Clean soybean fields look great from the road. But a field with beans planted into sometimes-scrubby looking residue in a no-till system will likely dress up the bottom line.
Ernie Flint, regional agronomist with the Mississippi State University Extension Service in central Mississippi, says conservation tillage, and especially no-till, offer farmers the best chance of saving precious soil that often runs off during heavy rains that are typical across the Mid-South and other areas.
“It may be the best method of farming much of the state’s land and other areas of the South, especially in areas with sloping topography,” says Flint, who works out of Kosciusko, Miss. “However, fighting age-old traditions prevents many growers from adopting the practice.
“We’ve seen a fair amount of acceptance of pure no-till in recent years. But most people in the Mid-South are still not really comfortable with it. I think we’re going in that direction, but it is slow.”
No-till often involves planting soybeans or other row crops directly into stubble or stalk residue from a previous crop. The residue helps retain moisture and crop nutrients and prevents soil erosion, especially in sloping terrain. Earthworms and other soil organisms aerate the soil while preserving its structure.
Slows velocity of water
“Water has to move off a slope, but with no-till, instead of going 40 mph, it goes 2 mph,” he says. “It doesn’t carry much soil at that velocity.”
Flint has worked with numerous growers to successfully use no-till and other conservation tillage methods. In one situation, he worked with a grower who planted soybeans into a 350-acre former cattle ranch.
“Soybeans were drilled directly into existing sod from where hay had been harvested prior to planting,” he says. “The grower applied poultry litter, sprayed the sod with glyphosate and planted with no-till drills.
“I worked with him through our SMART (Soybean Management by Application of Research and Technology) program to select varieties, set the drills and control pests, diseases and weeds. The beans yielded around 60 bushels per acre, without irrigation, on land that no one else wanted to farm until he came along.”
Higher than average yield
MSU Extension says yield is about 20 bushels higher than the average Mississippi soybean yield. The Mississippi Soybean Promotion Board (MSPB) also views no-till and other conservation tillage as ways to prevent soil loss, often caused by heavy rains and excessive runoff.
An MSPB white paper says conservation tillage is recognized as one of the most important developments that have positively impacted crop production agriculture.
“Erosion can be reduced by as much as 50 percent if 30 percent of the soil surface is covered with residue, when compared to bare soil,” MSPB says. “Fuel consumption and cost are minimal.”
In citing a Mississippi soil erosion test, MSPB points out the extensive difference in soil loss between conventional tillage and no-till. In a field with a 5-percent slope on brown loam soil, these numbers are reported:
- Following soybeans, about 21.1 tons of soil per acre was lost in conventional tillage, compared to 1.2 tons in a no-till system.
- Following corn silage, about 11.2 tons of soil was lost in conventional tillage, compared to 0.3 of a ton in no-till.
- Following corn for grain, 7.2 tons of soil was lost in conventional tillage, compared to 0.4 of a ton in a no-till system.
- Following cotton, about 31.2 tons of soil was lost in conventional tillage, compared to 5.4 tons in a no-till system.
- For sorghum, about 4.2 tons of soil was lost in conventional tillage, compared to 0.6 of a ton in a no-till system.
The Soybean Promotion Board notes that residue levels following soybean harvest may be sufficient to meet requirements to reduce erosion for highly erodible land. However, winter decomposition and any fall or spring tillage destroys a significant portion.
Weed resistance considerations
The increasing occurrence of weed resistance to herbicides used in a no-till system or heavy plant residue from a previous crop may require some preplant tillage to effectively manage these conditions in some years.
Flint says a herbicide program that includes multiple modes of action will help farmers maintain a good weed control program in no-till or other conservation tillage systems.
“Some growers are developing a hybrid no-till system,” he says. “It includes a lot less tillage than before. Very little tillage is done in the spring. Some growers alternate tillage from one year to the next. They may till following corn to prepare for beans or cotton the next year.”
Some younger farmers want to incorporate more no-till into a crop rotation they run with their fathers or other older producers, he says. But there is often pressure against them.
“Although the acceptance of no-till has improved in recent years, there is still prejudice against those who ‘farm ugly,’” Flint says. “This should be a no-brainer — but often it’s not.”