Impacts of Agronomic Practices on High-Yielding Wheat Fields in Kansas.

Wheat (Triticum aestivum L.) grain yields are stagnant in several water-limited growing environments across the globe. Improved management will be crucial to increase food production and help meet future food demand while minimizing environmental impacts. We used a unique management-by-yield database comprised of 91 intensively-managed fields entered in the wheat yield contest during the 2010-2016 harvest seasons to identify opportunities to increase wheat yields and decrease the footprint of agriculture in Kansas. Descriptive statistics were used to describe management practices adopted in these fields, and management-yield relationships were explored using Pearson’s correlation coefficient; linear, multiple, and quantile regression analyses; and t-tests between high- and low-yielding fields determined as terciles in the dataset. Wheat grain yield averaged 5.4 Mg ha^-1 and 50% of the fields yielded between 4.6 and 6.1 Mg ha^-1. Wheat yields were correlated to but significantly greater than the official state averages during the study period. Agronomic practices positively associated with grain yields across all statistical approaches were no-till, late-season foliar fungicide, in-furrow phosphorus (P) fertilizer, and variety maturity. Varieties with greater susceptibility to fungal diseases significantly responded to foliar fungicide while resistant varieties did not. Maximum yield (quantile: 0.99) was 7.3 Mg ha^-1 and was decreased in 1.9 Mg ha^-1 for every one million seeds ha^-1 increase in seeding rates above 2.8 million seeds ha^-1. Wheat grain yield did not respond to fertilizer rate, which highlights an opportunity to decrease environmental impacts by using soil tests to determine fertilizers requirements and avoid over-fertilization. Early-season fungicide application showed no yield benefit within our dataset. Our research explored a unique dataset of intensively managed wheat fields grown in a water-limited environment to develop improved agronomic recommendations, ultimately aiming to increase food production while decreasing the environmental footprint of agriculture.