Direct drilling experiments with wheat

Abstract

Results are presented from three experiments, on land being cropped for the third time after a ley period, in which the growth and nitrogen nutrition of direct drilled and conventionally cultivated and sown wheat was investigated. In 1968 and 1969 wheat growth from emergence to heading was superior on the cultivated plots but grain yields did not differ. In 1970 direct drilling increased wheat grain yield by 0.97 tonne ha-1. Nitrogen fertilizer application at seeding increased herbage dry matter and nitrogen content, fertile tiller production and grain yields on both direct-drilled and cultivated treatments. Soil mineral nitrogen levels at seeding were lower on cultivated plots than on direct-drilled plots, but incubation nitrogen was not different in any year. Direct drilling did not adversely affect mineralization of soil nitrogen, but it retarded early wheat growth.