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The author of the reading believes that three proposed solutions would be effective in controlling the invasion of the cheatgrass plants. The speaker in the listening, however, casts doubt on this claim by saying that the methods would not work very well to achieve the purpose.
First of all, the author points out that releasing grazers such as cattle and other livestock in the field would result in the reduction of cheatgrass. This point is challenged by the speaker. He explains that cheatgrass is not the grazers’ preferred option for food. Specifically, he argues that when grazers are in a field with cheatgrass and other kinds of plants, they would choose to eat the latter first. Although they might eat some of the cheatgrass, this would only happen after their consumption of other native grasses and plants. Thus, encouraging grazers to feed on cheatgrass would probably cause the unwanted opposite effect with fewer native grasses and plenty of cheatgrass.
The author goes on to contend that using controlled fires to burn the cheatgrass off the fields would be a viable solution. The lecturer rebuts this argument. He suggests that the effect of the burning-it- off plan would fail to be profound and lasting. He elaborates on this by mentioning that cheatgrass produces a myriad of seeds, which can germinate even a few years after falling to the ground. Many of them get pushed down into the soil, making it impossible for the fire to harm them. Therefore, after the fire has burned away cheatgrass plants and seeds on the surface of a field, those that are buried in the soil will sprout and give rise to new plants. The result is that the field will soon be filled with cheatgrass again.
Finally, the author states that the introduction of a fungal parasite that specifically attacks cheatgrass would do. The lecturer, on the other hand, argues that this approach can hardly be the case. He puts forth the fact that cheatgrass and the fungal parasite have been co-existed in their native habitats for thousands of years. This relationship allows cheatgrass plants to have been able to develop some resistance against the fungus. Although the fungus has the ability to harm those weak or sickly cheatgrass plants, the healthy and strong ones can usually resist the fungal infection. Consequently, introducing the fungal parasite will probably not be efficient.