Soybean yields following cover crops and fall-applied P & K
Agronomy & Pest Management
Bill Burdine
Agronomy Specialist
Mississippi State University
Verona
Abstract
Mississippi producers spent over $254 million on fertilizer in 2017 and costs continue to rise. The cost of inorganic fertilizers makes improving nutrient efficiency in row crops a top priority in crop production. Using cover crops to improve nutrient availability to subsequent cash crops has been suggested by numerous researchers (Calegari et al., 2013; Borkert et al., 2003) however data specific to Mississippi is lacking. The effects of cover crops on P2O5 and K2O availability in Mississippi soybean systems is lacking. One study conducted across Mississippi determined soybean yields could be increased 8 to 10 bushels/acre with the addition of P2O5 or K2O when nutrient values were determined insufficient by the soil testing lab. This factorial arranged, randomized block designed study was to determine if cover crop systems would improve nutrient availability and soybean yield and if fall applied P2O5 and K2O would increase yield. A significant interaction was seen between years. In 2021, soybean yield increased when cover crops were used but in 2022, cover crops decreased yield. In 2021 and 2022, fall-applied P2O5 fertilizer increased soybean yield in no-cover and radish treatments while yields decreased in cereal rye. In 2021, fall-applied K2O increased yield in crimson clover only, whereas in 2022, fall-applied K2O increased soybean yields in all cover crop treatments. Cereal grains are believed to be beneficial to soybean production however, it may take multiple years for benefits to be realized. Further study is needed to quantify years of cover cropping before yields increase. Additional study is also needed to determine if soil moisture differences between years may be the main cause of year effect on soybean yield.
Authors: Bill Burdine
-
Bill Burdine Agronomy Specialist, Mississippi State University, Mississippi, 38879