Organic materials applied as seed treatments or foliar sprays fail to increase grain yield of wheat

Abstract

Organic materials derived from fish, seaweed or bacterial cultures, and being sold as 'natural' aids to crop production, were tested for their effects on wheat yield in Western Australia. Six products based on seaweed (Seasol powder and liquid, Kelpak 66), fish (Eco, 10.8.8, Crop Booster) or bacterial culture (Cytozyme Seed Plus), and Complesal, an inorganic nutrient spray, were tested as seed treatments or foliar sprays. Thirty-two replicated field trials (plot size 100 m2) were conducted over 3 years using recommended rates of fertiliser and 'commercial' weed and pest control practices. No statistically significant increases in grain yield were detected from the use of any product in any trial. Average treatment grain yields in 18 trials in 1982 ranged from 99.4 to 10 1.2% of the control and in 12 trials in 1983 from 96.2 to 99.3% of the control. The results give no indication that, at the application rates used, organic materials applied as seed dressings or foliar sprays can increase the grain yield of cereal crops in commercial cultivation.