Rebuilding Soil Fertility

What kind of soil fertility should the average farmer or grower expect to have? Most farmers have land that has been in production for many years. A sizeable portion of that land will have received at best N-P-K and S over those years. But many who make their living in agriculture tell us that in spite of new seed varieties and good management practices, their yields have either stagnated, or begun to drop. When it comes to production and/or quality, this is the case in spite of using as much or even more fertilizer than before. We have clients who sample every different type of soil in every field every year and strive to do all that the soil test indicates needs to be done. And for “high dollar” crops this may be followed by several tissue tests per year. Clients have been amazed at the increased productivity of their “good soils” after 3 years of following the recommendations for improving those soils. For yields to reach this point we find there is more to bringing them up in fertility than just adding nitrogen, phosphate and potassium. The higher the yields have been, the more this proves to be the case; soils do not have an endless supply of the required range of nutrients in a form that is available for plant use, other than what is supplied with typical N-P-K fertilization. Most growers will not be so blessed as to have soils that can be built up or restored to excellent fertility levels on the same fertilizer budget they have been using year to year. If you are working with large acreage, just expect that in the beginning it may cost you more than a “sensible” budget will allow. That is – until you verify on some of your own land that these expenditures will truly pay for themselves. If a soil fertility building program appeals to you, but you wish to limit your budget, consider sampling perhaps 10% of the acreage to learn what is shown to be needed. Do not just sample the worst 10%; that will generally be the most expensive soil to correct. Send some good soils, some average areas, and some problem soils for testing. This will give an idea of what it will take in all of these various situations, and provide an opportunity to see what nutrients are there in your better soils as compared to the poor ones. Next, determine to set aside enough of your fertilizer budget for at least a field or two, so as to follow through on the program each year for the next three years. Make the acreage large enough to buy materials in economic quantities and small enough so as not to cause economic hardship for your overall operation. It doesn’t have to be the entire acreage you tested, but it should be substantial enough to validate whether the benefits of fully implementing the program will justify the fertilizer costs.


Submitted by Rick Knot Source –