Test Weight and Harvest Losses 10/01/18 2:49:11 PM|
|What to look for----The current weather pattern is conducive to a number of “Wet Harvest” issues—To minimize the impact on your acres—consider the following/plan accordingly:|
Fusarium. Fusarium is commonly associated with ear damage due to insects. It is worse when hot and humid weather coincides with grain fill and drydown. Affected kernels are typically white and may be scattered over the ear or concentrated near the tip. Infected kernels often exhibit a “starburst” pattern and sometimes are associated with kernel sprouting on the ear. Fusarium produces the mycotoxin fumonisin that is toxic to livestock, especially horses and swine.
- Increased chances for corn stalk lodging—Regardless of the reasons the stalks MAY be weak--Have you tested your stalk strength lately? Wet weather this time of year normally increases the chances of stalk lodging--Use the pinch/push test to test for durability. Remember this is all about harvest scheduling at this point IF you have a crushable stalk at or close to the soil line—those fields would be candidates for earlier harvesting regardless of grain moisture… We can discuss the possibilities of why the stalks lost strength at a later date.
- I have noticed 2 Corn Ear Rots-- Corn is susceptible to several ear- and kernel-rotting fungi that reduce the yield potential, quality, and feed value of grain. Greatest losses occur when rainfall is above average from silking to harvest (we had that) or when insects or birds damage developing ears (we had that also—remember Japanese beetles??). Fusarium and Diplodia are the most common ear rots in these parts and this year is no different.
Diplodia. ear rot occurs most frequently in reduced tillage fields and continuous corn. It is recognized by a white to gray mold that usually begins at the base of the ear and develops toward the tip, growing between kernels. That differs from Fusarium which only grows in or on the kernel. With severe infection, the entire Diplodia-infected ear turns gray-brown and completely rots, a symptom known as mummification). Diplodia is favored by wet weather within the first 21 days after silking. Hybrids vary in the level of susceptibility to Diplodia ear rot, but because of the erratic nature of the disease most hybrids are not well characterized, and any hybrid can be infected given the right conditions.
Both of these Ear Fungi are hard to control and/or predict. I have yet to see either one of them affect an entire field. You will normally see this along the edges of the fields where some form of insects have physically injured the developing ear.
- Shattering. Once the soybeans dry out, there can be an increased chance of shattering of the pods. Your earlier maturing varieties are normally more prone for this to occur—schedule harvest accordingly.
- Sprouting/rotting in the pod. Beans that have dried to less than 50% moisture and then take in water again to rise back above 50% moisture can/will germinate. This normally occurs when mature soybeans stand in water for an extended period of time.
- Lodging: This has been a developing issue for the past couple of months—Many of the lodged soybeans have not stood back up much since they lodged due to plant height and storm impact a number of weeks ago. We would hope that harvesting at slower ground speeds will enable the majority of the soybeans to be cut/harvested. This is all dependent on the moisture content or the stems/pods as it may take a bit longer than normal to dry out to enable efficient harvesting.
Is your Test Weight Low? Consider this:
High Grain Moisture--Test weight increases by 1 pound per bushel for every 4 points of moisture drydown. For example, corn harvested at 23.5% moisture with 54 pound test weight is likely to have 56 pound test weight when dried to 15.5%. However, if corn was not able to supply kernels with enough energy to fill, test weight may not increase as corn dries.
Inability to Supply Kernels with Sufficient Energy--Conditions from R2 through black layer (R6) can greatly impact test weight. Once corn is past R2, kernel abortion is un-likely and the number of kernels is fairly set. After black layer, the movement of moisture, nutrients, and energy between kernels and the plant is minimal. If yield potential is higher than what the environment or plant can support from R2 through R6, something has to give. This can result in lower test weights because the corn plant cannot supply kernels with enough energy to fill due to lack of production, damage to plumbing, or premature death.
Corn Plant Cannot Produce Enough Energy. Plants produce energy through photosynthesis (Ps). Drought, leaf diseases, or cloudy or rainy weather can reduce Ps, thereby reducing energy production. Drought stress limits water uptake as well the ability to photosynthesize efficiently. Leaf diseases destroy leaf tissue needed for Ps. Cloudy or rainy weather limits sunshine, thereby reducing Ps.
Damage to Plumbing. The term “plumbing” refers to the xylem and phloem in the plant. The plumbing is needed to move moisture, nutrients, and energy, to sustain the plant and grain. If the plumbing is damaged due to insect injury, stalk rots, stalk lodging or root lodging, it can hinder the ability of the plant to produce and/or send enough energy to developing kernels, resulting in low test weight.
Premature Plant Death. Frost or severe stalk rot infection are common causes of premature plant death (prior to black layer). Often premature death results in the corn cob being mushy and bending easily with your hands. Premature death causes slow drydown. Even when grain from plants that have died prematurely is dried, the water can be removed, but the starch within each kernel does not shrink as it normally would. That results in larger, softer, less dense kernels, and low test weights.
Harvest Losses--Corn and soybeans left behind when the field is combined represent a loss of profits. Harvest losses cannot be completely eliminated, but can be reduced to 1 to 2 bushels per acre by checking the performance of your combine throughout the harvest season
CORN: How to Measure Harvest Loss. Determine total ear loss by counting the number of full-size ears, or the equivalent, in a 1/100 acre area.—17.5 linear feet in 30” row spacings. .Each full-size ear represents about1 bushel/acre loss. To measure kernel loss, count the loose kernels on the ground and those still attached to threshed cobs in a 10 square foot area for each row behind the combine. The area should have width equal to the planted row width. Two kernels per square foot equals a 1 bushel/acre loss.
SOYBEANS: How to measure harvest loss. Losses are determined by counting the number of beans on the ground in a 10 square foot area. By counting the beans in this area and dividing by ten, you can determine the number of beans lost per square foot. Four beans per square foot equals 1 bushel/acre loss. Therefore, dividing the number of beans per square foot by four will provide you with the loss in bushels per acre.
Make loss determinations at several locations and calculate an average.
Because the majority of harvesting losses occur at the gathering unit of the combine, reel and cutterbar, shucking roller and gathering chain adjustments are important to help keep losses at an acceptable level.
John W. McNamara
Wiles Bros. Inc.
606 Wiles Road
Plattsmouth NE. 68048