Effect of conservation tillage on crop yields, soil erosion, and soil properties under furrow irrigation in western Colorado

Conservation tillage (CS) is used widely in rainfed and sprinkler-irrigated production systems but adoption of CS on furrow-irrigated cropland has been limited. Some crops and crop rotations are more conducive to conservation tillage under furrow irrigation than others. The objective of this research was to evaluate CS in a furrow-irrigated crop rotation of corn, soybean, winter barley, and dry bean at Fruita, Colorado in 1991 and 1992. Infiltration rates were 24 and 50% higher and advance times were 37 and 25% longer in the CS treatment during 1991 and 1992, respectively, compared with conventional tillage (CV). Furrows in the CV treatment were 8 and 25% wider than those in the CS treatment after the first and sixth irrigations, respectively. This indicates more soil movement with CV than with CS. In 1992, soil water content in the CS treatment was 17, 17, and 27% higher than with CV throughout the growing season for corn, soybean, and dry bean, respectively. Grain yields of winter barley, soybean, dry bean, and corn were not affected significantly by tillage treatment. Profitability of CS and CV was quite similar when all four crops in the rotation were considered together. This research was conducted under conditions expected to be similar to those that could be used by growers and indicates that corn, soybean, winter barley, and dry bean can be grown successfully in rotation using conservation tillage under furrow-irrigated conditions. Successful adoption of conservation tillage under furrow irrigation will require growers to adopt encompassing new production management practices and possibly purchase new equipment such as planters and cultivators that will operate in high residue conditions, and growers must overcome any psychological barriers they may have to maintaining high amounts of surface crop residue when furrow irrigating.