Update:
Field Sites: Accomplishments September 2020:
Studies were established at 4 locations during 2020 with focus on K deficient soils, but also including a location with traditionally high K level. Soybean growth was generally at optimum condition for most locations with potential for good yields, and visual response to K fertilization. Soil samples were collected from each individual plots before treatment application, and sent for analysis including chemical, physical and biological tests. Soybean plan tissue was also collected al all locations and preliminary results are currently under statistical analysis.
Methods for soil test K are currently under analysis, including traditional K test, analysis on moist samples, and in-season ion-exchange resin as indicator K supply during the growing season. Clay analysis is also ongoing for current field study locations, and additional samples will be collected to across soybean producing regions to evaluate the predominant clay species and correlation to K supply.
In season soil moisture and temperature was monitored at all locations during 2020, as well as the evaluation of in-season soil K (Figure 1, Table 1) (look attached file). These results will be evaluated in the context soybean K uptake and availability for the growing season.
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