Organic Wheat Farming Improves Grain Zinc Concentration - Fig 6 HelfensteinJulian MüllerIsabel GrüterRoman BhullarGurbir MandloiLokendra PapritzAndreas SiegristMichael SchulinRainer FrossardEmmanuel 2016 <p><b>Regressions of wheat grain Zn concentration with a) grain yield, b) available P, and c) grain protein concentration.</b> Grain protein concentration had a significant interaction with cropping system on grain Zn concentration; orange shading refers to conventional. P-values for the regressions were all < 0.001 and <i>F</i>-statistics were 17.3, 14.4, and 6.60, respectively. Dotted lines (shaded area) are 95% confidence regions of the regression curves.</p>