Impact of conservation tillage and nitrogen on sugarbeet yield and quality

Authors: KESHAVARZ AFSHAR, REZA - Colorad0 State University; CHEN, CHENGCI - Montana State University; NILAHYANE, ABDELAZIZ - Montana State University; HE, HUAGIN - Fujian Agricultural & Forestry University; Stevens, William - Bart; Iversen, William - Bill

Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2019
Publication Date: 4/17/2019
Citation: Keshavarz Afshar, R., Chen, C., Nilahyane, A., He, H., Stevens, W.B., Iversen, W.M. 2019. Impact of conservation tillage and nitrogen on sugarbeet yield and quality. Soil and Tillage Research. 191:216-223. https://doi.org/10.1016/j.still.2019.03.017.
DOI: https://doi.org/10.1016/j.still.2019.03.017

Interpretive Summary: Sugarbeet is an important cash crop grown with irrigation in the Lower Yellowstone River Valley of eastern Montana and western North Dakota. Production of this small-seeded crop has typically involved extensive soil tillage to control weeds, incorporate crop residues and produce a fine seedbed. The sugarbeet crop is grown for its sucrose-rich root and leaves only small amounts of crop residues after harvest. This low residue return to the soil combined with the intensive pre-plant tillage and soil disturbance associated with root harvest leave the soil susceptible to degradation by organic matter decomposition and soil erosion. Decreasing the amount of tillage needed for sugarbeet production may enhance soil quality; however, adoption of conservation tillage practices by sugarbeet growers is still low due to a lack of information about how these practices compare to conventional tillage systems in terms of yield and nitrogen response. ARS scientists in Sidney, MT collaborated with Montana State University scientists to compare conventional tillage with strip-tillage and direct seeding (no-till) practices. They confirmed earlier research that shows yield with strip tillage compares favorably to that with conventional practices. Results from the limited amount of research comparing no-till sugarbeet production with conventional practices are more variable but yield with no-till is often lower. This collaborative research showed that yield with no-till was about the same as that with full tillage and that the amount of nitrogen fertilizer required is the same for all three tillage systems. Eliminating tillage provided growers with a cost savings of $111 per hectare. Much more research is needed but these results suggest that no-till sugarbeet production is a promising alternative to conventional practices.

Technical Abstract: Conventional and intensive tillage (CT) is widely practiced in sugarbeet growing regions (Beta vulgaris L.). Limited information exists showing the performance of this crop in reduced tillage systems compared to conventional systems. A three-year field experiment with a split-plot arrangement based on RCBD with four replicates was conducted to evaluate yield and quality of sugarbeet under no-till (NT), and strip-till (ST) systems compared to CT. The response of sugarbeet to increasing rate of N from 56 to 224 kg ha-1 in each tillage system was also studied. Sugarbeet plant stand, root yield, root impurities (sodium, potassium, and amino-N concentration in the root), sucrose loss to molasses (SLM) and recoverable sucrose yield were measured. Tillage had no significant effect on plant stand, root yield, and recoverable sucrose yield and similar yields were obtained from CT, ST, and NT. The estimated cost of tillage operation showed that growing sugarbeet under NT was US$ ha-1 111 cheaper than that in CT which could be translated into US$ ha-1 111 higher net benefit for growers considering the similar yields in both systems. Sugarbeet root yield linearly increased in response to increasing rate of N, however, sucrose concentration decreased and root impurities increased in this situation. Overall, no changes were observed in recoverable sucrose yield when N rate increased. Response to N rate occurred irrespective to tillage method.