Seedling and Vegetative Stage Management: Key Irrigation & Fertility Tips

In preparing to plant the next crop, let’s think through the environment you’re putting your seed into.  Throughout the last 20 years, planting dates seem to have become earlier and earlier.  Seed quality and treatments have improved, allowing corn to germinate in colder and wetter conditions, up to a reasonable point.  Earlier planting dates also mean the seed may stay un-emerged longer until soil temperatures provide sufficient heat units.  This also puts the seed at risk longer for diseases, insects and drownout conditions. 

As we’ve discussed in previous articles, we want to create a “Goldilocks” environment for our newly planted corn – not too dry, not too wet, just moist enough to start germination and keep it moving along.  In semi-arid areas this can be controlled better by irrigation than in more humid areas where the farmer is more at the mercy of excessive spring rains.  Warm soil conditions also help the seed to germinate faster.  It takes approximately 100-120 growing degree units for emergence to take place.  Bare soil, whether in strips or across the field, allows solar energy to be absorbed rather than reflected off residue. 

Some farmers opt for additional nutrient sources at planting: box treatment of seed with micronutrients, in-furrow of 3-6 gallons per acre of phosphorus, dribbled UAN/ATS off the closing wheels, or 2x2 placement of 10-34-0 are all common options.  Research shows these practices tend to provide more benefit in colder conditions and/or highly calcareous soils where early season phosphorus uptake can be reduced.  Adding nutrients at or near the seed in low dosages provides a better opportunity for the plant rooting structure to access them, but they are only useful if those nutrients are limiting factors.  Tissue and soil tests will help you identify if they are likely to provide a response. 

While we think that we should provide everything the crop needs immediately before or after planting, including nitrogen, the fact is that corn generally takes up about 6-8% of its total nitrogen uptake by V6.  Granted, after V6 the nitrogen uptake rate increases dramatically, but upon emergence through the first few growth stages, plant nitrogen uptake may easily be supplied by mineralized soil nitrogen in many cases. 

Of course, from a logistics perspective, it may be easier to apply some or all of the desired nitrogen before planting, especially if heavy or wide equipment is involved.  But, we can also take advantage of the time between planting and V6 to apply the appropriate amount of nitrogen in a timely fashion, adjusting it based on early season soil-nitrogen dynamics like leaching, denitrification, and mineralization potential. 

Maintaining moist soil conditions, with water levels around the field capacity, will help make early season plant development thrive.  Excessively dry conditions of course are not desirable, but equally, excessively wet, or periods of saturated conditions as roots are developing.  This will cause roots to not go as deep to obtain water, which may be a problem later in the season if drought conditions occur.  We want our early and mid-vegetative roots to be going deeper in search of water and bringing back lost nitrates and nutrients along the way. 

While rainfed farmers primarily have tile and sometime surface drainage to help remove excess water during the spring, irrigated farmers have the benefit of adding as needed.  While it is desirable to not have to irrigate in the spring, there is that option if conditions turn excessively dry then. 

Having tools to help estimate soil moisture, as well as nitrogen, and to predict where they may go during the season, can be extremely beneficial for the farmer, whether irrigated or not.  Sentinel Ag’s tools, powered by Nave Analytics, can give valuable insights into soil nitrogen and moisture dynamics. 

Talk to Sentinel Ag directly or one of its knowledgeable account managers today to learn more.