Long-Term Impact of Precision Agriculture on a Farmer's Field.

Targeting management practices and inputs with precision agriculture has high potential to meet some of the grand challenges of sustainability in the coming century. Although 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 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 (CONV) (1991-2003) and a precision agriculture (PA) system (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 PA system were the addition of no-till, cover crops, winter wheat (Triticum aestivum L.) instead of corn on 21 ha, and variable-rate nutrient (N, P, K, and lime) applications. The objective of this research was to evaluate how over a decade of PA influenced grain yield and yield variation. In the northern half of the field, wheat in PA 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 CONV corn. In the southern half of the field where corn remained in production, PA 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 PA. Spatial yield variation of any crop was not altered by PA. Therefore, the greatest production advantage of a decade of PA was reduced temporal yield variation, which leads to greater yield stability and resilience to changing climate.