Episode 26 of Battle for the Belt is now available:
https://www.youtube.com/watch?v=OZbj49llizU
In Episode 26, Dr. Osler Ortez, Extension State Specialist for Corn Production, is in the field demonstrating methods to test corn stalk strength as we approach harvest.
The dry conditions throughout Ohio has pushed harvest to earlier dates this season. One of end-of-season consideration, especially under drought conditions, is stalk strength.
Stalk lodging can be the result of a few factors interacting. Dry conditions during the reproductive stages can cause the plant to mobilize carbohydrates from stalks and leaves to the ear. This leads to weakened stalks and depleted leaves. Another cause of stalk lodging can be stalk rot development. The stalk rots can be caused by one or more fungi that are capable of colonizing and disintegrating the inner parts of the stalk. The extent to which the fungi affect the plant is plant health dependent. If the plant is healthy, it is more resilient to the damage caused by the fungi, however, if the overall health of the plant is low, then the fungi can cause more damage.
There are a few methods that can be used to asses stalk quality:.
- Splitting Stalks: The corn plant is cut at the base or crown of the stalk, then using a knife to split the stalk in half. A healthy stalk will look clean with a consistent white color, and the spaces inside the stalk are fully occupied. A diseased stalk will have gaps that are not filled and are disintegrating, there is also discoloration present (Figure 1).
- Push-test. Grab a plant at the ear level and push toward the opposite row (or away from you). If the stalk does not crack or break off, that suggests that there is good stalk integrity. This shows the stalk status up to that point. Be mindful that stalk integrity may change later on, and re-assessing at a later period can be necessary.
- Squeeze-test. For this method, take two fingers and squeeze the stalk between nodes or at the node in the lower portion of the plant. If the stalk does not compress when squeezed, that suggests that there is a lower chance of lodging. While a stalk that compresses together when squeezed, suggests lower stalk integrity (Figure 2), and more chances of lodging.
If stalk integrity is low, nothing can be done in-season to fix it; however, we can plan proactively and make decisions that will minimize the effect of lodging on harvest loss. Prioritizing fields with stalk integrity issues for early harvest will assist in preventing lodging, ears dropping, and losing ears to the ground. Wind storms can worsened these issues, consider wind and storms coming through when prioritizing fields that have compromised stalk integrity.
Besides prioritizing harvesting fields that have stalk integrity issues, there is another management practice to consider, which is hybrid selection. The Ohio Corn Performance Test has been evaluating hybrids since 1972. The corn performance trials look at >100 commercially available hybrids every year at 9-11 different locations throughout the state. In the 1970s, stalk lodging was up to 10% overall and after 50 years, that overall lodging has decreased to 2.5%. There have been substantial improvements over time due to plant breeding, technology, and product development for plant health protection or crop protection. Lodging is very hybrid-specific, so choosing hybrids that are not prone to lodging is necessary to prevent lodging. Hybrid differences are clear every year. Some hybrids have higher numbers, and some hybrids have no issues at all. Using hybrid ratings (if available) can be helpful in the selection process. To use the performance trials for corn hybrid selections, visit: https://ohiocroptest.cfaes.osu.edu/corntrials/
What’s happening in the battle for the belt fields across Ohio?
Both corn and soybean harvest may begin this week at the Western and Wooster location pending the rain in the forecast. The goal is to harvest as each planting date becomes ready for harvest and for the Western location the first three planting dates matured quickly and in a similar time period. March 25th to May 6th soybean planting dates at the Wooster and Western location are ready for harvest. The Northwest location has the first planting date ready (May 16) in both crops. The final planting date in soybeans at all locations is in R6 and is quickly showing the yellowing of leaf drop in parts of plots. Corn development at the Northwest and Wooster locations is slow compared to the soybeans. Corn and soybeans for planting date four and five at these two locations have a long way to go before they are ready to be harvested.
The summary of locations, last week’s weather, planting dates, GDDs and stages is presented in Table 1.