Two things, first let's start with the commercial and industrial land. The US policymakers on both sides of the aisle have deindustrialized us and have tried to make us a service-based economy. So heaven forbid a foreign company comes in and actually engages in some productive activity here. If the Chinese are really doing this at level that is cause for concern, then you need to be questioning WTF do the Chinese see here that domestic producers do not see and utilize?
With regards to farmland, what is the major concern here? Now I agree that the situation in Arizona and alfalfa farming and the depletion of the aquifers is an issue. But outside of a situation like that, what harm is it really in them having the farm land? Is it your desire to see this farm land be used by Americans? If so, will it be just a hand over from the Chinese to a multination company based here? What kind of GMO/frankenfood/glyphosate crops are they going to be growing? And the assumption is that they are growing for domestic consumption or will they be still using the farm land to serve the needs of China?