Effect of Tillage on Nitrogen Availability to Sugar Beets Years 1 & 2

1. Effect of Tillage on Nitrogen Availability to Sugar BeetsYears 1 & 2 Amber Moore and David Tarkalson University of Idaho – Twin Falls USDA ARS - Kimberly

2. Introduction • Introduction of Round-up Ready sugar beets • Weeds no longer controlled by cultivation • Opportunities for conservation tillage methods, such as strip-till • No-till meets moldboard plow • Only disturbs portion of the soil that contains the seed. • Estimated 1800 acres of strip-till sugarbeets in Idaho in 2008

4. Introduction • Advantages of strip till over moldboard plow • Reducing number of passes • Controls soil erosion • Water retention • Apply chemicals and fertilizers during tillage

5. Introduction • Chisel plowing • Loosens the soil without inverting it • Residues are partially incorporated into the soil • Breaks into plow pan

6. http://www.maes.msu.edu/ressta/saginawvalley/Pic_Tour/14C23chisel_plow.jpghttp://www.maes.msu.edu/ressta/saginawvalley/Pic_Tour/14C23chisel_plow.jpg

7. Introduction • Concerns with strip till and chisel plowing • Organic matter lying on surface, no longer fully incorporated into the soil • Sugar beets highly sensitive to N release rates and release timing • Will reduction of carbon and aeration/mixing slow biological processes such as N mineralization? • Will reduction of carbon lower C:N ratios, thus speeding up N mineralization and slowing down immobilization? • Release of residue N

8. Introduction • Tillage timing • Fall tillage • Allows incorporated residues time to decompose • Potentially less tie-up of N • Spring tillage • Can apply fertilizers and pesticides while tilling (for strip till) • Prevents soil erosion over winter (chisel plow and moldboard plow)

9. Effect of Tillage on Nitrogen Availability to Sugar Beets • Project goal - To determine the effect of tillage method and tillage timing on nitrogen available to sugar beets following a cereal crop

10. Experimental design • Tillage study at USDA-ARS Kimberly • David Tarkalson and Dave Bjorneberg • Three tillage methods • Strip till (ST) • Chisel plow (CP) • Moldboard plow (MP) • Two tillage times • Fall and spring • Five fertilizer N rates, including a control

11. Moldboard Plow

12. Chisel Plow

13. Strip Till

19. Figure 3. Effect of tillage treatment and timing for soil carbon content at a one-foot depth for a Portneuf silt loam at planting, averaged over 2008 and 2009 and over nitrogen rates. CP = Chisel plow, ST = Strip-till, MB = Moldboard plow.

20. Conclusion • It seems that tillage method and timing are more likely to impact nitrogen mineralization in growth limiting environments (lower N, higher C, etc.). • Spring plowed and chisel-plowed soils show the greatest increase in carbon compared to fall plowed and moldboard or strip-tilled soils

21. Thank you!