Wheat Management: Spring Green-Up

DR. ANTHONY OHMES

CHARLESTON, MO.
   If wheat tiller numbers are below target, consider applying a green up fertilizer application. Green up is typically mid-February for southeast Missouri. You have approximately a 30-day window between green-up and jointing for additional tillering. In fields with thin stands, a green-up application should be applied. However, with adequate tillering and plant development, this should be delayed until pre-jointing, Feekes 5, around mid-March.
   Specifically, in fields with less than 60 tillers per square foot at green-up, apply 30 to 40 pounds of nitrogen to increase tillering and head size. For fields with 60-80 tillers per square foot apply 20 to 30 pounds. Applying nitrogen at green up in a field with over 90 tillers can lead to a thick lush canopy which may increase the risk of disease, lodging and injury from a late cold snap. The time of greatest nitrogen uptake is between jointing (Feekes 6) and flowering. Therefore, pre-jointing applications would supply this upcoming demand and reduce plant damage from ground applicators. Research shows a yield boost by splitting applications on less nitrogen efficient sandy and clay soils. Tissue tests just before jointing can help determine nitrogen needs at jointing.
   Remember that low organic matter, usually found in sandy soils of southeast Missouri, are also prone to low sulfur conditions and sulfur fertilizers should be part of the nutrient program to prevent deficiency. Most low sulfur soils require 10 to 15 pounds per acre of sulfur.
   For more information on wheat management during stem elongation contact your local MU Extension office and ask for IPM 1022 “Management of Soft Winter Wheat”. This publication can also be found online at http://extension.missouri.edu/. ∆
   DR. ANTHONY OHMES: Agriculture Specialist, University of Missouri