Another planting season has rolled around, and by the time you read this some of the crop will already be in the ground. The last two planting seasons have been generally wet, too wet in some areas. While we got reasonably normal snow cover over the winter, last fall was generally drier than normal. So far, most of the central plains has also been dry, and the showers we’ve gotten have been light. As a result, our subsoil moisture going into spring is lower than we’ve seen for a few years, and the surface moisture situation is variable, and will depend upon local showers. The forecast is also for some periods of below normal temperatures during April and May. The combination may give us some considerably different planting conditions, perhaps cooler and drier, than we have seen for a while.
During the last few, relatively wet springs, especially in areas with clayey or silty soil types, some fields got planted on the shallow side. This combined with saturated soils in June resulted in shallow rooting. For the primary and secondary root systems to develop optimally, corn needs to be planted, at least, 1 ¾ inches deep. And deeper is better than shallower. If it also happens to be cool, it can be tempting to cheat on depth, attempting to plant in the warmer soil nearer the surface. However, this usually results in the secondary root system developing too near the soil surface.
If it continues to be drier than normal, avoiding tillage is absolutely the right move. Adjusting planting depth to a consistent 1 ¾ to 2 ¼ inches will pay dividends in larger root mass and deeper root placement, resulting in more efficient water and nutrient recovery. And, if our soils are a little drier, they tend to warm more during sunny days, as there is less water to heat.
This year we have teamed up with the Mike Peterson of Orthman Mfg., looking at the effects of hybrids, strip tillage versus no tillage, and fertilizer placement on corn rooting, plant development, and performance. Mike (who was an agronomy student when I was at UN-L, so he is still young!) is a soil scientist who spent most of his career with the USDA in Colorado and Idaho. He has been digging soil pits for decades, and has spent the last few years studying corn roots in Great Plains soils. We are looking forward to working with Mike and Orthman, and will keep you posted about what we are learning to help improve corn growing technology.