By James Hoorman, Hoorman Soil Health Services, adapted from an article in Acres and an article by John Kempf
Fast seed germination is critical for getting crops off to a good start and to achieving higher crop yields. Cold wet weather often causes early crop stress that can be difficult for the plant to overcome and may cause yield losses long-term. Fast seed emergence has many advantages.
First, the seed generally has enough energy to get the roots established and a leaf growing to capture the sun’s energy. When seed roots emerge quickly though, there is less time for seed damage by insects, especially seed corn maggots, wireworms, and root worm larva. Fast growing plants can outrun most slug damage or flea beetle which feast on sickly plants that are struggling to grow quickly. New growing roots supplement seed nutrient reserves to improve plant growth, especially from micro-nutrients needed to speed up plant growth. When seeds germinate slowly or the seed is of poor quality, none of these benefits occur.
Often, seed planting occurs when crop and field conditions may not be perfect. Sometimes waiting until the soil warms up can greatly improve fast seed emergence and result in less insect and disease problems. However, the weather does not always cooperate and when farmers have many fields and acres to plant, sometimes seeds are planted under less-than-ideal soil conditions.
Getting a fast seed emergence starts with purchasing high quality seed. High seed quality depends upon many conditions including how the crop was grown the year before and also how the seed is stored. Starting with poor quality seed can make it difficult for a seed to emerge quickly. While most seed will germinate under ideal moisture and temperature conditions, seeds that germinate slowly in 5-7 days or even 10 days create plants that may struggle to produce high yields. The nutrients inside the seed need to be balanced for fast emergence along with the nutrients in the starter fertilizer. High salty fertilizer and high concentrations of fungicide and insecticides may disrupt beneficial microbial populations that help germinating roots grow quickly.
Good seed should have a high-test weight and be high in crop nutrients including protein, carbohydrates and fats. Good seed should have a healthy microbial population on the seed surface to colonizes germinating roots and emerging leaves. Healthy microbial populations keep root diseases in check. Without a healthy microbial population, the seed has to produce extra root exudates to entice soil microbes to protect the plant and to feed it. Healthy seed with a healthy microbial network can grow faster than a seedling trying to establish a new microbial network. This process can take several weeks, allowing crop diseases like fusarium, rhizoctonia, pythium, anthracnose, phytophthora and many other root-rot diseases to cause crop damage. Healthy seeds with healthy microbes grow much quicker, allowing seedlings to outrun both disease and insect damage.
Beneficial bacteria are referred to as PGPRs or plant growth promoting rhizobacteria. These bacteria produce phytohormones that influence plant growth and development, particularly root branching. Microbial seed treatments or inoculants produce larger seedling roots. These larger roots help plants produce a larger crop yield by supplying extra nutrients when the plant is filling grain. PGPRs also contribute to larger stem size and a larger internal vascular system to supply more nutrients for larger crop yields. Plants may have the genetics to produce larger yields, but without a larger pipeline or nutrient flow within the plant, yields can be limited by a lack of water and nutrient flow. Increasing plant growth and faster germination is one key to getting higher crop yields.
How can a farmer take advantage of this information. First, purchase high quality seed that has a high-test weight. Check the seeds per pound. Small seeds may not have enough plant nutrient reserves or vigor to germinate quickly. Before planting, plant a few seeds in a clear plastic cup to see how quickly they germinate and how fast the roots reach the cup walls. If possible, enhance seed with microbial stimulates or inoculants. All seeds have beneficial microbes living inside the seed, but over time, these microbial populations may be reduced or lost. Adding microbial inoculants (PGPR bacteria, mycorrhizae fungi) may reinvigorate the seed along with adequate and balanced fertilizer nutrients that are not too salty. Seeds that have good levels of manganese, zinc, copper and boron will germinate much more quickly than those without. Adding trace minerals and beneficial inoculants is becoming more common as farmers recognize the benefits of beneficial microbes to improving soil and plant health. Getting that crop off to a great start may be one of the keys to getting much higher crop yields.