Development of Strip Tillage on Sprinkler Irrigated Sugarbeet

Authors: Evans, Robert; Stevens, William - Bart; Iversen, William - Bill

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2009
Publication Date: 9/30/2009
Citation: Evans, R.G., Stevens, W.B., Iversen, W.M. 2010. Development of Strip Tillage on Sprinkler Irrigated Sugarbeet. Applied Engineering in Agriculture. 26(1): 59-69.

Interpretive Summary: A project to evaluate new technologies for strip tillage of small seeded crops was initiated in fall 2003 near Sidney, Montana for sprinkler irrigated sugarbeet (Beta vulgaris L.) to be grown in 2004. Strip till treatments were compared to conventional grower tillage practices in fifty-six 15 m by 25 m (48 ft by 80 ft) side-by-side plots. Both treatments were flat planted with no ridges or beds. All tillage and fertilization was done in the fall after removal of a malt barley crop. Thirty centimeter (12 inch) wide strips were tilled directly into the straw residues about 20 cm (8 inches) deep using straight and paired fluted coulters and a modified parabolic ripping shank followed by a crows-foot packer wheel. Toothed-wheel row cleaners were installed in front of the straight coulter to move loose residue to the side to avoid plugging. At the same time, dry fertilizer was shanked (banded) about 8 to 13 cm (3 to 5 in.) below the anticipated seed placement location. Sugarbeet were planted about 2.5 cm (1 in.) deep with 60 cm (24 in.) spacing between rows in the spring. Five years of results have shown that strip tillage will produce yields comparable to conventionally tilled sugarbeet in the Lower Yellowstone River Valley. These experiments have shown that strip till yields were at least equal to conventionally tilled beets, but with many fewer passes of equipment and considerable savings in fuel and time. In addition, the presence of standing small grain residue before each sugarbeet crop potentially makes strip tillage a viable way to reduce the risk of crop damage due to soil erosion by wind in the spring. One of the central tenets of this research is that strip tillage is not just a minimum tillage technique. Strip tillage necessitates new considerations for tractor, planting, cultivation and harvesting equipment. It must be an integral part of an entire cultural system that minimizes equipment passes through the field. The straw and chaff must be evenly distributed. Fertilization rates, timing and placement may have to be altered. Use of strip tillers in sugarbeet rotations after small grains will require some changes to planting and cultivation equipment and practices to handle high residue levels. Herbicide and other pest control programs may also have to be modified to be effective in high residue conditions. Beet harvesters may require some adjustments in very heavy soils if residue and mud build up on cleaning rolls. It should be noted that the strip tillage treatment did not require any more tillage than the conventionally tilled treatment following sugarbeet harvest before the succeeding barley crop. High level guidance of the strip tiller, planting, cultivations and any other subsequent machine operations is especially critical. Mechanical or hydraulically assisted RTK-GPS guidance is highly recommended for both the tiller and the planter to ensure accurate placement of both fertilizer and seed within the strip. However, if strip till, fertilizing and planting are being done in one operation in the spring, the high level guidance systems are probably not necessary. Fertilizer use patterns appear to be somewhat different under strip till than under conventional tillage due to a combination of the effects of nitrogen placement (i.e., banding vs. broadcast) and mineralization of crop residues and soil organic nitrogen, which tends to be more rapid with full-width tillage than with reduced tillage. Further work is needed to determine if banding nitrogen fertilizer under the strip tillage system affects the optimum fertilizer application rate as compared to conventional practices, but this research suggests that current fertilizer recommendations are adequate for strip till systems.

Technical Abstract: A project to evaluate new technologies for strip tillage of small seeded crops was initiated in fall 2003 near Sidney, Montana for sprinkler irrigated sugarbeet (Beta vulgaris L.) to be grown in 2004. Strip till treatments were compared to conventional grower tillage practices in fifty-six 15 m by 25 m (48 ft by 80 ft) side-by-side plots. Both treatments were flat planted with no ridges or beds. All tillage and fertilization was done in the fall after removal of a malt barley crop. Thirty centimeter (12 inch) wide strips were tilled directly into the straw residues about 20 cm (8 inches) deep using straight and paired fluted coulters and a modified parabolic ripping shank followed by a crows-foot packer wheel. Toothed-wheel row cleaners were installed in front of the straight coulter to move loose residue to the side to avoid plugging. At the same time, dry fertilizer was shanked (banded) about 8 to 13 cm (3 to 5 in.) below the anticipated seed placement location. Sugarbeet were planted about 2.5 cm (1 in.) deep with 60 cm (24 in.) spacing between rows in the spring. Toothed-wheel row cleaners were also placed in front of each row on the planter to move any residue displaced by winter storms. Operation of the strip tiller required about 25 tractor horsepower per row, but substantial fuel savings were realized with this system by reducing the number of tractor equipment field passes by up to 75%. In 2004, 2006, 2007 and 2008 there were no significant differences in yields or sugar production between the two tillage treatments; however, in 2005 the strip tilled plots produced about 17% greater yields (tonnage and gross sugar). This benefit in 2005 was primarily due to the standing straw stubble in the strip tilled plots that protected sugarbeet seedlings from blowing soil during a spring wind storm that severely damaged seedlings in the conventionally tilled plots where there was no surface crop residue. It was concluded that strip tillage must be considered as part of a larger cropping system that affects timing and equipment choices for planting, cultivation, spraying, and harvesting as well as tillage and other cultural practices. Based on these results, it is generally recommended that strip tillage should be performed in the fall on clay soils in eastern Montana where it has been shown to result in better seedbed conditions than spring strip tillage. Whereas lighter, sandy soils would probably produce equally well when strip tilled in the spring, which could then be combined with planting into a single pass tillage, fertilizing and planting operation. Banding fertilizer is highly recommended under strip till to increase fertilizer use efficiencies and reduce input costs. RTK-GPS guided steering in combination with some type of mechanical steering assistance on the implements are also recommended for both strip tilling, planting and cultivation (if needed).