Nutrient stratification in direct seeding has been talked a lot about this past year or so. Stratification refers to a non-uniform distribution of nutrients with depth. Most of the concerns appear to be with concentrations of nutrients near the soil surface in direct seeding, hence the term stranded. The concern is that our direct seeding systems place seed and fertilizers at fairly shallow depths and that plants will not be able to access these nutrient or will have an inadequate supply, especially during dry times. How do you correct this problem or do you even need to try?

Native soils are quite stratified and native plants seem to do quite well. Our annually cropped fields are fairly stratified too. However there does not seem to be evidence to date that our crops are suffering because of this situation. Matt Hagny in his presentation on Levering Biology  at Direct Seeding Advantage 2006 stated that that he did not consider it a problem. A recent article "Nutrient Stratification in No-till Soils", written by three soil scientists in the USA took an in depth look at stratification in no-till. Their conclusion was that its best thought of as normal and repeated attempts to correct it will not be profitable. To read a brief summary of their article click on the pdf. The complete article can be purchased online.