BREAKING APICAL DOMINANCE IN SOYBEAN

Trial Overview

  • Stressing soybean plants during early growth (up to stage V4) by using tactics such as herbicide treatments, mowing, or rolling can break apical dominance and encourage branching.
  • Studies on the effectiveness of this strategy to increase yield potential have shown mixed results.1,2
 

Research Objective

  • The purpose of this study was to determine if breaking apical dominance in soybean provides a yield benefit and if so, to determine the most effective method and the most effective timing.
10;Location 10;
10;Soil Type 10;
10;Previous Crop 10;
10;Tillage Type 10;
10;Planting Date 10;
10;Harvest Date 10;
10;Potential Yield 10;
10;Planting Rate 10;
Gothenburg, NE
 
Wheat
No-till
06/06/2016
 
 
 

10; Site Notes:10;

The same 2.4 RM soybean10;product was planted in all plots.A total of six10;treatments were tested which include three common methods used to break apical10;dominance (herbicide applications of 12.5 oz/acre Cobra®, mowing with a lawn10;mower, and rolling with a lawn roller) at two different growth stages (V2 applied10;on June 22, 2016 and V4 applied on June 30, 2016).The trial was set up using a10;randomized complete block design with 6 replications.

 

 

Understanding the Results

Figure 1. Soybean Yields under the Different10;Treatments
  • Some of the treatments had higher yields than the control, but none were significantly different (Figure 1). This indicates that, statistically, the treatments were unlikely to have any effect on yield.
  • The stage of growth when the treatments were performed had no significant effect on yield.
  • Varying levels of delayed leaf senescence were observed in the treatments applied to break apical dominance compared to the untreated plots, resulting in a “checkerboard�? pattern (Figure 2).
 

What Does This Mean for Your Farm

  • Based on the results of this and other studies, breaking apical dominance in order to encourage branching likely has a limited ability to improve yield potential. 
  • These results could vary based on environmental conditions and management practices. For example, plant damage caused by mowing or rolling can increase the potential for pathogen invasion, especially in wet springs.  Significant yield differences could occur with earlier planting.