Deep cultivation of a sandy soil, near Esperance, reduced the incidence of Rhizoctonia bare patch and increased grain yield of lupins

Abstract

The incidence of rhizoctonia bare patch in lupins was decreased by increasing the depth of cultivation on a grey sand at Gibson, Western Australia. With a shallow 5 cm cultivation, 18% of the plot area was covered with rhizoctonia patches. Deep ripping with an Agrowplow to 20 cm reduced the area of patch to 7%. Deeper ripping to 30 cm further decreased the area of patch. The area covered by rhizoctonia patches was negatively related with lupin yields and accounted for 65% of the variation of dry matter yields of lupin whole tops and 70% of the variation in grain yields. The increase in lupin grain yield as a result of the cultivation (deep ripping) could possibly be due to the reduction of rhizoctonia patch area and any effects that cultivation alone had on lupin growth. The effects of cultivation (deep ripping) and rhizoctonia bare patch on lupin grain yields cannot be separated in this experiment.