Crop responses to deep incorporation of soil amendments in contrasting soils and climates

High rates of composted chicken manure led to increased grain yields only in high rainfall environments. In low rainfall environments, early to mid season biomass was increased but there was no yield benefit. Deep incorporation of amendments resulted in inconsistent results. Deep placement of sulphur, acid sand and gypsum increased yields at the Nangeenan site in 2015 but not in 2016. Deep incorporation of gypsum and manures resulted in yield increases at Ongerup in 2016 but not in 2015. No benefit from deep incorporation of manure or lime was found at Esperance. Surface straw mulching at Nangeenan resulted in higher biomass but did not affect grain yield.