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Explore the impact of pH levels and different K2O treatments on forage cation levels in alfalfa, with a focus on soil management and nutrient optimization in Wisconsin.
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Crop and Soil Management Issues Related to Forage Cation Levels J.B. Peters, K.A. Kelling, Soil Science Department University of Wisconsin - Madison
Treatments • Four K20 levels – 0, 100, 200, 400 lbs K2O/a/year* • Target pH levels • Marshfield: six levels – 4.8 - 7.3 • Spooner: five levels – 4.7 - 6.7 • Hancock: eight levels – 4.5 - 7.0 * Applied after first cutting
Average Tissue K Levels 3rd cut,1999
Effect of crushed wallboard and gypsum fertilizer on soil Ca and K levels. Arlington, WI.1
Effect of crushed wallboard and gypsum fertilizer on alfalfa tissue cation levels. Arlington, WI, 1995.
Effect of crushed wallboard and gypsum fertilizer on soil Ca and K levels. Lancaster, WI.1
Effect of crushed wallboard and gypsum fertilizer on alfalfa tissue cation levels. Lancaster, WI, 1995.
Effect of crushed wallboard and gypsum fertilizer on soil Ca and K levels. Spooner, WI.1
Effect of crushed wallboard and gypsum fertilizer on alfalfa tissue cation levels. Spooner, WI, 1996.
NIRS Concepts Reflectance Light absorption 1000 2400 Wavelength (nanometers)
Wet chemistry mineral analysis compared to NIR estimation. 3rd cut, Hancock, 1999.
Wet chemistry mineral analysis compared to NIR estimation. 3rd cut, Marshfield, 1999.
Wet chemistry mineral analysis compared to NIR estimation. 3rd cut, Spooner, 1999.
Using NIRS in Forage Testing General Recommendations General Nutrients DM yes Lignin limited CP yes Ash limited ADF yes Ca limited NDF yes P no Starch yes K no Fat yes Mg no Bypass CP yes MiroMin no Soluble CP limited ADF-CP limited NDF-CP limited
Summary Liming these acid soils was essential to optimize DM production, irregardless of K • As soil K increased, tissue K increased and tissue Ca and Mg tended to decrease • Annual applications of K resulted in a buildup of soil K and a decrease in soil test Ca and Mg
Summary, cont. • As soil Ca increased, tissue K levels tended to decrease and tissue Ca tended to increase, especially on the lighter textured soil at Spooner • Large applications of Ca resulted in a buildup of soil Ca and a decrease in soil test K
Summary, cont. • Keeping soil test K levels in the optimum range appears to be the best strategy for keeping tissue K levels in acceptable ranges for use as dairy feed