ISSUE 14  August 27, 2009


There appears to be some interest in seeding winter wheat on prevented plant acres. It will be important to soil sample these fields prior to seeding. The residual nitrate analysis from sampling will enable a better N recommendation than assuming the levels are high due to their fallow condition. There are probably a number of fields whose residual nitrate is relatively low given the cool summer with less than normal organic matter mineralization, possible leaching of N to deeper depths and denitrification. For those growers incorporating winter wheat into their winter corn and soybean rotation, remember that seed-placed P is very important to healthy fall growth and over-wintering potential. Winter wheat usually does best when N is early spring-applied, so N application rates above those needed to provide P is not necessary. The soil test should also examine chloride levels and if these are low, about 20 lb/a of potash (KCl) should be sufficient when included in the seeding band. If there is reason to believe that S will be a problem, this should be addressed at spring top-dress application. Spring N top-dress makes some people nervous due to the questionable soil conditions in some springs, but spring mornings with frost have made these applications practical in the past.



Consider zone sampling this fall for soil testing. This method of separating areas of fields due to topography, yield maps, satellite imagery and other tools has been shown very useful in refining field N recommendations. Zone sampling is a proven method of directing soil sampling and it is used in many areas of the country to increase nutrient management efficiency. A number of resources are available to growers and consultants to explain and help them use this technology. From NDSU, a series of updated circulars are available from the NDSU Extension Service publications website (SF-1176, revised, 2008-2009, numbers 1 through 4) that explain the tools used in site-specific farming, zone development, and use of yield maps to construct yield frequency maps in addition to enviro-economic implications of the technologies. A new group called the Alliance of Site-Specific Providers formed earlier this spring consists of consultants and others that supply zone-development and site-specific farming assistance as part of their consulting and business plans. The ASSP provides a list of member contacts on their web pages that growers can use to find people nearby to help with their specific issues.

Dave Franzen
Extension Soil Specialist

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