Soil Health, Fertilizer Reductions, and Farm Profitability
All are possible with biologicals.
Unused fertilizer is a huge, wasted cost for growers, and with high fertilizer prices, it’s painful to know that less than half of what you apply gets into the crop. Erosion, volatilization, application at a stage when that nutrient is not in demand by the plant, soil chemistry, all play a part, as does poor soil health and structure. This unused fertilizer is either lost entirely or bound up chemically in the soil and unavailable to the plant. In a biologically healthy soil, however, microorganisms help to prevent nutrient loss and enhance absorption by the plant.
In a recent webinar, “Ask the Scientist: Soil Health, Fertilizer Reductions, and Farm Profitability,” David Stark, Ph.D., President of Agriculture at Holganix, explained how a healthy soil microbiome keeps applied nutrients near the root zone and unlocks tied-up phosphorus (P), potassium (K), and micronutrients that are already present. Soil microbes are also essential for returning nutrients to the soil from crop residue, with some types being much better at this than others.
“The nutrient use efficiency of applied fertilizer is terrible,” Stark says. “In the U.S., the fertilizer expense accounts for 36% of the cost of growing corn. Yet less than half actually benefits the crop.”
A biologically diverse soil contains bacteria, fungi, protozoa, and amoeba. Microbes enhance nutrient absorption, increase root hair formation, improve soil structure and buffer against abiotic stress. Certain microbes are especially good at breaking down the cellulose in crop residue. Unfortunately, flooding, tilling, and freezing temperatures kill many of these microbes, putting the system out of balance.
Plants and Microbes Have Mutually Beneficial Relationship
The plant secretes substances to attract the right microbes to the root, so they live within half an inch of a living root. So, we get less loss to the environment and more going to the plant. The same thing happens when nutrients are already in the soil. The microbes mine those nutrients and release them in a chemically available form.
“The microbes mine the nutrients from the soil, and in turn, the plants ‘farm’ the microbes,” Stark says. These microbes play a key role in forming roots hairs as well. As we know, the more root hairs you have, the healthier the root system is, because nutrient absorption—and the interaction with beneficial soil microbes primarily happens at the tips of these hairs.”
Stark notes that overfertilization ironically reduces the plant’s ability to absorb it from the soil.
“Too much N and P, and plants don’t farm the microbes as well,” he says. “When you apply fertilizer on a biologically active soil, the microbes eat the fertilizer, other microbes eat those microbes and spit the fertilizer back out to the plant,” Stark said. “When plants sense there is a critical mass of microbes in the soil, this triggers the root tips to start absorbing those microbes.”
Some of the microbes are absorbed completely, along with their nutrients, and others are stripped of their nutrients and expelled back into the soil. In the latter case, the microbes travel to the bud where a potential root hair can form. They secrete a hormone that induces root hair formation, then travel out the root hair and back out to the root zone.
“If you have more roots and root hairs, that means better exploration for nutrients and water, and improved nutrient-use efficiency, Stark says. “Roots also contribute 2.3 times more to stable organic matter pools than the same amount crop residue. More roots and more hairs means more soil explored and more water and nutrients into the plant.”
Holganix Bio 800+Agriculture contains an entire microbiome or community of organisms that is both abundant and diverse. It contains more than 800 species of living beneficial organisms, microbe food, and plant growth stimulants.
“Microbes unlock nutrients from residue and fertilizer applied to the soil,” Stark says. “Nutrients you’ve already paid money for. Not a speck becomes available without microbes.”
If you missed the live broadcast of this webinar, “Ask The Scientist: Soil Health, Fertilizer Reductions, and Farm Profitability” you can view the archived version online here or visit CropLife.com/webinars and check it out today.