The Fine Line of Soil Health
This growing season in Northeast Ohio has seen above average rainfall in May, June, and July followed by much below average rainfall in August and September according to NOAA precipitation maps. Looking across the maps Great Lakes Region there were very little zones within the “average range” this growing season. These atypical rain events have become typical in our changing environment. One way we can try to mitigate these extremes is to build our soil health. With sporadic heavy rain events we need soils with good structure and high organic matter to be able to increase the infiltration rate and catch water every chance we can get. Soils with these healthy qualities are also able to retain the moisture in the micro pores and organic matter during a drought period. Each one percent increase in soil organic matter helps soil hold 20,000 gallons more water per acre. No-till systems generally have better soil structure and according to research at the UNL Rogers Memorial Farm, it showed a much greater infiltration rate for no-till, over 4 inches per hour, than for tilled conditions, only 0.4 inches per hour, after 25 years of continuous tillage system evaluation.(1)
In addition, residue or a laid down winter cover crop will help reduce the rate of evaporation from protecting the soil from wind and sun while also reducing sheet and rill erosion before being incorporated into the soil as organic matter.
So everything will be Peachy Keen when we no-till and plant some cover crops right??? Seems too good to be true. Agronomic systems are very complex as you know.
Healthy soils also have higher microbial activity which produces water-soluble phosphorus and with higher infiltration rates that will bring more amount of water through the soil profile and possibly into tile lines and groundwater. (2)
One of the many reasons cover crops are beneficial is because they increase the depth and range of the feeding zone for the cash crops roots. However, these enhanced pathways also make nutrient (synthetic or organic) leaching more assessable to the deeper tile lines which lead to our lakes and rivers. If we can better understand our cover crop varieties and crop rotations, we can aim to have a continuous living root in our systems. It’s no secret that no-till and cover crops can be beneficial for producers however, they are don’t eliminate the potential for additional problems.