Mississippi soybean harvest has progressed extremely well except during the last several days of August. Yields have varied, but as a whole have far exceeded most expectations. Excellent quality can be attributed to better overall stink bug control and wider use of foliar fungicides.
This year's soybean crop will be the highest-yielding ever in Mississippi.
Several items need addressing in the coming weeks. First, it will be a long time until a killing frost. If you harvested early, weed emergence and growth will be rampant. The best control will be either tillage or a fall burndown program.
Although Valor has gotten a lot of attention as a residual material, I believe it is too early to get the most from it. The best time for Valor in Mississippi would be mid-November to early December or in the spring.
We observed a major difference in rows versus flat plantings this year. If I could choose only one production practice in the early planting system, it be rows. It is not feasible on all acreage, but I predict we will see more emphasis on rows and wide beds, which aid in early-season growth and development. Simply put, they improve drainage. Poor drainage is our number one nemesis of yields.
It was obvious deep tillage played a significant role in yields this season. Effective deep tillage is much easier following early harvest. To be most effective, it must be done in a dry profile.
If you plan to till, consider a tillage rotation that allows you to spread your work load and takes advantage of the residual effects of tillage.
Research has shown that tillage on certain soil types has carryover effects. The effects of tillage are visible on heavy clay soils tilled one year out of three to four. The sandier a soil, the more consistent the response to deep tillage. However, for maximum advantage, tillage must not delay planting. Delays are more of a concern for early planting. To avoid these delays, drainage must be adequate.
Deep tillage is not a substitute for irrigation, but it can help the crop during dry weather. Tillage will be of little or no benefit on furrow-irrigated and flood-irrigated fields, but it can help tremendously on most pivot-irrigated fields. Most of the benefit is due to soil type, but the type of irrigation system is a factor, too.
Tillage is not essential on all acres, but it is an option. If you plan to rework land or bed up a field, consider deep tillage before bedding.
With a month and a half to prepare land, consider these: (1) only till where it will help, (2) do not perform deep tillage if it will adversely impact planting date, and (3) improve drainage before considering the first two options.
Take time to open tail ditches so fields drain faster. A row or bed will help, but only if water can get off the lower end of a field. Larger pipes on field ends may be all that is needed to improve drainage.
We know the importance of drainage, but it is often neglected or the last thing considered. Poor drainage continues to be the number one factor affecting yields. This is obvious this year because yields are off some in many better-irrigated (heavy) fields. Typically, they are the most consistent-yielding fields, but mid-June rains had an impact.
Another area we must not overlook is soil fertility. Put something back to continue good yields. Do not guess at soil fertility; pull soil samples. You have time this fall to take care of any deficiencies.
Fertility on the soils (heavy) where we typically grow soybeans is often okay, but in the last two years in the Delta, half the fields in our SMART program have needed maintenance applications of P and K. Although the heavy clays are often higher in fertility and more uniform, they often would benefit from fertilization.
Beans planted on cotton soils especially need attention. These soils are much more variable, and a year like this one will allow you to map soils.
Deficiencies seen in beans were probably there in the other crops (cotton and corn). In addition to P and K, two micronutrients, boron and sulfur, are getting more attention.
Do not overlook soil pH, especially on fresh-cut ground. Irrigation water will increase pH of the soil, but it will not do it overnight nor in one watering. Some lime may be needed to adjust the pH; after that, the crop can take care of itself. I see this problem quite often, but very few farmers apply lime to cut ground.
You have to give to get. It took a long time for deficiencies to surface in the Delta, but depleted soils must be replenished to maintain production.
A final point to consider is crop rotation. Do not get too far from this option. Prices dictate what we do, but try to not grow beans over two consecutive years if possible. You can go longer, but yields will be more consistent if you rotate crops.
An older gentlemen told me years ago that we can grow only three things without rotating — cotton, pastures, and pine trees. Think about it!
Alan Blaine is the Mississippi Extension soybean specialist. e-mail: firstname.lastname@example.org