Nitrogen, phosphorus, and potassium fertility requirements for optimizing protein levels in malting barley
For optimum economic returns, fertilizer applications should be managed to apply sufficient N to attain the highest possible yield, without increasing protein content beyond the acceptable levels. For optimum profitability, a fertilizer management system must consider the balance among the major nutrients rather than simply N and moisture in isolation.
IPNI-1990-CAN-MB4
24 May 2001
Methodology
- Plots were established in the spring of 1990 on two sites, a Souris fine sandy loam on the Brandon Research Station and a Newdale Clay Loam, near Clanwilliam. Under normal conditions, the sandy soil is prone to drought and the clay loam soil is relatively moist. Sol samples were taken in the fall of 1989 and analyzed for N, P, K, S, pH and conductance. Moisture content to 120 cm was measured in the spring, prior to seeding.
An overall application of 50 kg S ha-1 as elemental sulfur was applied to the sandy loam soil on April 23 and the clay loam soil on May 22, 1990. Roundup was sprayed on the clay loam site on May 22. Treflan and Avadex (0.61 and 1.42 1/acre, respectively) were applied as a tank mix on the sandy loam soil on May 4 and the clay loam soil on May 28. Seeding was conducted on the sandy loam soil on May 10 to 11 and on the clay loam soil on May 28. Ellice, a two-row and Argle, a six-row cultivar were sown on each site. Fertilizer was side-banded through the drill at time of seeding 2.5 cm below and to the side of the seed-row. Fertilizer was supplied in a full factorial with N as ammonium nitrate at 6 levels from 0 to 150 kg N ha-1, K as potassium chloride at 0 and 100 kg K ha-1, and P as monoammonium phosphate at 0 and 40 kg P2O5 ha-1. A Banvel-MCPA tank mix (95 ml and 350 ml/acre, respectively) was sprayed on the clay loam soil on June 14, and Estaprop (0.71 1/acre) was sprayed on the clay loam soil on June 26.
Common root rot severity was measured at early tillering (June 15) on the phosphate treated 0, 30 and 150 kg N ha-1 treatments, with and without KCl. Root rot was rated on a scale of 1 to 4 on 5 plants per plot. Biomasss yield and nutrient content were measured at early heading (July 9 on the sandy loam and July 20 on the clay loam) on two 1 meter lengths of row. Nutrient analysis at heading is not completed and so cannot be presented. Grain yield, protein content and malting quality were determined at maturity (14% moisture). Final yield was taken on August 13 on the sandy loam and September 12 on the clay loam soil.