Listen to the KTIC Radio Extension Corner: Finding Profit in 2016 with lime
This is Dr. Nathan Mueller, your local agronomist with Nebraska Extension. Finding profit in 2016 is something we are all focused on. Seed, fertilizer, and chemical usually make up 30-40% of your production costs. Last time we talked about taking a good soil sample. Now we can talk about which values on our soil test results we need to deal with. So let’s answer 4 basic questions about managing soil pH for profitability this morning.
First, what is the optimum soil pH? Between a pH of 6.0 and 6.5 in the top 6 to 8 inches is optimum. Research in Dodge and Washington Counties has shown significant corn and soybean yield responses to lime application when soil pH drops to a pH 5.5 or less. Yield responses to lime application ranged from 2 to 13 bushels per acre for soybeans and 2 to 14 bushels per acre for corn in the years following the lime application.
Second, is there situation were low soil pH is more commonly observed? Soil acidity is generally more of a problem on dryland fields than irrigated fields. Irrigation water often contains enough carbonates to help reduce soil acidification over time. So, don’t ignore the fact that your dryland corners might need lime sooner. When only dryland corners need lime, consider the cost and convenience of pell lime versus ag lime in this situation.
Third, do I need to incorporate my lime? No, on-farm research in Dodge County has shown no yield advantage to incorporating lime. Lime application increased yields at low soil pH regardless of incorporation. Additional research in the region has shown lime can move 0.5 inches per year down into the soil and react. Soil pH in the top 3 to 4 inches can be managed without incorporation.
Lastly, since I don’t plan to incorporate my lime, should I reduce the application rate? Yes, reduce the rate by half compare to what you would apply based on the 6 to 8 inch depth. For two reasons. First, we know that we can manage the top 3 to 4 inches without incorporation. Second, high rates of unincorporated lime on the soil surface could increase the chance of herbicide carryover, such as atrazine into soybeans.
For more information about managing your soil pH, visit our local website at croptechcafe.org. Know your crop, know your tech, know your bottom line. This is Dr. Nathan Mueller, your local agronomist for Nebraska Extension on KTIC radio.