Fall tillage; is it IN or is it OUT?

Fall Tillage Is It IN Or Is It OUT?

ASK MOST product managers how much soil should be fall-tilled and with what implements and the answer is a quick "none.' But, Larry Van Etten, DMI marketing director, says, "We make tools for fall tillage, so we encourage their use.'

Van Etten says that although tillage of some soils should wait until spring, most soils can be fall-tilled and that loosening soil permits more water to soak in. Tilled surfaces usually dry faster in spring, too. He adds that on sloping land, exposed residue and the loose, roughened surface left by fall tillage can slow runoff and helps store more water for next year's crop.

Dealers have a unique opportunity and responsibility to encourage responsible tillage of erodible soils, say several company product managers. Dealers using conservation tillage or no-till equipment on farms they own and operate seem to sell more soil-saving equipment to customers than do dealers who don't have farms of their own, says Glenn Olson, Deere tillage product and market planning manager.

Lew Swoverland, Deutz-Allis tillage product manager, says the company's no-till pioneering, company/dealer-sponsored field days and winter customer meetings, plus involvement in Soil Conservation Service and similar programs all help dealers sell soil-saving tillage equipment.

But Olson points out that soil and water conservation are mostly a welcome fringe benefit of farmers' efforts to save money by reducing tillage operations.

Van Etten adds that many of the "You can't do . . .' rules of reduced tillage and no-till heard in the past are no longer true. No-till can now be successful on many flat, black soils, and changes in planters and cultivators make it easy to operate in surface residue without reducing yields.

Yields with conservation tillage and no-till are often higher than with conventional tillage, and Van Etten adds, "The main difference is that we've all learned how to manage these practices and the new machines that have developed with them.'

Olson adds that some flat, dark, poorly-drained soils without serious water erosion problems become very cloddy if primary tillage waits till spring, and they may respond best to fall moldboard plowing. However, a few farmers are successfully using ridge-till on some of those same problem soils.

Fall-till soybean stubble?

Never fall-till soybean stubble, say many agronomists and equipment experts. But Olson notes that some ridge farmers fear ridging soybeans may rob them of a few lower pods and thus cut yields, so they don't rebuild ridges for corn until after harvest. He adds that fall ridging may cover most of the residue and thus lead to increased wind and water erosion, even if ridges are contoured.

Van Etten suggests that farmers review this year's conditions before ruling out fall tillage of bean ground. For example, was spring tillage and planting completed when the soil was dry, or was it wet and compactable? Were there many heavy, three- to five-inch summer rains? These can increase compaction, too. Was soil wet during harvest and heavily compacted by combines, tractors, wagons and trucks?? If it was at one or more of these stages in the season, says Van Etten, fall tillage may be worthwhile if most residue is left on the surface.

Implement of choice

Dick-chisel and coulter-chisel combinations are most frequently recommended by product managers for fall tillage. The amount of residue left exposed by these units depends on the disk setting and points used on the chisel section. Olson says twisted shovels leave 40-60 percent of residue exposed and deep furrows which may increase erosion if the machine is operated uphill and downhill.

But he adds that in Deere tests, wide sweeps running six to eight inches deep left 70 percent of the residue exposed, without increasing draft. Sweeps also eliminate furrows left by narrow chisel points or twisted shovels. Sixteen-inch sweeps were used on chisel plows and disk-chisels with 12- and 15-inch shank spacings respectively. Disk- and coulter-chisel combinations have been most widely accepted in the Corn Belt, with scattered use in other parts of the country.

On the other hand, surface residue interferes with furrow irrigation, and most cotton growers, worried about insect survival in residue, also prefer clean tillage to mulch farming. Northern farmers, especially those with flat, poorly drained soils, face the dilemma of winter wind erosion from clean tilled fields or slower soil warmup in spring caused by erosion-controlling surface residue.

Tillage vs. fertilizer placement

Some farmers and a few plant and soil scientists say soil must be moldboard-plowed at least every few years to mix fertilizer into the root zone. But John Fox, Case IH tillage specialist, says need for deep fertilizing depends on soil condition, basic fertility level and available soil moisture.

When rainfall is adequate, he says, plant roots proliferate near the surface and obtain enough nutrients from the major supply concentrated within the upper 2-3 inches of soil. He adds that in dry years, more tillage and deeper fertilizer mixing may be needed for optimum crop growth. Van Etten and some product managers agree, but Swoverland says deep placement is unnecessary in most areas and that starter fertilizer costs less than broadcast applications anyway.

Most agree with Swoverland that revival of starter fertilizer application with planters and drills, possibly with more added during cultivation, reduces the need for deep tillage to mix fertilizer into the soil. Knifing-in anhydrous ammonia is generally one of the lowest-cost means of applying nitrogen, says Olson, and it places N where it will do the most good for plants. But occasional deep banding or mixing of P and K may still be needed on some soils.

Rotate tillage and crops

Swoverland and Olson agree that no-till and no-plow reduced tillage usually causes changes in dominant weed species. Because roots aren't severed annually, deep-rooted perennials may cause more trouble, but regular shallow tillage may encourage germination and depletion of the supply of annual weed seeds near the surface and eventually, fewer weed problems. It's widely agreed that weed control chemicals and equipment must be changed and adapted, sometimes annually, during the first few years after switching from conventional tillage.

Olson adds that monoculture crop or tillage equipment systems usually lead to weed, insect, fertility and/or compaction problems. Thus, some farmers now keep a broader line of equipment than they had in the past. They may disk, moldboard plow, chisel plow or no-till certain fields or for certain crops. However, some who kept moldboard plows for occasional use after switching to no-till or conservation tillage say they haven't plowed as often as expected, if at all.

Ridge-till may lead to monoculture problems, says Olson, and it generally requires better management and more timely operations than conventional tillage operations. Row crops must be cultivated on time--usually twice--or not at all. But yields from well-managed ridging operations are usually as good as or better than yields from the same fields with conventional tillage.

Power down

Most specialists agree that maximum tractor size required for conservation tillage is no more, and usually less than for conventional tillage of an equal acreage. Where no-till is most widely used, dealers sell fewer large tractors than in the past, and total implement sales are down because fewer implements are needed to raise a crop, says Swoverland.