Submitted to: WSU Dryland Field Day Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2014
Publication Date: 6/20/2014
Citation: Paulitz, T.C., Jacobsen, J., Schofstoll, S. 2014. Management of Fresh Wheat Residue for Irrigated Winter Canola Production. WSU Dryland Field Day Abstracts. 14-1. Pg. 54. Interpretive Summary:
Technical Abstract: Winter canola is popular with many irrigated growers as it provides excellent disease control benefits for potatoes grown in rotation. There is a belief among irrigated canola growers that fresh wheat residue must be burned and the soil then heavily tilled before winter canola is planted. These growers are convinced that fresh (i.e., newly harvested) wheat straw is toxic to winter canola. We are conducting a three-year field experiment in a Mr. Schibel’s field near Odessa, WA, as well as greenhouse and laboratory tests to: (i) determine how five different winter wheat residue management practices affect the plant health and seed yield of winter canola; (ii) find the cause(s) for any decline in winter canola vigor and seed yield as affected by management of fresh winter wheat residue, and (iii) test methods to retain winter wheat residue without adversely affecting winter canola health and seed yield. Our hypothesis is that fresh wheat stubble is not phytotoxic to canola and that winter canola can be successfully produced in a direct-seed system after wheat harvest as a viable alternative to field burning plus heavy tillage. Five winter wheat stubble management treatments are established in late August – early September, just prior to planting winter canola. These treatments are: (i) Stubble burned + disked; (ii) stubble chopped + moldboard plowed; (iii) stubble burned, then direct seeded; (iv) direct seeding into standing and undisturbed stubble (Fig. 1 & 2); and (v) winter canola broadcast into the standing (i.e., not yet harvested) wheat crop. Application of irrigation water, which totals 15 inches for the crop year, is managed by Mr. Schibel as part of his normal irrigation schedule for winter canola. No root or foliar diseases were detected in any of the treatments in 2013. Winter canola seed yields in 2013 ranged from 3014 to 3276 lbs/acre with no statistical differences (P=0.40) among treatments.