THE IMPACT OF TRASH AND TILLAGE MANAGEMENT OPTIONS AND NEMATICIDE APPLICATION ON CROP PERFORMANCE AND PLANT-PARASITIC NEMATODE POPULATIONS IN A SUGARCANE/PEANUT FARMING SYSTEM

PLANT-PARASITIC NEMATODES (PPN) are a significant productivity constraint in the sugarcane farming systems of the Bundaberg/Childers region. This experiment was established to examine the impact of strategies like trash retention and reduced tillage on nematode populations and crop performance. A sugarcane field that was due for plough-out had two trash managements, green cane trash blanket (GCTB) retained or residues removed by burning (Burnt), split for two tillage treatments, conventional tillage (Conv.) and direct drill (DD). The site was sown to peanuts in August 2010. Following the peanut crop, the tillage treatments were re-instituted and sown to sugarcane (KQ228) in September 2011 using a double-disc opener planter. When the established cane crop was at the four leaf stage all plots were split for +/– nematicide. Nematicide was applied to see if this option would retard the reinfestation of PPN during the plant cane phase. Treatments were split again for +/– nematicide in the ratoon phase. Trash management had no impact on peanut productivity whereas tillage did. The Conv. treatment produced 39% greater peanut yield than the DD treatment. Early plant cane development was retarded in the DD plots, a trend that continued through to the harvest of the plant cane crop where the Conv. treatment improved productivity by 36% compared to DD plots. However, there was no tillage effect on cane productivity in the R1 crop. While nematicide application in the plant cane crop significantly reduced total PPN numbers, there was no impact on yield. Application of nematicide to the ratoon crop significantly reduced sugar yield. This study confirmed other work demonstrating implementation of strategies like reduced tillage reduced populations of total plant-parasitic nematodes (TPPN) in the ratoon phase; suggesting that the soil was more suppressive to PPN in those treatments. Further work is required to over-come the lack of crop performance when the DD treatment is implemented for the peanut break crop and in the plant cane phase.