Texas A&M University Specialists and County Agents from surrounding counties put on a Field Crops Tour June 16 at the Farm Services research fields in the Brazos River bottom in cooperation with the Tri-County Crops Committee, the Brazos Valley Water District and Robertson County Farm Bureau.
Dr. Clark Neely and Dr. Ronnie Schnell started the day speaking about soybean and corn cropping rotations. They are three years into a six-year trial being conducted in conjunction with Mississippi State. The trial is being funded by the U.S. and Mid-South Soybean Boards.
Several different crop rotations are being studied under dryland and irrigated conditions, as well as testing the effectiveness of removing crop residue through burning.
“Right now we are getting mixed results with the burning, but the yields are really pretty close,” Neely said. “We have not yet seen a consistent difference either way.
Neely also pointed out that the extremely wet spring in 2015 hurt yields and temporarily skewed results. Corn and soybean yields were basically cut in half, while grain sorghum yields were down only about 14%. Double-cropped soybeans behind wheat also performed very poorly due to the very dry conditions during the summer.
“Based on the data right now, continuous corn production looks the best, but we are only three years in,” said Schnell. “Additional years of data may tell a different story in the end.”
Weed Science Program Specialist Matt Matocha discussed the weed management trials he is currently conducting in cotton, soybean, sorghum and corn. The untreated rows were easy to spot as they were well covered with grass and pigweeds. Matocha explained which herbicide program had been used on the other rows, commenting on the efficacy of each type of treatment.
“It is best to spray weeds that are 4” or less in height,” Matocha stressed to the gathered producers. “Timeliness is most critical to application, especially when you are trying to control herbicide resistant weeds. If you spray weeds such as Palmer pigweed and waterhemp beyond 4”, you decrease you chances of controlling them completely.”
At the cotton fields, Dr. Gaylon Morgan told the gathered producers that some of the Texas Department of Agriculture (TDA) regulations have changed regarding hormone-type herbicides. The modifications to the TDA rules will allow farmers to utilize the new Enlist and XtendFlex technology, one labeled, the new herbicides will have very strict application requirements stated on the labeled.
“Where they used to have application recommendations there will now be very specific application requirements,” Morgan stressed. “Tank-mixtures, tip size, tip type, wind speed, boom height, and other requirements will all be very explicitly specified. Updates on label requirements will be put on the companies’ (Dow AgroSciences and Monsanto) websites, and it will be the applicators responsibility to stay current on the application requirements.”
Ronnie Schnell is conducting two separate fertility trials in his sorghum fields. The fertilization rate trial is intended to determine the application rate that produced the best yields, as well as the rate at which the greatest financial return per acre is realized.
“We determine the economically optimum application rate of the fertilizer by comparing yield per acre and cost per acre,” Schnell explained.
The second trial compares the timing of fertilizer applications to determine the optimum application window and the potential to extend that window with starter fertilizer.
Schnell also discussed the current sugar cane aphid problems being seen by producers. Some aphids were found in the test plots, but not yet enough to require intervention.
“We want to see fewer than 50 to 100 aphids per leaf” Schnell explained. “We are not at those numbers yet, but will monitor them very closely.”
In addition to insects and fertility issues, water issues can cause problems in irrigated crops, according to Forage and Water Extension Program Specialist Matt Brown. While the surface waters in Texas have a range of problems, from bacterial impairment to nitrate impairment, dissolved solids (primarily salts) can have the most serious impact.
“Dissolved solids are caused by runoff, underground formations and by evaporation and they cause two problems for crops,” Brown told the gathered producers. “Salt buildup can bind the water in the soil, making less available to the plants and the sodium damages the structure of medium to fine soils causing crusting and a loss of soil density.”
According to Brown forages are usually the most tolerant to high salt levels, followed by the field crops. Fruits are the least tolerant.
Brown suggested management practices to battle salt and sodium build-up include modified seed placement, using crop residue to reduce evaporation, increased or modified irrigation methods and chemical amendments to the soil.
“There is no cookie cutter answer for salinity management. There are too many variables,” said Brown. “Management depends on the soil and water samples and the irrigation method used on a field. It must all be done on an individual basis.”
As with many management decisions, Brown suggested it is best to consult with a specialist before initiating a remedy. He explained that AgriLife has a variety of publications, including one which addresses the critical salt levels for a variety of field crops.