Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/30/2016
Publication Date: 7/31/2016
Citation: Yost, M.A., Kitchen, N.R., Sudduth, K.A., Drummond, S.T., Sadler, E.J. 2016. A decade of precision agriculture impacts on grain yield and yield variation. In: 13th International Conference on Precision Agriculture Proceedings, July 31-August 3, 2016, St. Louis, Missouri. Available: https://ispag.org/proceedings/?action=abstract&id=2109&search=types.
Interpretive Summary: The ability of precision agriculture to maintain or increase grain yield has not been evaluated at a field scale over long periods of time. Starting in 1993, grain yield and other spatial data were measured across a 88-ha field with claypan soils near Centralia, Missouri. For the first 11 years (1993-2003), the field was managed conventionally with annual rotations of corn and soybean, annual tillage, and uniform chemical inputs. For the next 11 years (2004-2014), the field was managed as a precision agriculture/conservation system with cover crops, no-tillage, crop rotation changes, and variable-rate chemical inputs. As one of the few fields in the United States with over two decades of spatial yield data, this information offers a valuable look at the capabilities of precision agriculture. Results showed that a decade of a precision agriculture system maintained, but did not increase, corn or soybean grain yield. However, the precision agriculture system did cause less variation in grain yields from year to year in many areas of the field, despite more extreme weather conditions than during the conventional management. These results indicate that yield may be more stable from year to year with precision agriculture and conservation. This information will aid in the further acceptance and use of conservation practices by farmers and farm advisors on claypan landscapes. Increased use of conservation practices should maintain farmer’s long-term crop yields, reduce variability in their crop yield, and increase the stability of their yields across a range of growing conditions.
Technical Abstract: Targeting management practices and inputs with precision agriculture has high potential to meet some of the grand challenges of sustainability in the coming century, including simultaneously improving crop yields and reducing environmental impacts. Although the potential is high, few studies have documented long-term effects of precision agriculture on crop production and environmental quality. More specifically, long-term impacts of precision conservation practices such as cover crops, no-tillage, diversified crop rotations, and precision nutrient management on field-scale crop production across landscapes are not well understood. To better understand these impacts, a 36-ha field in central Missouri was monitored for over a decade as both a conventional (1991-2003) and a precision agriculture system (PAS) (2004-2014). Conventional management was annual mulch-tillage in a 2 yr corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation. Key aspects of the PAS were the addition of no-tillage, cover crops, winter wheat (Triticum aestivum L.) instead of corn on areas with shallow topsoil and low corn profitability, and variable-rate nutrient (N, P, K, and lime) applications. The objective of this research was to evaluate how a decade of PAS influenced temporal and spatial dynamics of grain yield. In the northern half of the field, wheat in PAS had higher relative grain yield and reduced temporal yield variation on shallow topsoil, but reduced relative grain yield on deep soil in the drainage channel compared to pre-PAS corn. In the southern half of the field where corn remained in production, PAS did not increase yield, but did reduce temporal yield variability. Across the whole field, soybean yield and temporal yield variation were only marginally influenced by PAS. Spatial yield variation of any crop was not altered by PAS. Therefore, the greatest production advantage of a decade of precision agriculture was reduced temporal yield variation, which leads to greater yield stability and resilience to changing climate.