April showers may bring erosion

     This past winter has given farmers a very good look at the risks involved with any kind of fall tillage. All farmers know that rainfall on frozen ground can cause soil loss. This past winter, eastern Iowa had two of these events. The first rain in December involved only a 0.2-inch rainfall across Jones County, and caused almost no soil loss and water pollution. Heavy rain totals in counties to our north and west caused some severe loss!

     In early February, Jones County was not so fortunate. Over an inch of rain fell over a 36-hour period. It was very apparent in fields that had had tillage, soil was moving. The water that was running off of tilled fields was brown. The water runoff from adjacent not tilled fields was clear!

     Can row-crop farmers eliminate the risk of soil loss from a heavy rain event? Not ever completely. Soil on harvested soybean fields will always be vulnerable until about the middle of June in the following summer, when young corn plants can offer some soil protection. No-till planting of soybeans, grassed waterways, and never tilling any steep slopes are the easiest conservation steps to take in situations where tillage is necessary, such as manure injection.

     Another more costly measure of soil protection is, of course, cover crops! It is costly in terms of both field application expense and time constraints during a busy fall harvest season. Short-term pay back is variable and difficult to measure. Fortunately, our land-grant universities are making a tremendous effort to put some metrics to the benefits of cover crops and no-till. Strip trials over many years comparing no-till, cover crops, combinations, and conventional are being studied. Long term benefits are being unquestionably proven. Most aspects of soil health, from tilth to organic matter, have been improved.

     We do know that healthy soils can produce high yields with less fertilizer expense. Timeliness of nitrogen availability is critical to obtaining optimum corn yields. No farmer wants regulations like those imposed on the Chesapeake Bay watershed. But the data from the state of Maryland over the last 20 years shows that the corn yields have steadily increased while the total tonnage of nitrogen applied has been significantly decreased. The science of strategic N placement is irrefutable. Our universities and commodity organizations studies and tests are proving that profitability and conservation can go hand-in-hand.

     The Jones SWCD works with state, federal and private partners to improve water quality, soil conservation and wildlife habitat on private and public lands.

     For more information, stop by our office in the USDA Service Center at 300 Chamber Drive in Anamosa, visit us at www.jonesswcd.org, or give us a call at 319-462-3196, ext. 3.