Is there a benefit to moldboard plowing a no-till field once every 10 years? A recent article, “Changing Tillage, Changing Nutrient Management,” in the Spring 2008 issue of Plant Nutrition Today suggested that continuous no-till can lead to accumulation of phosphorus (P) at the soil surface, causing higher P concentrations in runoff.
Author Tom Bruulsema of the International Plant Nutrition Institute said this is suspected to be happening in some of the watersheds draining into Lake Erie, where the declining trend in particulate P is possibly starting to be overshadowed by a more recent trend of increasing dissolved P.
Citing recent research from Nebraska, Indiana and Ontario, Bruulsema says soils that have accumulated extremely high levels of available nutrients at the surface could see yield and water-quality benefits from plowing once in 10 years.
Following are the thoughts of several no-till industry experts on that concept:
“Instead of solving a problem by creating another, we need to solve this dissolved P problem with crop rotation or some other means. We can inject fertilizer with a fertilizer coulter instead of recommending tillage.
“The basic cause of the problem is that too much fertilizer or manure has been applied, so let’s address that problem instead? We will be causing water erosion, tillage erosion, organic-matter loss and biological-activity loss if we go back to tillage.
“I consider the disadvantages of one-time tillage much greater than any benefits. The soil tilth improvement our long-term no-tillers experience will…