Managing your soil moisture bank

After an early start to harvest most farmers found themselves waiting for the rain to quit.  What can a producer do to be productive? How about planning a cover crop planting?  It really is never too late to plant a cover crop!

The plentiful to excess autumn rainfall amounts highlight another benefit that cover crops will provide, which is using excess water.  Why is that important right now you may ask?  As our soil moisture profile fills during this post-harvest time frame it leaves less room in the “soil moisture bank” for storing off-season precipitation.

Managing the soil moisture bank becomes even more important going into the spring when we typically receive heavier rainfall amounts and there is no crop growing to use the moisture.  The risk in this scenario is that when excess rainfall percolates through the root zone and out of the reach of crop roots, it takes crop nutrients with it.  You may have spread fertilizer in the fall as part of your fertility program and not end up getting the value out of it.

Getting the jump on establishing another living root system in the soil before next year’s cash crop is planted is a big benefit as well.   Mycorrhizal fungi depend on living roots exuding plant sugars for their survival.  These fungi are important players in the soil biology, living in and around plant roots and providing water and plant nutrients from the surrounding soil in exchange for the liquid carbon in released plant sugars.

A “mycorrhizal handshake” occurs when the cash crop seed germinates into a soil with the mycorrhizal fungal system already growing in it.  The mycorrhizae colonize the growing seed and protect it from pathogenic fungi in the soil.  The plant recognizes the mycorrhizal fungi as beneficial and begin to funnel carbon in the form of plant sugars to it to encourage their symbiotic relationship.

Another benefit is weed suppression provided by the cover crop early in the season.  We have all heard the saying “The best herbicide is plant canopy”.  Cover crops get an early fall start and take off growing again as soon as soil temps get to a little as 35 degrees in the spring.  Save some money on herbicide…spend it on cover crops.

Anyone who chose to aerially seed or broadcast into standing cropland this fall is likely very pleased with their results as the cool and wet conditions have really favored good growth.  The cover crop will be using some of the excess moisture, helping to dry the soil out and provide a more trafficable field condition for harvesting.  Earlier seeding makes the use of multi-species mixes more effective as the sunlight and growing degrees available decline rapidly in the fall.

What can you plan to do now?  Get your crops harvested and hit the field with a drill as soon as you can.  The later start in the fall can be managed by letting the covers grow a little longer in the spring.  Plant your crops into the living cover crop, a process called “planting green” and let both the cover and cash crop grow at the same time for a period of time.  That period will be determined mostly by soil moisture usage by the two.  This is how you manage your soil moisture bank.

At the end of the day, a field planted to a cover crop planting will always enjoy an added level of protection from sheet and rill erosion and gully erosion.  Look at it as an insurance policy for your land as well as your purchased and applied inputs. 

The Lower Elkhorn Natural Resources District and USDA-NRCS offer some attractive financial incentives for trying cover crops on your farm.  Stop in or call them for more information on one of the latest and greatest beneficial soil conservation practices.

Marty Marx from Wayne aerially applied a multi-species cover crop with a helicopter seeding service August 31. Benefitting from Mother Nature’s plentiful rainfall, the cover crops surface-germinated and are set to provide a wide range of benefits from soil erosion prevention and regenerating his cropland soils to managing his soil moisture bank. The jump start the cover crops get also allow them to sequester unused crop nutrients, provide a mycorrhizal environment for the germinating seeds and early season weed suppression.