• Soil microbes & crop fertility: the missing link?

    Soil microbes & crop fertility: the missing link?

    Craig Dick, Director of Wholesale at Midwestern BioAg, explains how soil microbes hold the key to organic matter formation and enhanced nutrient retention and efficiency.

    Industry Voice by Midwestern BioAg |

    May 01, 2017

    When formulating a fertility plan, growers take many factors into consideration. These may include crop removal, soil tests, yield goals, cropping rotations and more. The process can be complex, especially since some of the largest impacts on crop performance – weather and soil health – are challenging to manage, at best. What recent soil science has taught us, however, is that soil health is a key driver of fertility and profitability. While growers cannot plan for floods or drought, good soil management can help all farms improve soil health, nutrient efficiency and plant uptake.

    Fertilizer Solubility & Availability
    In most states, NPK crop fertilizers are labeled using the percentage of total available nutrients in blends. This is the percentage of applied nutrients that are water-soluble, and immediately plant-available, upon application. Soluble nutrients are necessary to support early crop growth and yield potential, but additional nutrients are also needed throughout the season to

    maximize crop yield potential.

    “When we apply nutrients in soluble forms to the soil, the risk of nutrient loss and leaching increases,” said Craig Dick, Director of Wholesale at Midwestern BioAg. “However, what we’ve learned is that soil management with a focus on improving soil life and structure can help us capture more applied nutrients and boost profitability.”

    When fields are managed for optimal soil conditions, soil porosity and aggregation improve. These are the conditions that allow beneficial soil life to flourish. “Deep tillage and harsh crop inputs can damage soil life,” said Dick. “When this occurs, we miss the opportunity to use soil microbes to our benefit.”

    Soil Organic Matter: Your Nutrient Bank
    Soils are often rich with nutrients stored within soil organic matter (SOM). Other nutrients can be bound to soil calcium, aluminum or iron, unavailable for plant uptake. Unlike soluble nutrients listed on fertilizer tags, these nutrients are not accessible to plants. However, when soil conditions allow for thriving microbial populations, microbes can cycle nutrients from organic matter into plant-available forms and release nutrients that are chemically bound within the soil.

    “Think of soil organic matter as your farm’s nutrient bank,” said Dick. “Just like how bank tellers can deposit a personal check and return with cash, soil microbes can turn organic matter deposits into plant-available nutrients. Banks are only as good as their systems and staff. Soil works much the same way.”

    Emerging Research Suggests Microbes Build Soil Organic Matter
    It’s well understood that when present, soil microbes break down SOM and release valuable crop nutrients. However, emerging research indicates that the relationship between SOM and microbes may be more complex than previously thought. “Established soil science suggests soil organic matter is formed from decaying plants and residues,” said Dick. “However, recent findings from the University of New Hampshire show organic matter is formed as microbes breakdown plant residues – not directly formed from plants residues themselves.”

    In the study, soil microbes generated SOM in the absence of plant residues. Even when fed only table sugar, SOM created by microbes was nearly identical to naturally formed SOM from the field.

    “This research may revolutionize how farmers build organic matter, and stored nutrients, in their soils,” said Dick. “However, many of the same management practices that build organic matter also support soil life. When we focus on preserving and rebuilding soils through reduced tillage and careful input selection, healthy soils will follow.”

    Research will continue to build on the industry’s understanding of soil health, but the benefits of healthy soils remain the same. When soils are managed for optimal soil conditions, growers can optimize SOM formation, crop yields and plant resiliency.

