It won't be long until it's time to begin the task of filling planter hoppers, officially beginning the soybean growing season. And, if you haven't yet booked your seed for 2003, you may find little more than an empty warehouse when you visit your seed dealer.
“Soybean seed is going to be tight this year, and the best varieties are probably gone at this point. If you haven't made your varietal decisions, you need to do that as soon as possible,” advises Alan Blaine, Extension soybean specialist at Mississippi State University in Starkville, Miss.
Blaine, who spoke to growers at a recent rice and soybean production meeting in Marks, Miss., says there are more than 200 commercial soybean varieties available today, making variety selection an “overwhelming task.”
In an effort to highlight top-performers, Blaine has devised a short list of consistently high-yielding soybean varieties. Inclusion on his list, he said, was based entirely on a variety's yield and ability to perform consistently over several different environments. Variety selections were based on 2002 performance, long-term yield averages, and field operations. Purposely avoided were brand new varieties, or varieties with a limited history.
“The best variety trial ever is the one conducted on your farm. Do not hesitate to plant several varieties, but plant new varieties in limited quantities to evaluate them under your management and environment,” Blaine says. “Although yield is a major criteria in variety selection, be mindful of things like stem canker and nematodes. If specific problems exist, choose from the list accordingly.”
Conventional varieties on Blaine's “short list” include Group IV varieties: Delta Pine 4748S, Hornbeck 4891, and Progeny 4910. Conventional Group V varieties recommended are: Delta Pine 5110S, Progeny 5600, Hutcheson Public, Unisouth Genetics 5601T, Delsoy 5500 Public, Progeny 5120N, Armor 52-C2, Delta King 5995, Hornbeck 5991, and Pioneer 9594.
Roundup Ready varieties that made Blaine's list of top performers, in order of maturity, include: Asgrow 4403, Asgrow 4702, Croplan Genetics 4444, UAP DG 3443NRR, Asgrow 4902, Delta Grow 4950, Delta King 4868RR, Delta Pine SG 498RR, Hartz 4994RR, Hornbeck R4820, Hornbeck R4920, Cache River Morsoy RT 4809, Pioneer 9492, Pioneer 94B73, Asgrow 5701, Delta King 5366RR, Hornbeck R5620, Asgrow 5501, Delta Grow 5630RR, UAP DG 3535 NRR, Delta King 5661RR, Southern States RT 557 N, Terral Seed 56R11, Delta Pine 5915, and Pioneer 95B96.
While Blaine is of the opinion that Group III soybeans offer possibilities, he says the varieties currently available are not yet ideally suited for Mid-South soybean production. With that in mind, however, his “short list” of top performers does include Delta King 3964 and Asgrow 3702, both Group III Roundup Ready varieties.
For those growers considering planting early-maturity varieties in an early-planted production system, Blaine stresses the need for harvest efficiency. “If you are not willing to get in the field and harvest early-planted soybeans when they are ready, don't plant them. Timely harvest is critical,” he says.
Choosing the ideal planting date for your area and field conditions can also greatly affect yield potential. In Mississippi research tests, a planting date 10 days later than the recommended ideal date decreased yield by 50 percent. “That's especially true in dryland fields, because you can make up some lost time with irrigation. Even with irrigation, though, you will never hit the higher yield levels with a May 15 or later planting date,” Blaine says.
To avoid a replant situation, he suggests planting early-maturity soybeans into a well-drained field, just below the soil surface where the ground is warmer. In addition, Blaine recommends applying a seed treatment that protects from pythium, and using an inoculant treatment for soybeans planted following a cotton rotation.
When it comes to seeding rates, Blaine says, “You would be shocked at how low you can go on seeding rates. We've got a lot of room to fudge, with high-yield potential possible even with seeding rates of 28 to 32 pounds of seed per acre. The important thing is seed placement.”
Before putting your soybean seed in the ground, maintenance applications of phosphorus and potash may be required to reap the highest possible yields.
According to Blaine, more than 50 percent of soybean growers in the Mississippi SMART program found they needed a maintenance fertilizer application in 2002. A simple mathematical equation can help estimate the amount of phosphorus and potash your field needs.
Using your 2002 average per acre yield for that field, multiply the number of bushels harvested by 0.8 to calculate the amount of phosphorus needed. To determine how much maintenance potash is needed, multiply the number of harvested bushels per acre by 1.4.
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