A conservation planning should be part of every Iowa farm management plan. Now is the best time to conduct an annual review of the effectiveness of conservation plans, based on field observations and the outcomes seen during the 2003 growing season. Residue management, soil erosion control, improved water quality, soil productivity and moisture conservation and its impact on yield can be used to measure success of your plan.
The dry conditions experienced this season were a test of sound conservation planning, since residue cover, conservation practices, and resultant moisture conditions may have had an impact on productivity.
This season's moisture conditions may also require special attention and consideration in planning for next year.. From low levels of existing residue to the need for additional livestock forages (because of depleted pasture reserves), any decisions made for short-term benefit still need to protect the soil.
Here are some issues to consider when planning for the 2004 crop year.
Residue management
Baling stalks and stubble is a tempting, and sometimes necessary, choice in livestock operations. However, even the best baling strategies will put crop residue targets -- at least 30 percent residue on the field at planting time -- at risk. This percentage is the minimum requirement to meet a sound conservation plan.
Keep several considerations in mind when justifying stalk baling. First, evaluate the residue density and the quality of the residue prior to baling. Second, leave a good stand of stalks to help trap snow during the winter season. Third, evaluate the residue distribution across the field before considering baling. Finally, don't remove residue from highly sloped areas. If stalks must be harvested consider raising the baler pick-up or leaving unharvested strips across the direction of prevailing water flow or wind.
Tillage
Producers who want to establish the goal of 30 percent residue at planting time next year probably should not go to the field this fall with a tillage implement, particularly into soybean residue.
Performing a primary tillage operation increases surface roughness and usually requires a secondary tillage operation to level the soil for planting. These two tillage operations alone will dramatically reduce the amount of residue left at planting. Before making the decision to till, make certain there is a valid reason -- with specific and measurable benefits -- to do so.
One of the more common reasons to till is to break up soil compaction with rippers. However, under the current soil moisture conditions, it is difficult to determine if you have soil compaction. The best time to measure soil compaction is when the soil moisture at field capacity. Also, ripping may allow unwanted soil moisture loss.
Nutrient management is another important component, particularly following a dry season where yields were generally lower than normal. There may be significant residual amounts of nutrients left in the soil, especially for P and K.
Residual P and K need to be accounted for in next season's fertilizer applications, whether from a commercial or manure source. The reduction of P input, along with residue and tillage planning, is a complete approach for achieving a sound conservation plan that meets the environmental and economic goals of your operation.
Soil testing can help achieve a balanced nutrient management plan that helps determine crop nutrients needs and helps producers settle on application rates for commercial fertilizer, lime, or manure.
Conclusion
As Iowa producers start to make decisions- for the 2004 growing season, it is critical to reflect and evaluate the outcomes of the previous season during the conservation planning process. Observations of yield performance, residue cover, and soil conditions should be guiding principles that minimize the potential impact of similar repeated conditions.
Conservation tillage and no-till are great systems and have a positive impact on soil productivity and profitability, no matter what the weather does. These systems improve soil tilth and soil organic matter, and can reduce the costs associated with the tillage equipment and field operations used in conventional tillage.
Many conservation decisions made now can affect soil erosion over the next several years. Use the time after harvest to gather information and make sound decisions about conservation.
Funding support provided by USDA Natural Resource Conservation Service through Cooperative Agreement No. 74-6114-10-03.
This article originally appeared on pages 174-175 of the IC-490(23) -- October 20, 2003 issue.