|Jabro, Jalal "jay"|
|Iversen, William - Bill|
|Stevens, William - Bart|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2015
Publication Date: 5/22/2015
Publication URL: http://handle.nal.usda.gov/10113/61038
Citation: Jabro, J.D., Iversen, W.M., Stevens, W.B., Evans, R.G., Mikha, M.M., Allen, B.L. 2015. Effect of three tillage depths on sugarbeet response and soil penetrability resistance. Agronomy Journal. 107(4):1481-1488. DOI: 10.2134/agronj14.0561.
Interpretive Summary: Soil tillage is an important agronomic practice that requires considerable expense and high-energy inputs, is carried out to create favorable soil conditions for plant growth and development. A 4-yr study was conducted on a Lihen sandy loam soil to evaluate the effect of tillage depth on sugarbeet (Beta vulgaris L.) root yield, root quality, and soil penetration resistance (PR). Tillage treatments consisted of no-tillage (NT), shallow tillage (ST), and deep tillage (DT). Results from this 4-yr tillage depth study conducted in a sandy loam soil lead to several conclusions. No statistically significant differences attributable to tillage method were found for root yield or sucrose yield except in 2010. Root nitrate was not affected by tillage treatment in any if the 4 yrs. This showed the viability of NT and reduced tillage systems in sugarbeet production and practical faming in general. Deep tillage often provides healthier soil physical conditions that promote a more favorable soil environment for plant growth compared to both ST and NT systems. Soil PR was significantly influenced by the depth of tillage for all 4 yrs. Averaged across 0-to 40 cm depth, mean profile PR values were significantly lower in DT than in NT and ST. The lower PR values under DT were likely associated with greater soil loosening and overturn induced by deep tillage, thereby forming more soil macropores for DT as compared with those under ST and NT practices. Despite the healthy soil ecosystem caused by the DT operations, our results showed that neither sugarbeet yield nor root quality was significantly impacted by the DT relative to both NT and ST practices except in 2010. We hope that findings from this 4-yr study will motivate sugarbeet producers in the region and elsewhere in the world to consider a shift to no tillage and reduced tillage systems rather than using costly and time consuming conventional tillage practices. Using no tillage or reduced tillage practices will save producers money due to reduction in input costs while still maintaining crop profitability and quality compared to conventional tillage practices. While NT is considered a promising practice as compared to conventional tillage, further research is still needed to validate our results on different soil types and conditions prior to making any recommendation for adapting NT practices for sugerbeet production in this region.
Technical Abstract: Tillage can alter soil properties and affect crop yield and quality. A 4-yr study was conducted on a Lihen sandy loam soil to evaluate the effect of tillage depth on sugarbeet (Beta vulgaris L.) root yield, root quality, and soil penetration resistance (PR). Tillage treatments consisted of no-tillage (NT), shallow tillage (ST), and deep tillage (DT). Soil PR was measured with a penetrometer in 2.5-cm increments to a 40-cm depth at three locations within each plot. Roots were hand harvested from each plot and each sample consisted of roots of two adjacent rows. Sugarbeet root yield and adjusted sucrose yield were not significantly affected by the depth of tillage in 2008, 2009, and 2011. In 2010, root yield was significantly greater (16.5%) in DT than in NT. The average sugarbeet yields across 4 yrs were 58.77, 60.30, and 63.03 Mg ha-1 for NT, ST, and DT, respectively. Root yield was lower in 2011 than other three years due to cold and wet weather conditions in the spring. Soil PR values were significantly lower in DT than in ST and NT from 5- to 30 cm depth. However, significant differences were found between ST and NT at the 5- to 7.5 cm depth. Overall, DT enhanced soil physical environment but on average across 4 yrs had no statistically significant effect on sugarbeet root yield and quality compared to both ST and NT practices, though a trend was noted that as tillage depth increased root yield increased.