EFFECTS OF DIFFERENT WATER AND NITROGEN REGIMENS ON YIELD OF WINTER WHEAT PRODUCED IN NEBRASKA

Authors

Joseph Emory DavisFollow

First Advisor

Dipak Santra

Date of this Version

12-2019

Document Type

Thesis

Citation

Davis, Joseph E. 2019, Effects of Different Water and Nitrogen Regimens on Yield of Winter Wheat Produced in Nebraska

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agronomy, Under the Supervision of Dipak Santra.Lincoln, Nebraska: December 2019.

Copyright (c) 2019 Joseph Emory Davis

Abstract

Wheat is the 3rd most prominent crop in the USA and approximately 50% is exported annually. Nebraska wheat production is 11^th in the country, and it plays a major role in the state's agricultural economy, especially in western NE. Generally, wheat is grown under dryland conditions and the region grows much more wheat on unirrigated land than it does on irrigated. However, deficit irrigation has shown great value in producing high yielding wheat with much less water than needed for other crops. Finding new ways to leverage irrigation in wheat production may help address the need to produce food with fewer inputs. The objective of this project was to evaluate the effect of nitrogen, irrigation, and cultivar on grain yield and quality. A randomized complete block with split-split plots was used as the design for this experiment. Six cultivars were (Anton, Armour, Overland, Settler-CL, Snowmass, Wesley), five nitrogen treatments (0, 30, 60, 90, 120 lbs of N per acre) and three irrigation treatments (0, 6, 12 inches) were used. Plots were harvested when mature using small plot combines equipped with onboard weighing systems. Differences between years had a dramatic effect on yield across all treatments and all locations. However, when correcting for rainfall, location didn't have a substantial impact on yield. Irrigation events only occurred at the Scottsbluff location. Irrigation had a significant effect when compared to dryland production, but the effect of 6 and 12-inch irrigation treatments was subtler and at times not significant. Nitrogen had little effect on yield or predicted grain protein. Variety had a significant effect on both yield and predicted grain protein, and this trend was consistent across years and locations. Test weight (TWT) was not responsive to nitrogen or irrigation, but varietal differences were significant and some trends remained constant from year to year. However, TWT trends did not align between locations in either year. Gluten response was very similar to protein, but the response was much less dramatic.

Advisor: Dipak Santra