News Release
October 9, 2003
By Dave Pfarr Regional Extension Educator
Agricultural Production Systems –
Crops
Preparing the fields for 2004
Harvest is a time to reflect on the management practices of the past year and effects they have had on the yields of the current crop. In general the soybean yields have been less than average and the corn yields may come in at average or above average. In most years soybean and corn yields track each other fairly consistently. A good growing environment for one crop will usually benefit the other. This year will be different due to the late season drought which accentuated the differences between the critical development stages of the corn and soybean crops. Field corn benefits most from ideal growing conditions with adequate precipitation in May, June, July. This year the field corn experienced excellent early season growth and excellent pollination conditions in mid July. After the critical pollination period is satisfied for corn and the kernels are set there is very little uncooperative weather can do to significantly reduce the yield of the crop short of an extreme hail event. Soybean yield responds to a different set of environmental pressures. While the soybeans enjoyed the same early growth as the corn, the August weather during the critical soybean reproductive period of pod and seed development came up short. 2003 will not be remembered fondly by many farmers but it was a great laboratory for learning and observing how crops respond differently to the timing of weather extremes.
The 2003 growing season will not change management practices significantly for field corn but it may serve as a reminder of why timeliness of field operations are so important to attain high yields. Fall soil sampling for organic matter, pH, phosphorus and potassium will help determine appropriate fertilization and liming rates. Fall soil sampling is also one more piece of information if the previous crop was variable in performance across the field. Most fields have enough variability to warrant grid sampling to truly understand where limiting yield factors may be present. Grid sampling is not necessary each year but should be considered on a 4 to 5 year cycle. Sampling fields every 4th or 5th year on a rotation will also ease the expense of grid sampling on the farming operation.
Fall nitrogen application with anhydrous ammonia for corn production is allowed in South-Central Minnesota after the soils attain and remain at 50 degrees farhenhiet or less in the application zone. This usually occurs after Oct. 25th. The corn crop did not experience nitrogen deficiency in 2003 but fall applied NH3 in some years will denitrify and move to surface water before crop utilization. This can lead to measurable yield losses in some years. Many soils have properties which will benefit from the addition of a nitrogen stabilizer applied with fall applied anhydrous ammonia.