Omitting "v'ten berachah"

Hi,

During the spring and summer months, our prayer for agriculturally helpful weather in the amidah includes a request of v'ten berachah, asking Gd to send blessing upon the land. During the fall and winter, the same blessing instead says v'ten tal umatar l'vrachah, asking Gd to send dew and rain of blessing.

One who omits the request for dew and rain in their season repeats the amidah, because those are critical and they are not specified in any other part of the amidah. However, one who omits the generic v'ten berachah [without inserting the words of the rainy period] in its season does not go back, since the theme of asking Gd for agricultural blessing is stated even without those words.

(Rivivot Ephraim 1:78:1)

Have a great day,
Mordechai