Corn Earleaf Tissue Analysis: Is It Useful in Arkansas?.

The University of Arkansas Corn (Zea mays L.) Verification Program is used to demonstrate the accuracy and benefits of following Land-grant University recommendations. These field-scale demonstations couple extension personnel with producers to manage fields in strict accordance to University of Arkansas corn production guidelines. Fertilizers represent the largest single input cost for Arkansas corn producers and can exceed 25% of their total production costs. Earleaf tissue samples were collected at the R1 (greensilk) growth stage to verify the accuracy of the soil fertility and fertiliztion progam and determine if current recommendations provide sufficient plant nutrients at this critical growth stage to maximize corn yield. Each field was divided into 10 equal grids and a mnimum of 20 earleafs were collected from each section. Samples were dried, ground and analyzed for plant essential nutrients. For the seven fields sampled in 2015 there were only two fields that reported nutrient levels in the deficient category, which were for Zn. Most of the fields sampled fell within the acceptable range for plant nutrient concentrations at the R1 growth stage, with only a few reported "low" levels for either N, Mg, S or Zn. Results indicate that current fertility recommendations in Arkansas provide nutrient levels that are adequate for optimal corn growth at the R1 growth stage. However, these data also provide valuable insight as to where future directions of the University of Arkansas soil fertility program should focus their efforts in regards to corn as more soils and tissue samples are reporting low or defieicnt levels of Mg, S and Zn.