Home » Grow Crops » Grow Corn » Corn Crop Science » Measuring Corn Quality

Measuring Corn Quality

By Dr. Harold Willis

Are high quality crops important to you? Is it really worth all the trouble it takes to grow better crops?

If you are feeding your crops to your animals, then you probably can see the value of feeding more nutritious feed and getting higher-producing and healthier animals. Even here, some of the “experts” tell us that it doesn’t pay economically. That it is easier and cheaper to just give the animals vitamin and mineral supplements to make up for what should be in the crops — but isn’t. But is it really better that way?

Often the synthetic vitamins that are used in most supplements aren’t able to be effectively utilized by your animals. Animals (and people) do better when they eat a well-balanced diet containing vitamins, minerals, enzymes, amino acids, proteins, etc., in natural forms.

Even though the nutritionists and biochemists insist it makes no difference, a man-made feed mix or supplement can never have all of the literally hundreds of organic substances contained in the cells of healthy plants — not only vitamins, amino acids, and proteins, but also nucleic acids, nucleotides, peptides, amines, purines, phospholipids, enzymes, coenzymes, flavins, flavenoids, carotenoids, cytochromes, alkaloids, organic acids, polyphenols, and many others you have never heard of.

Even minerals such as calcium must be changed into organic forms by being complexed by a living plant or the microorganisms in an animal’s digestive tract in order for best usage by the animal. So in spite of what the experts say, animals are living organisms and function best when fed high quality, natural food.

OK, you say — so high quality is important when you feed your crops, but I grow corn to sell, and the market only pays for bushels; why should I worry about quality? First of all, you aren’t really paid by volume — bushels — but by weight — a 56 lb. bushel as a standard. The heavier your corn, the more profit you make.

Test weight can be easily measured: Take 2 quarts (dry measure) of corn and weigh in ounces. Subtract the weight of the container. The weight in ounces equals pounds per bushel. For example, if 2 quarts weigh 54 oz., the test weight is 54 lbs. per bushel.

High quality grain will automatically have a higher test weight, plus will not be docked because of cracked kernels or mold. Partly because of the large amount of horribly poor quality grain now being grown, the market is starting to pay a premium for high quality, especially foreign markets. Also, if you grow high quality grain, you should investigate specialty markets which will always pay a premium, such as poultry feed and bird seed companies, zoos, bakeries, and health food companies.

You can also come out ahead in the long run by striving for high quality crops because of the money you can save in grain drying, preservatives, fuel (good soil is loose, easier to work), and veterinary bills, to name a few.

How to tell corn quality

How can you recognize high quality corn, and how can you test your own corn for quality? We mentioned some of the signs of high quality in previous chapters: a deep, strong root system, vigorous growth, freedom from diseases and pests, early maturity with the plant staying green, well-filled cobs (more than one good cob per plant), high test weight, and kernels that do not mold in storage.

Brix standard test corn

Refractometers for corn quality

Another way of measuring crop quality as well as monitoring the plant’s health while it is growing is to use a refractometer to measure sugar content. A refractometer is a precision optical instrument that allows you to quickly measure the percent sugars in the sap of a plant, which is correlated with the plant’s food-producing efficiency (photosynthesis) as well as with food value — protein and mineral content.

Refractometers are routinely used in the food industry, by canneries, wineries, and breweries for example, to measure the quality of the fruits and vegetables they buy from farmers or of the foods and drinks they manufacture.

Using a refractometer is easy. Simply squeeze a few drops of juice from the stems or leaves of the plant onto the glass prism of the refractometer, close the “lid,” and look through the eyepiece. The sugar content is read on a numbered scale in units called Brix (same as percent).

By comparing with standard levels (see Brix table above) or past readings that you have made, you can see how your crops measure up that day. You should realize, however, that the sugar content will vary — from one plant to another, from one part of the plant to another (higher in leaves and upper stalk), in different weather and times of day (higher on warm sunny days in the afternoon), and for sick and healthy plants (sometimes a sick plant will give a high reading if the sugar isn’t being carried into the cob like it should be). So you should be careful to check the sugar content at the same place in the plant (say 3rd leaf-level of the stalk, or cob level), and at the same time of day on sunny days.

corn quality refractometer

Other tests for corn quality

What about standard lab tests for grain and feed quality? One of the most commonly used tests, crude protein, tells you almost nothing. It doesn’t even measure protein, but only estimates it, by multiplying the nitrogen content by 6.25. If there is a high amount of nitrate or other non-protein nitrogen present, the result is meaningless.

Other tests, such as digestible protein, total digestible nutrients (TDN), crude fiber, and dry matter are also estimates of food value. An amino acid analysis is another, more accurate, but very expensive test.

All in all, the cheapest, quickest, and easiest food value test is the sugar content reading made with a refractometer, since mineral content and truly usable protein content are directly correlated with sugar content (unless the plant has a high sugar reading but is obviously sick).

Ordinary lab tests do not measure how well your animals can utilize protein. A crop with a high protein test from a lab but a low refractometer reading would not be as good for animals as one with a high refractometer reading and a lower protein reading.

And then, the ultimate test of crop quality is how well your animals do on it. They should give good gains and production, be healthy, and reproduce well (if other factors are adequate, such as water quality, ventilation, and environment). You can even use the refractometer to test the animals’ urine and immediately see how they are doing on a certain batch of feed.

Source: How to Grow Top Quality Corn