Project Update: Year Three
Building on the information gathered from phytotoxicity and field efficacy trials in the first two years of the project, research in the third year has focused on ways to manage the most troublesome species in mown vegetation in eastern Australia – Bahia grass (Paspalum notatum). This grass readily invades mown vegetation in sub-tropical and tropical regions, replacing more desirable turf grasses and often becoming totally dominant. During the growing season (i.e. from spring to autumn) it rapidly produces tall seed-heads after being mown, thereby triggering more frequent mowing activities than would otherwise be necessary.
Field efficacy trials have been conducted at two sites during the 2009/2010 growing season, one located on the Gold Coast and the other in Brisbane. Two separate trials have been run at both of these locations, one with the goal of suppressing the seed-head production of Bahia grass, and the other with the goal of transitioning Bahia grass out of the turf and allowing more desirable lower growing species (i.e. couch grasses) to take over the area. The integrated strategies being trialled involve the strategic use of selected plant growth regulators and/or herbicides in combination with much-reduced mowing regimes.
Results from the suppression experiment indicate that a single application of the right products, at the right rates, at the right time, can totally suppress the seed-head production of Bahia grass for up to 12 weeks during the peak of the growing season. Meanwhile, results from the transition experiment have shown that two or three strategic selective herbicide applications throughout the growing season are all that is required to transition a Bahia grass dominated site into one that is dominated by desirable couch grasses.
The most promising chemical products in these trials have the added benefit of controlling a broad spectrum of broadleaf weeds without having any significant phytotoxic effects on desirable grass species, thereby increasing the quality of the mown vegetation. They also have low toxicities, are relatively environmentally friendly, and require low levels of active ingredients to be applied.
The integrated strategies employed in these experiments have demonstrated the ability to significantly reduce the number of mowing cycles required in a growing season. Hence, their correct application in the right situations has the potential to provide a more economical and sustainable model for the management of mown vegetation.
Field efficacy trials have been conducted at two sites during the 2009/2010 growing season, one located on the Gold Coast and the other in Brisbane. Two separate trials have been run at both of these locations, one with the goal of suppressing the seed-head production of Bahia grass, and the other with the goal of transitioning Bahia grass out of the turf and allowing more desirable lower growing species (i.e. couch grasses) to take over the area. The integrated strategies being trialled involve the strategic use of selected plant growth regulators and/or herbicides in combination with much-reduced mowing regimes.
Results from the suppression experiment indicate that a single application of the right products, at the right rates, at the right time, can totally suppress the seed-head production of Bahia grass for up to 12 weeks during the peak of the growing season. Meanwhile, results from the transition experiment have shown that two or three strategic selective herbicide applications throughout the growing season are all that is required to transition a Bahia grass dominated site into one that is dominated by desirable couch grasses.
The most promising chemical products in these trials have the added benefit of controlling a broad spectrum of broadleaf weeds without having any significant phytotoxic effects on desirable grass species, thereby increasing the quality of the mown vegetation. They also have low toxicities, are relatively environmentally friendly, and require low levels of active ingredients to be applied.
The integrated strategies employed in these experiments have demonstrated the ability to significantly reduce the number of mowing cycles required in a growing season. Hence, their correct application in the right situations has the potential to provide a more economical and sustainable model for the management of mown vegetation.
posted by Steve Hampton at
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