Fertility Research on Hard Red Spring Wheat

Chapter 6 – Fertility, No. 10, Winter 1987

Roger Veseth

There is an increasing interest in hard red spring wheat as an alternate crop in the Pacific Northwest, Little is known, however, about the management considerations for dryland growing conditions in this region.

Fertility Research Project

The fertility management aspect of hard red spring wheat production under no-till was the focus of a 1986 STEEP research project by USDA-ARS soil scientist Robert Papendick at Pullman, WA. The research was conducted at the Palouse Conservation Field Station north of Pullman. Wampum hard red spring wheat was seeded on April 11 directly into spring cereal stubble using the USDA III (plot-sized Yielder) drill.

Four nitrogen (N) forms (ammonium nitrate, aqua ammonia, uran and urea) were compared in deep band applications at two different rates, 34 and 58 pounds/acre N. A starter fertilizer combination of 16 pounds/acre N, 33 pounds/acre phosphorus (P₂0₅) and 20 pounds/acre sulfur (S) as 10-34-0 plus Thiosol was applied either in the seed row or in the deep band with the bulk of the N fertilizer. Including the starter nitrogen, total nitrogen applications were 50 or 74 pounds/acre N.

One Year’s Results

The results of the 1986 experiment are summarized in Table 1, The application of 58 pounds/acre N together with starter fertilizer in the deep band significantly increased yields over that of starter fertilizer alone either in the deep band or in the seed row. There were no significant differences between N forms at the 58 pounds/acre rate. Although slight yield increases generally occurred with the 34 pounds/acre N rate, only the uran application was a significant increase, and that yield was not statistically different than the yield with the 58 pounds/acre N rate of the four N forms.

In the two comparative treatments evaluated, placing the starter fertilizer in the seed row gave an apparent decrease in yield of about 2 to 3 bushels/acre compared to placing it in the deep band. However, this yield decline was below the 3.8 bushels/acre difference (LSD) necessary to be statistically significant. Yield was not decreased in the one treatment where no starter fertilizer was applied in the seed row or deep band. This indicates that P and S nutrient levels in the soil were not the most important yield-limiting factors.

Treatment samples are currently being analyzed for protein content since percent protein is an important factor in determining the market price of hard red wheat. The influence of fertilizer form, rate and placement on protein level will also be evaluated in this study.

Table 1. Nitrogen form, rate and starter fertilizer placement effect on yield of no-till Wampum hard red spring wheat, 1986, Pullman, WA (Papendick, USDA-ARS).