Strip tillage and high-efficiency irrigation applied to a sugarbeet- barley rotation

Authors: Stevens, William - Bart; Evans, Robert; Iversen, William - Bill; Jabro, Jalal - Jay; Sainju, Upendra; Allen, Brett

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2015
Publication Date: 4/15/2015
Publication URL: http://handle.nal.usda.gov/10113/60754
Citation: Stevens, W.B., Evans, R.G., Iversen, W.M., Jabro, J.D., Sainju, U.M., Allen, B.L. 2015. Strip tillage and high-efficiency irrigation applied to a sugarbeet-barley rotation. Agronomy Journal. 107(4):1250-1258. DOI: 10.2134/agronj14.0525.

Interpretive Summary: Energy and water are limited resources throughout the world and both must be used efficiently to ensure a secure and abundant food supply. Strip tillage and high-efficiency irrigation methods reduce fuel and water inputs compared to conventional practices, but have not been extensively evaluated in sugarbeet (Beta vulgaris L.)-malting barley (Hordeum vulgare L.) cropping systems. Strip tillage is a one-pass tillage system that results in the tillage of a narrow strip of soil where seed is to be planted while stubble between seed rows remains undisturbed. Fertilizer is applied in simultaneously during the tillage operation. This tillage practice reduces energy input costs and protects seedlings from wind-blown soil. Low-energy precision application (LEPA) irrigation applies water using low-pressure streams of water via specially-designed nozzles attached to automated sprinkler irrigation systems. The efficiency of LEPA nozzles (estimated to be greater than 95%) is higher than most alternative nozzle designs because nozzles are close to the ground (about 15 cm) and produce virtually no small water droplets. A four-year field study was conducted to compare (1) conventional and strip tillage practices, and (2) conventional mid-elevation spray application (MESA) and low-energy precision application (LEPA) irrigation methods for their effects on yield and quality of sugarbeet and malting barley. Results of this study show that fall strip tillage is a viable alternative to conventional practices for sugarbeet producers. Sugarbeet yield with strip tillage equaled that with conventional tillage. Observations over the four-year study period suggest that spring soil moisture at the seeding depth is greater with strip tillage than with conventional practices when offseason precipitation occurs; however, in-season soil moisture readings for the total profile did not differ for the two tillage systems. Malt barley yielded 8% less when strip tillage rather than conventional tillage was used for the previous sugarbeet crop. There was between 9 and 14% more soil profile moisture during the barley growing season following conventional tillage-sugarbeet than when following strip tillage-sugarbeet. Sugarbeet yield was similar for the two irrigation methods suggesting that both LEPA and MESA provided sufficient soil moisture levels to optimize yield; however, soil profile moisture was greater with LEPA during the late growing season, probably reflecting the greater application efficiency of this method. Lower levels of impurities in the root suggest that extraction efficiency is greater when sugarbeet is grown with MESA than with LEPA, particularly under strip tillage. Barley yield and quality were largely unaffected by irrigation method and soil profile moisture was similar under both MESA and LEPA methods. Based on these results, LEPA is an effective irrigation method for malt barley and sugarbeet production under environmental and management conditions similar to those described for the study site. An economic cost comparison suggests that adopting strip tillage for sugarbeet production may reduce tillage and fertilizer application costs by 54% for the sugarbeet phase of a sugarbeet-malt barley rotation; 38% for the whole rotation. Further savings may be realized by adopting a LEPA irrigation method which has been estimated to reduce energy costs by 20 to 40% compared to higher pressure systems.

Technical Abstract: Strip tillage (ST) and high-efficiency overhead irrigation methods reduce fuel and water inputs compared to conventional practices, but have not been extensively evaluated in sugarbeet (Beta vulgaris L.)-malting barley (Hordeum vulgare L.) cropping systems. A field study comparing conventional tillage (CT) and ST systems and two sprinkler irrigation methods (mid-elevation spray application, MESA; low-energy precision application, LEPA) was conducted near Sidney, MT from 2005 to 2008. ST was performed (for sugarbeet only) using a single operation that left alternating 30-cm wide strips of tilled and untilled soil. Fertilizer was banded 10 cm deep during the tillage operation. CT for sugarbeet consisted of six separate field operations using different tillage implements, all performed following a broadcast application of fertilizer. Tillage preceding malt barley consisted of one pass each with a disk and a field cultivator following a broadcast application of fertilizer. Sugarbeet grown with ST yielded as well as when grown with CT. Irrigation method did not affect sugarbeet yield. Malt barley yield was not affected by irrigation method but in three of five years was 8% lower following ST sugarbeet than when following CT sugarbeet. Tillage and fertilizer application costs for the sugarbeet phase of the two-year rotation were estimated to be approximately $115 ha-1 less with ST than with CT representing cost reductions of 54% for the sugarbeet phase alone and 38% for the two-year cropping system. It was concluded that both ST and LEPA are potentially beneficial practices in irrigated sugarbeet-malt barley cropping systems.