Published on Wednesday, April 01, 2020
A late frost, saturated soils, and heavy snowfall events can truncate the tiling installation and repair season. Persistent saturated soils and accompanying hydraulic pressure in very wet years bring any weak points in drainage systems to light. Work to repair these systems ahead of planting and prioritize your most productive fields and farms for mitigation. Fields with wet or drowned out areas every year probably need different actions.
Many prevent plant (PP) acres face severe damage from heavy equipment use on overly wet soils. Farmers may have to repair ruts and soil compaction by performing multi-stage seedbed preparation in the spring; however, alleviating the “sins” of poor fall tillage with additional spring tillage is not always the answer.
The residue from the prior year’s crops, weed mats, or cover crops that were left to stand until spring and require management will slow soil warm-up and drying. Ultimately, the choice of tillage equipment and timing will be determined by spring pre-plant weather and field conditions. Vertical tillage tools offer the most versatile option to break-up the mat of plant matter. Remember to be judicious on operating depth and soil conditions at the time of tillage – you don’t want to create more compaction.
Cover crop termination shortly after spring green-up is crucial for standing cover crops with saturated soils. Spring termination should occur at least two weeks before the intended planting date to eliminate the “green bridge” that allows insects and diseases to migrate from a living cover crop to the following crop. For farmers who “plant green,” plan to use seed treatments and in-soil insecticide treatments along with follow-up scouting.
Where a cover crop, herbicide applications, or tillage were thwarted by weather, annual and perennial weeds will go to seed and build the seed bank for the coming years. A multi-site of action (SOA) pre-emergence herbicide is a must on PP acres. As the weed seed bank rebuilds, a “pound of prevention” is truly better than a “ton of cure.”
All sound nutrient management plans begin with a representative soil test for the prediction of nutrient availability to the ensuing crop. Nutrients such as nitrogen, sulfur, and boron range from mobile to very mobile in the soil and may no longer be present if they were applied the previous year. In addition, nitrogen applied to saturated soils or where water stood will be denitrified and subsequently lost to the atmosphere.
Other essential nutrients applied to the soil, such as phosphorus, copper, and zinc, should still be available in the soil if no crop was planted and removed. This also generally applies to potassium; however, potassium can be immobile under saturated and abnormally dry soil conditions. In addition, if water flowed across the PP acres it may have carried with it dissolved and suspended nutrients. Note that un-managed PP acres are not synonymous with “fallow” acres. Check your local university extension bulletins for additional nutrient recommendations related to managed PP acres or fallow acres.
Corn (and all grass crops) rely on a symbiotic relationship with mycorrhizal fungi. When a field is fallowed or PP, the next corn crop can struggle to take up nutrients, especially phosphorus, resulting in stunted, yellowed, or purpling plants – an effect called fallow syndrome. Compounding the absence of a host plant for the beneficial fungi is saturated soils driving anaerobic conditions and subsequent collapse of the biological community. Use a biological product and an in-furrow (pop-up) starter fertilizer that contains phosphorus to mediate the damage. Beneficial Rhizobia bacteria that drive the nitrogen fixation relationship with soybeans are often reduced on PP acres. Including an at-plant R. japonicum Brady inoculant is a best management practice.
Insects use cover crops and weeds for food and shelter in PP acres. Early-season insects that attack seeds and the young plant can be controlled with a broad-spectrum, seed-applied insecticide. Escalate® yield enhancement system, which is standard on Beck’s corn, soybeans, and wheat, provides early-season insect control.
Do not anticipate reduced disease pressure in PP acres. Many detrimental pathogens – whether bacterial, fungal, or viral, could be at the same or higher levels than if the intended crop had been planted. Saturated soils often reduce the populations of beneficial organisms. However, pathogens often can survive the extremes – wet, drought, and sterile soil conditions. Manage accordingly. Seed treatments that provide multi-component, broad-spectrum control for seed and seedling diseases is a best management practice.
Fields that sat fallow could face nutrient and microbe deficiencies, as well as weed problems. Cover crops need termination and management plans, and many fields need repairs from equipment and water damage. Targeted, proactive management can ensure success in fields that were PP or fallow in the previous season.
Author: Mike Blaine
Categories: Agronomy, Agronomy Talk