• Plant Nutrition

5 Ways to Support Your Crop at V5

V5 corn plant.

After your corn crop has emerged, it develops rapidly, adding a leaf approximately every three days. By V5, plants have put on significant root mass, making it an ideal time to focus on plant nutrition. Consider these early-season management strategies to support your developing crop and maximize the return on your fertility investment. 

Promote Healthy Roots 

Below ground at V5, the growing root mass explores the surrounding soil to take up the vital nutrients and moisture it needs to continue its rapid development. Promoting root expansion during this time sets your crop up for more effective nutrient uptake later in the season. If Ascend2 was not applied in furrow at planting, Including an effective plant growth regulator (PGR) like  Ascend SL with herbicide or nutrient applications at V5 increases the auxin levels in a corn plant to help stimulate more rapid cell division in the roots and leaves. That not only increases the root mass but also increases the leaf area to optimize photosynthesis efficiency. To maximize the positive effects of Ascend SL PGR, it should be applied to crops with adequate crop nutrition.  

Find Hidden Plant Hungers 

The V5 growth stage is an excellent time to take tissue samples to identify nutrient deficiencies in your crop. Early-season tissue sampling allows time to plan in-season nutrient amendments if needed, but I don’t recommend taking samples any earlier than V4. To get the most accurate results, take tissue samples when the plant isn’t stressed by cold or hot weather.  

When you get the early-season tissue test report back, review the nitrogen, zinc, sulfur and potassium results with your trusted advisor. The levels of each nutrient matter but nutrient ratios are just as important. A plant needs adequate sulfur to convert nitrogen to protein in the plant. For high-yielding crops, a 10:1 ratio of nitrogen to sulfur is ideal. Potassium helps transport nitrogen in the plant. If a crop is deficient in potassium, it won’t move nitrogen to the growing point efficiently. And, without an optimal nitrogen-to-potassium ratio, plants can’t maximize kernel depth and yield. 

Prioritize Crop Nutrition 

Prioritizing crop nutrition at V5 is critical for a couple of reasons. First, the corn crop’s nutritional status at V5 often impacts the ear girth or number of rows of kernels, which is determined starting at the V7 growth stage. If there is a nutrient deficiency by V5, chances are the crop won’t recover by V7, which impacts yield potential. Second, at V5, the waxy plates on a corn leaf start to pull apart as leaves elongate. This provides an excellent opportunity to get foliar nutrients into a plant effectively and efficiently. 

Applying a foliar application of MAX-IN® Ultra ZMB® Plus fertilizer with a sidedress or herbicide application at V5 provides a corn crop with critical zinc, manganese and boron nutrients that are commonly deficient early in the season. MAX-IN Ultra ZMB fertilizer is synergistic with Ascend PGR’S, as the extra zinc helps promote auxin development and more cell division in roots and leaves. Pairing these two products helps set the crop up for season-long success.  

Fine-tune Nitrogen Placement     

Make the most of your in-season nitrogen investment by using response-to nitrogen (RTN) scores to guide placement and rates. Hybrids with a high RTN score are most likely to benefit from a split application and a higher rate than those with a lower RTN. Hybrids with a high response to nitrogen generally also have a high response to fungicides, so it’s important to plan for a fungicide application on those genetics later in the season to maximize the effect of your sidedressed nitrogen application.  

Don’t Forget About Weeds 

By the time corn reaches V5, weeds are the most crop competitive, removing water and nutrients, crowding plants and shading the sun. It’s critical that you have an effective weed control plan in place during the V5 to V7 growth stages to eliminate competition for resources and maximize your crop nutrition investment. Adding effective adjuvants to increase herbicide penetration into the crop’s canopy can enhance weed control and helps avoid costly resprays. Class Act® NG® adjuvant is a highly effective water conditioner and surfactant for use with early-season glyphosate and glufosinate applications, and it promotes fast, aggressive weed control.    

The V5 growth stage will be here before you know it, so use these tips to plan a management strategy that supports season-long success. For more information about products that are a good fit for your acres, contact your WinField United retailer.    


All photos are either the property of WinField United or used with permission.  
© 2024 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years and to be mindful of how such agronomic conditions could impact results. Ascend, Class Act, MAX IN, NG, ZMBand WinField are trademarks of WinField United.