163-9 Is Air-Drying of Soil Samples an Appropriate Step in Determining Plant Available Potassium for Corn?.
See more from this Division: SSSA Division: Soil Fertility & Plant NutritionSee more from this Session: M.S. Graduate Student Oral Competition: II
Monday, November 3, 2014: 3:30 PM
Long Beach Convention Center, Room 102C
Potassium (K) fertilizer recommendations are mainly based on ammonium acetate extraction of air -dried soil samples which may lead to over- or under-estimation of plant available soil K levels. On-farm trials were conducted in North Dakota and Minnesota to determine corn response to six fertilizer-K rates and the variation of soil test-K between air-dried (KDry) and field moist (KMoist) soil samples during the 2013 and 2014 growing season. Soil and tissue samples were collected at several corn growth stages and analyzed for plant-available soil K and plant K concentration. The differences between KDry and KMoist decreased exponentially as soil K increased, but increased linearly with increasing soil moisture. Fertilizer K rate increased corn yield and plant K concentration only at Ada, which had the lowest initial available soil K values of the three sites in 2013. Soil sample drying influenced the plant available soil K-test value, generally producing higher K values compared to the moist soil K method. It is unclear based on these initial experiments which method might produce a more predictable K critical value to aid in directing K application for corn in this region.
See more from this Division: SSSA Division: Soil Fertility & Plant NutritionSee more from this Session: M.S. Graduate Student Oral Competition: II
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