    Source: http://www.wallacesfarmer.com/soil-health/soil-microbes-crop-fertility-missing-link#!/

  • Nitrogen Application

     

  • Corn, Soybean Planting Considerations For This Week’s Cold Snap

    With this week’s forecasted low temperatures projected to dip into the high 30s (°F) with potential rain events, growers have asked if/how germination will be affected for corn and soybean planted this week.
    Summary
    Imbibitional (fast) water uptake occurs within the first 48 hours after a seed is planted. Once planted, corn seeds need a two-day (48-hour) window and soybeans need at least a 24-hour window when the soil temperature at planting depth does not drop much below 50°F.  When the soil temperature drops much lower than 50°F within that time frame, there is potential for chilling injury to affect seed germination and seedling growth. Soil temperature decreases after this time are less likely to affect seed germination.
    Key Considerations
    Check the weather forecast and soil temperatures for your area. It’s also important to check the soil temperature of each field the morning you intend to plant. (This can be done with a meat thermometer.)
    Second, check on your seed tag or with your seed dealer regarding the cold tolerance of your corn hybrids/soybean varieties. Hybrids and varieties vary in cold tolerance and company rating scales differ. However, be aware that imbibitional chilling is a physical phenomenon that can override genetics.
    An inexpensive meat thermometer is being used to check soil temperature in an individual field. 
    Cold Stress in Corn
    When corn seeds imbibe (take up) water, cell membranes stretch and cells expand. When a damaged cell membrane rehydrates, it may not return to its normal shape and size. This can create a “leaky” cell. Water is at its densest at about 39°F so when cold water is imbibed, it may result in additional membrane damage. These ruptured membranes may occur in the cell walls and in the mitochondria. In the plant this action may disrupt the embryo/endosperm enzymatic conversion to energy, but mostly results in leakage of cell solutes and sugars. This, in turn, is likely to reduce growth rate and interfere with growth of the emerging seedling.
    • Debate exists about what specific temperature and timing causes imbibitional chilling.  However, corn plants that imbibe cold water (in the low 40s) in the first 48 hours after planting undoubtedly are affected.
    • Planting when soil temperatures are above 50°F alleviates concerns of imbibitional chilling affecting corn emergence. Some scientists suggest that corn will not be injured at soil temperatures as low as 41°F; however, there is certainly some risk of injury from imbibitional chilling at those low temperatures.
    • For best results, begin planting corn when soil temperatures are in the high 40s and the short-term forecast calls for warm days that will continue pushing soil temperatures higher. If soil temperatures are in the high 40s and the weather forecast calls for cold wet conditions within the next 48 hours, soil temperatures will likely drop and planting should be delayed until temperatures warm.
    Cold Stress in Soybean
    Soybean germination consists first of a very fast uptake of water (imbibitional phase) followed by a much slower uptake of water (osmotic phase). Chilling during the first phase can cause severe problems because the imbibed water is needed to rehydrate the cotyledons and embryo to the point that cell membranes become functional. Cold temperatures interfere with proper hydration of those membranes.
    • The imbibitional phase is typically not very long (usually less than 24 hours) and can occur with relatively little soil moisture since the seed is dry at planting. Thus, getting a cold rain within 24 hours after planting can lead to soybean chilling injury and thus lower stands.
    • Chilling injury is likely greater if soil temperatures were cold (less than 50° F) at planting rather than becoming cold 24 or more hours after sowing. Chilling injury occurs with temperatures of less than 50°F within 24 hours of planting; germination failure and seedling death occur at soil temperatures around 40°F. The longer the seed is in the ground at warm soil temperatures before cold temperatures occur, the less chance there is for chilling injury.
    • Saturated soil with cold temperatures significantly reduces germination rate, thus fungicide seed treatments are recommended if planting in April or early May.
    • Bottom line: Plant your soybeans if you think the soil temperatures won’t get cold (less than 50°F) for at least 24 hours. If you planted two or more days before the cold rain, there should be no imbibitional injury due to cold temperature.

    During the second phase of germination, the fully functional membranes (after imbibitional hydration) create an osmotic situation in which water diffuses into the living cells. Osmotic water uptake is slow with cold temperatures. Chilling during this phase causes little direct injury to the germinating seedling. Cold temperatures will, however, slow emergence.

    In conclusion, check the weather forecast, soil temperature, and hybrid/variety cold tolerance before planting.  The first 24- and 48-hour periods are critical for soybean and corn, respectively, if soil temperatures dip much below 50°F.  Monitor your fields based on planting date throughout the year to determine any affects on plant stand and yield.