The cultivation of food and materials, specifically from or derived from plants and animals using traditional or modern industrial practices.
That strongly implies, at least to me, that all of agriculture is on topic at this site. Given that, the basis for closing the recent spate of agriculture questions is (at least to me) dubious. This is not like the recent "let's stop identifying rocks" debate. Those rock questions were of very limited applicability. Questions about agriculture can have a much wider applicability than can even the best rock ID question.
That said, there are reasons that we might want to continue to close questions related to agriculture.
Questions on agriculture are even more boring than are questions about rock identification. Note very well: I wrote the above with my tongue deeply impaled in my cheek.
There are other stackexchange sites that can answer some questions related to agriculture. The Sustainable Living and Gardening & Landscaping SE sites certainly have some overlap with regard to agriculture; the former even has an agriculture tag. Perhaps more surprising, the Geographic Information Systems also addresses some agricultural questions; this site also has an agriculture tag. Of particular interest is that the GIS SE site has a number of questions (with answers!) regarding precision agriculture.
We don't have the expertise to answer such questions. This might well be the real reason. If that is the case, we should admit this short falling. But note very well: Taking this route is a self-fulfilling prophecy.
Regardless of the outcome of the discussion, the agriculture tag is in need of refinement. The refinement is simple if the end result of this discussion is that all questions related to agriculture are off-topic.
If the decision is that some questions related to agriculture are on-topic but others are off-topic, good luck coming up with a rationale. Whether a question related to agriculture is left open or has been closed as off-topic has been highly capricious. Closing a question as off topic that integrates multiple aspects of the Earth Sciences (which is exactly what precision agriculture does) seems a bit ... odd.
Other aspects of this site are it's diversity: meteorology, geology, oceanography, geophysics, seismology, ecology, environmental science, climate, glaciology, atmospheric science, hydrology, soil science, ... We have a significant number of members, but compared to other SE sites, only a small number are very active.
As to whether the question What is real impact of Precision Agriculture? is on topic, what is the earth science element to the question? I'm quite prepared to vote to re-open it, but is " ... whole farm management with the goal of optimizing returns on inputs while preserving resources ..." really about earth science, or is it about anthropogenic changes to the earth (farming) and its benefit to humans? Convince me which fork in the road I should take.
¹Of all the agricultural questions across the network, the Judaism site is second only tho Worldbuilding in number of questions.