וְהָיָה אִם לֹא תִשְׁמַע בְּקוֹל ה' אֱלֹקֶיךָ וגו' (כח, טו)
And it will be if you do not listen to the voice of Hashem your G-d... (38:15)
The Tiferes Shlomo says that the reason we recite the tochacha at this time is as a sign that the year and its curses should come to an end. If, Heaven forbid, a bad decree was issued against a person, we hope that it will be fulfilled by reading from the Torah about bad things, and he will then be able to experience only good.