Factors of yield resilience under changing weather evidenced by a 14-year record of corn-hay yield in a 1000-cow dairy farm

Dairy farms can improve their environmental footprint by feeding more homegrown forage. As a consequence, higher yields will reduce feed imports and enhance nutrient use efficiency. To improve forage production, limitations to production need to be identified. In particular, there is a need for long-term yield records, of at least 8 years, to evaluate yield stability and production trends. Such information should allow us to identify the system with the best buffering capacity (resilience) under changing climate. Here, we analyzed 14 years of yield data from a 1000-cow dairy farm. We studied individual field yield and farm-average yields of corn silage and alfalfa and grass hay mixtures. Fields were classified in four quadrants based on yield and yield variability over time. Soil physical and chemical properties were evaluated as potential indicators of biological buffering capacity. Across all fields, corn silage yield increased from 13.3 to 17.8 Mg dry matter (DM) ha−1 between 2000 and 2013 whereas hay yield averaged 8.6 Mg DM ha−1 without a trend. Those findings are explained by timing and amount of rainfall, field drainage, soil phosphorus, and organic matter. Fields with the highest biological buffering capacity averaged 18–20 mg Morgan soil test phosphorus kg−1 and 2.9–3.2 % organic matter versus 9 mg phosphorus kg−1 and 2.7–2.8 % organic matter for low and variable-yielding fields. We suggest therefore that management practices that increase organic matter, improve drainage, and provide optimal soil fertility will result in higher and more stable yields that are less impacted by weather extremes.