June is a great month in the cropping year. We entered this month in 2009 with cooler weather and a bit on the dry side. This dry weather allowed farmers to get the first crop of alfalfa up with little or no rain for the first time in years. Since the first week of June we have received a lot of rain and the corn and soybeans have really taken off. I heard an anecdotal report of an area farmer who placed a yardstick in his cornfield and reported that the corn had grown 6 inches in a 24 hour period. That is truly remarkable and is indicative of corn's ability to grow rapidly when conditions are right.
Crop producers are optimistic by nature. Each spring when planting their crops the general attitude is that this year's crop will be great and that there will not be any problems. Yet, as we know, problems always seem to sneak in and we need to take the time to scout our fields and see what is out there.
There are weed, fertility, insect, and disease situations that could show up at any time. Often, poor or stunted growth can be a consequence of one or more of these factors. With the use of genetically engineered hybrids and varieties, poor growth caused by one or more of these factors just mentioned can be controlled or eliminated from consideration.
A good practice when diagnosing crop problems in the field is to gather some soil and/or plant samples. That's the best place to start. This collection cannot be a random process. A systematic approach is likely to produce information that is useful. When considering a problem that might be related to soil fertility and fertilizer use, three plant and corresponding soil samples are important. One set of samples should be collected from the area where the stunting or damage is most severe. This area is usually quite obvious to anyone who has experience with crop production. A second set of plant/soil samples should be collected from an area in the field where crop growth appears to be normal without stunting and discoloration. A comparison of the results of the analysis of these plant and soils samples can yield some useful data. Let's look at some ideas to diagnose problems in the field.
CORN: Early in the season, now would be a good time, scout your fields and look for some problem areas. When you see an area of the field with problems, collect several whole plants and cut them off at the soil surface. If the plant is between waist high and silking, collect the leaf at the top of the canopy. Very useful information can be obtained by having an analysis done by a laboratory to determine if the plants are experiencing a nutritional deficiency or a disease problem.
Soybeans: Throughout the season, if problems are observed, collect the most recently emerged leaflet. A sample of 50 leaflets is usually satisfactory for lab analysis.
Small Grains: Early in the growing season, collect whole plants. After flag leaf emergence, collect the flag leaf. This leaf is the one that emerges just before the head. This sample should consist of 25 to 30 plants.
Alfalfa: Collect the top 6 inches of the alfalfa plants. Again, 25 to 30 plants should be sufficient.
You can do two things at this point. You can spend the money and have a lab analysis done. Or you can take the time to look the plants over yourself or have your agronomist take a look at them the get their input. The important point here is to take the time to walk your fields and see if you have any problem areas that you cannot get a good view of from the road. A little time spent now can head off major problems down the road.