Predicting the mass emergence of Vulpia bromoides

摘要

Vulpia bromoides (L.) Gray (hair grass) is a serious grass weed of New Zealand cereal crops, contaminating seed and reducing yield. Optimal management of this weed may be achieved when the environmental factors that affect its emergence are well understood. Emergence may then be predicted and manipulated through land management techniques, e.g. through the promotion of germination (irrigation) or the prevention of it (soil inversion), thus enabling optimisation of weed control. The hydrothermal timefor germination of V. bromoides was determined in order to better understand when germination and emergence occurs and how environmental conditions including soil temperature (T) and water potential (*T) may influence this. The germination profile of V.bromoides was determined on a thermogradient table. Seeds were also incubated under constant factorial combinations of temperature and water potential in order to better understand the water potential required for the germination of this species. The rate of germination of V. bromoides was slowest from 5 to 7°C and most rapid from 13 to 32°C. At temperatures of 5 to 15°C V. bromoides experienced reduced germination rates at water potentials between -0.75 to -1.00 MPa. At temperatures of 20 and 25°CV. bromoides germinated rapidly across all of the water potentials assessed. These results will inform the development of optimised weed management on farm.