Methods
Experimental Design
The experiment compares the impact of 3 fertilizer sources on Barley, Wheat, and Canola crop yields on Dryland and Irrigated Sites. Data was collected in 2008 at the research site in Lethbridge, Alberta (Figure 1) which is located in the dark brown soil zone. Urea (46-0-0), Environmentally Smart Nitrogen (ESN; a polymer coated Urea fertilizer), and Blend (25% Urea, 75% ESN) fertilizer sources were applied at rates of 30, 60, 90, and 120 kg Nitrogen/ha. Urea and Environmentally Smart Nitrogen fertilizer sources were fall banded, spring banded, or spring seed placed, and the Blend fertilizer source was spring seed placed only.
Figure 1. Aerial view of the study site.
Treatments were arranged in a 3 way factorial for fertilizer source, fertilizer timing/placement, and fertilizer rate, with 4 replicates for each treatment in a randomized complete block design (Figure 2). In addition, each block had 2 check treatments where no fertilizer was applied (Figure 2). For each experimental treatment an area of 11.34 m2 was harvested and grain yield was determined.
Figure 2. An example of a randomized complete block design for the research experiment.
Statistical Analyses
A series of one way and two-way ANOVAs were completed in R (v4.0.3) to determine the statistical significance of treatment effects on crop yields. Pairwise comparisons using the Tukey method were used to determine statistical significance of means within treatments, and effect size statistics were used to determine yield gains between treatments.
Disclaimer: This website is a project for REN R 690 at the University of Alberta, and was developed solely to fulfill the requirements for the course.