Iowa farmer Dale Launstein knows that conditions must be right to give seeds the best start and to make the most efficient use of soil fertility.
"I don't think there is necessarily a magic planting date," Launstein says. "I determine when we’re going to get our seed in the ground based on ground temperature and weather conditions. Once the ground starts heating up towards 50 degrees, we'll look at the forecast to see if we can have five good weather days to get the seed in. If it looks like it's going to cool off, we'll shut down."
Healthy, even seed germination requires adequate moisture and correct soil temperatures. And while weather may impact when fields are fertilized ahead of planting, solid early growth patterns require balanced crop nutrition to give the best start to each plant.
The last few years have thrown many growers a curveball in terms of weather patterns. From a drought in 2012 across much of the Corn Belt to a too-wet-to-plant spring last year in many states, the only constant in the weather is that it’s going to change. Moisture and temperature play a major role in the yield potential of crops, so understanding the interaction of weather and nutrients is an important step in achieving higher yields and environmental stewardship.
Moisture is essential for plant life. It is required for seed germination and plant development. When planning fertilizer applications, look at the short- and long-term weather forecast for your area. Timely and moderate rainfall can be beneficial to dissolve dry fertilizer and move nutrients into the soil rooting zone, but excessive rain can increase runoff potential and leaching potential of nutrients such as nitrate, sulfate, chloride, and boron.
Plant water availability and nutrient availability is also impacted by soil texture. Coarser textured soils do not have the water- or nutrient-holding capacity of silt loam soils. These soil types tend to dry out faster and have a higher risk for leaching, so required fertilizer should be split into 2-3 applications throughout the growing season.
In semi-arid and arid regions, irrigation programs provide a constant source of much-needed water which allows growers to regulate moisture and nutrient uptake. Nutrients such as potassium (K+) regulate water within the plant and help crops survive drought and/or drier climates. In contrast, areas that receive high rainfall amounts in short time periods or have or have subsoils with high clay content may require tile drainage to move water off the surface and out of the rooting zone in order to maintain good root and soil microbial health.
Temperature is also critical to plant physiology and nutrient uptake. It influences chemical and biological processes within the soil. Beginning with planting, temperature drives seed germination, root development, and nutrient uptake. Climates in southern regions of the U.S. warm before northern regions and allow for earlier planting dates and longer growing seasons. In contrast, northern climates may encounter cold springs that lead to slow seed germination, root and crop development, and slow nutrient uptake compared to warmer years. Warm temperatures promote rapid growth of above- and below- ground plant development, leading to root exploration for nutrient uptake.
Regardless of geography, working closely with an agronomist to achieve balanced crop nutrition is the best defense against the sudden and unexpected changes in the weather. Crops with proper nutrition are healthy and can withstand stresses incurred during the growing season.
Curt Woolfolk is a Product Development Specialist for The Mosaic Company. He leads the on-farm research and development program in North America, which includes testing Mosaic premium products, as well as new product concepts in pre-commercial stages.