The idea of biological farming is to focus on whole ecosystems, particularly the soil environment, rather than just the above ground plant environment. The farmer must encompass air, water, soil, plants, and all organisms into his or her farming practices. The objective is to stimulate biological activity in the soil and use natural organisms as our fertilizers, pesticides, and herbicides. These microorganisms in the soil are the key to our survival as a species.
Beneficial microbes have numerous benefits to plant growth. These microbes can attach to large minerals and break them down into smaller pieces for the plant to absorb. They can also increase nutrient efficiency of the plant by providing the right nutrients at the right time during growth. This leads to increase plant vigor and growth increasing yields and germplasm.
Soil microbes can also decompose soil organic matter (SOM) to release minerals and nutrients into the soil over a long period of time. This forms an enhanced soil structure that gives rise to numerous pore spaces to be occupied by air and water. Collectively, these effects will transfer and replicate into the natural environment allowing the land to heal. To begin biological farming, soil amendments must be added to kick-start the biological activity.
These soil amendments are organic in origin. That is, they are free from synthetics and are completely natural. This includes green manure, brown manure, kelp, compost, and worms (castings too), just to name a few. These materials provide inoculants of microbes (compost and worms) and nutrients (kelp, manures) to begin the process. Each farm will have different requirements based on farm history, soil quality, crop choice, local weather, etc., but all can benefit from this step.
The key to success is to cease all, or in some cases nearly all, farmicide use (pesticide, herbicide, etc.). Farmicides kill their target, but they also kill beneficial microbes in the soil. Adding soil amendments and halting farmicide use will allow beneficial microbes such as mycorrhizae and rhizobia to repopulate the land.
Mycorrhizae are beneficial fungi that increase plant growth by supplying nutrients to the plant in exchange for sugars. Mycorrhizae form a fibrous network of hyphae to collect water and nutrients that are away from the plant roots. This helps to increase plant growth and reduce the need for direct fertilization.
These fungi also create symbiotic relationships with specific plant species to perform this exchange of nutrients. Mycorrhizae have been shown to have strong positive influence on plant growth, yield, and vigor. Another well-understood symbiosis is with plants and rhizobia.
Rhizobia are bacterial organisms responsible for nitrogen fixation in soils. These bacteria convert nitrogen gas into a usable form of organic nitrogen for other organisms. Rhizobia form nodules on plant roots, which contain Rhizobium bacteriods. This is where nitrogen fixation takes place.
Nitrogen fixation is an incredibly energy and resource intensive process for us and yet these bacteria do it for a few sugar molecules. Available nitrogen is often a major limiting factor in agriculture operations where climate and water are in sufficient quality and quantity. This is the largest benefit and it is well studied and established. However, there are more advantages when an entire microbial community is created and allowed to thrive.
Maintaining a healthy population of soil microbes allows organic material to continue through the entire recycling process creating a reservoir of nutrients. These nutrients are slowly released by decomposing bacteria and fungi (previously killed by fungicides) present in the soil. Other soil organisms will transport heavy metals to the plant, which can be important for normal plant growth or soil remediation. Adding SOM to a soil provides the necessary elements for a healthy microbial community.
With SOM, microbes can break down large particles into smaller, soluble forms required for plant absorption. SOM also adds carbon to the soil. This improves the soil structure as well as promotes the growth of additional microbes. A soil with high SOM has a healthy microbial community, which then assists the plants in the uptake of various nutrients.
Today's farming operations increasingly rely on inputs of fertilizer and farmicides and unfortunately, those inputs are becoming more expensive and are required in higher doses. Utilizing soil microbes to enhance nutrient efficiency in the field will not only reduce production costs, but will produce healthier plants and a healthier crop. These microbes have the ability to seek out specific nutrients required during various plant growth stages.
Supplying the right amount of nutrients at the proper time allows the plant grow fast while still maintaining a healthy, natural vigor. Plants can grow extremely fast when fed a high nitrogen fertilizer. However a high nitrogen environment can block the uptake of other nutrients, weakening the plant overall. The plant cannot keep up its defenses during this rapid growth and thus farmicides are applied.
Applying high nitrogen fertilizers also changes the pH of the soil. This also affects the plants' ability to take up a balanced supply of nutrients. Thankfully there is a solution. A healthy population of microbes can solve this problem.
As soil organic matter (SOM) and microbe populations begin to increase in a given soil, the pH of that soil will gradually equilibrate to around 6.5. This is significant because a soil with a pH of 6.5 – 7 provides optimum nutrient availability for the plant. Coincidently, this is also the optimum pH for soil microbial activity.
So the microbes (and the farmer) have twice the incentive to balance soil pH. The microbes do it because it promotes plant growth. Strong and healthy plants supply plenty of food for the microbes. As all of these changes begin to fall into place, natural disease suppression rises and pests no longer become a major issue.
Once the farmer has ceased farmicide applications, beneficial microbes not only invade the soil, but also aerial portions of the plant as well. Research has shown that healthy plants can have a minimum of 60% of their leaf area covered in fungi and bacteria! These microbes create a physical and chemical barrier on the leaf the same way soil microbes do.
Soil microbes have a variety of tactics they use to prevent disease in their nurturing plant. Soil microbes can prevent disease by excreting chemicals or creating a physical barrier around the root. Again, it is their life at stake if the plant becomes infected and can no longer provide sugars.
Biological farming also helps to improve the soil structure leading to increased soil water retention. A biologically active soil creates pores for which to store organic matter. This is generated by root expansion and microbial growth. As the plant roots grow and enlarge, die, and shrivel, they leave behind pore spaces that are used to hold air and water. Microbes also create humus: highly nutritious, highly porous, carbon-rich organic matter.
Humus is very porous and can hold a lot of water. As soils become more enriched with SOM, humus will develop from the microbial activity. This allows the soil to retain much more water than industrial agriculture. Not only will higher water retention save on irrigation requirements, but it can also allow a crop to survive drought conditions. Soils with larger water capacity have the ability to continually supply water well beyond their industrial counterparts.
All of this biological activity also increases soil carbon. Soil carbon benefits microbial communities, traps CO2 from the air, and helps clean water as it moves to the water table. Plant material and sugars fed to microbes are two ways carbon is easily stored in the soil under biological farming. This can effectively remove carbon from the atmosphere and offset the use of mechanical equipment on the farm. Biological farming is the key to a successful agriculture and a healthy planet.
As we must not forget through all this that microbes have populations . There can be high populations such as those found in established biological and organic operations, or they can be low such as those found in industrial agriculture. Varying degrees of biological activity can render diverse harvests across neighboring fields.
Any comparison between organic farming and industrial farming needs to include microorganism population counts. Bringing this statistic into the world of management would give scientists and farmers a basis for which to measure, and manage. Then, we can begin understanding really how much microorganisms can impact our agriculture and change our future.