The ninth blessing of the weekday Amida as recited between Pesach and the rainy season contains, in some traditions, the phrase:
ותן ברכה על פני האדמה
and give a blessing on the face of the earth
(text and translation from ArtScroll Nusach Ashkenaz Siddur, 2nd ed.)
What does it mean to give a "blessing" on the face of the earth? What is being put on the earth?
Someone suggested to me that it is a request for dew which falls in the summer in addition to the winter, though he wasn't sure why it wouldn't just explicitly say "ותן טל לברכה and give dew for a blessing".
Others suggested to me that it is a request for the produce that is in the earth to grow bountifully, though this isn't exactly giving some thing "on the face of the earth" (especially considering how that phrase is used quite literally in the rainy season version), most produce isn't really growing for much of the summer (but rather being harvested), and this seems to have been already covered by the earlier line "ברך [את] כל מיני תבואתה לטובה bless all types of [the year's] crops for good". And why "give a blessing" instead of the verb "bless" if not giving a specific object?
Do any commentators on the Siddur discuss this particular line and what it requests? How do they understand it? If the answer is one of the above suggestions, how do they deal with the issues mentioned above?