good Farming Practices for Higher Soil Carbon Sequestration… DOI: http://dx.doi.org/10.5772/intechopen.105201*

its White Paper of Sep 2020 [8] that the RA practices can remove the atmospheric carbon dioxide levels at a rate higher than current anthropogenic emission rate. Some important RA practices listed below deserve a look.


Conservation agriculture (CA) also emphasizes on non-disturbance of soil, permanent soil cover, and crop-diversity to balance economics with ecology in agriculture. Discussion on farming as well as soil management is incomplete without mentioning Dr. Rattan Lal, eminent soil scientist from Ohio State University. His paper on societal value of soil carbon [9] is simply transformative. Below is given a discussion on activities of soil preparation, fertility restoration, and farming management.

#### *2.6.1 Soil preparation*

All over the world tilling or ploughing is common farming practice for preparation of soil. The farmers generally point out that tilling is necessary for solarization, aeration, ridging for placing seeds, loosening of compact soil, and removing weeds. However, these reasons do not hold much water when scrutinized closely. So, tilling goes on more as a tradition than as a necessity. In fact, tilling adversely affects soil health, crop productivity, and environment. The soil erosion caused by intensive tilling is the first apparent and proven harmful effect of tilling. The second harm is that it exposes the SOM to atmosphere resulting in its decomposition without any productive use and decline in soil fertility. The fact that tilling injures/kills soil microbes is the third serious harm of tilling. The carbon dioxide released by tilling accelerates the dreaded climate change which is the fourth harm. It is also the last one because no living organisms would be left on the planet to be harmed further. So, digging/tilling soil means digging our own graves. Suitable alternatives to tilling need to be evolved to obviate serious consequences. Current no-till farming is far from ideal while organic no-till can be ideal solution only when it is affordable. In the meanwhile, farmers may counter adverse effects of tilling by good FPs.

#### *2.6.2 Soil fertility restoration*

Movement of nutrients from soil to the growing plants results in depletion of nutrients in soil. Replenishment of nutrients is done by farmers by adding organic matter, manure, or other fertilizers. As organic matter (OM) is the food for soil microbes who maintain soil's wellbeing, adding OM to the soil supplies food to them besides supplying full suite of nutrients to the plants. The OM in soil helps in retaining moisture and formation of crumbly structure of soil that resists soil

compaction. It is also helpful in improvement of soil aeration and water drainage. These and many other benefits show the importance of SOM and SOC. Ultimately, the SOM and SOC also improve soil carbon sequestration.

While harmful effects of synthetic fertilizers are beyond debate, total prohibition of such fertilizers may not make economic or ecological sense because deficiency of specific nutrients needs to be made up under all circumstances to avoid disappointment at the harvest time. Adding fertilizers without any evaluation of the needs of the soil results in utilization of a small part of the fertilizers by plants while the rest is turned into insoluble form degrading soil and lowering nutrient composition of the crops. The excess of nitrogenous fertilizers causes loss of carbon from soil to maintain the C:N ratio of the soil. Also, leakage of nitrous oxide gas into atmosphere and leaching of nitrates into water streams are additional serious problems.

Since microbes are most sensitive to chemicals, use of chemical fertilizers injures or kills them disrupting the ecosystem and harming the soil ecosystem. Hence, biofertilizers (BF) are gaining more traction from farmers, also as biofertilizers act naturally to reenergize and improve the soil health.

Biochar, a charred organic matter, made by burning biomass in absence of oxygen (pyrolysis) is also finding applications as soil amendment or organic fertilizer. Although low in nutrients, it can hold nutrients that might otherwise be lost to leaching or runoff. Being a stable form of carbon lasting for thousands of years in the soil, biochar also enhances SCS. In fact, it increases growth of soil microbes like MF by providing comfortable place for them to live safely and protect OM from exposure to the air and consequent decomposition of OM releasing carbon dioxide from soil.

#### *2.6.3 Farming management*

Farming management includes strategic management of entire farming enterprise including all components like inputs, soil, crops, and livestock. Thus, it is not a typical farming practice (FP). As you cannot manage what you don't measure, defining metrics of performance and monitoring them is a good strategy. The first metric of farm productivity is defined in terms of value of farm produce and input costs. It involves maintaining periodical records of farm produce data and total costs. Total costs should include not only the cost of inputs but also the cost of labor (own family + hired) and external costs relating to environment and health of farmer/farm workers/consumers/public. Though it is too much of a non-farming task, its value is realized in the end. The top management should assimilate real value of good FPs and lay down guidelines for their adoption incentivizing good FPs. Monitoring of physical/chemical/biological tests of soil is also good strategy for sustainable soil management. Practices of mulching or cover crops are vital for soil health and fertility that lead to good crop growth. Replenishing nutrients is not the end of soil management unless food and safety needs of microbes in soil are fully met. As these tiny creatures do most of the farm work below ground while remaining out of sight, they deserve a better deal by ensuring their abundance and diversity of their community.

Selection and rotation of crops are central to crop management. Ensuring ground cover and biodiversity are sound farming practices which should find a place in the farm management strategies. Mono cropping destroys biodiversity while poly culture and rotation of crops support the ecosystem. In fact, most of the problems of weeds, pests, and diseases can disappear by ensuring biodiversity. So, instead of using harmful chemicals as pesticides/herbicides, experimenting with preventive measures should be a strategy of farming management. As animals provide multiple benefits including higher soil fertility, it makes sense to integrate livestock with farming as a biodiversity measure also.
