It was the practice of the Prophet (peace and blessings be upon him):
"When he (peace and blessings be upon him) prayed for rain, he would say: 'O Allah, give water to Your servants and Your animals, spread Your mercy, and give life to Your dead land.'"
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4666
Hadith Gradingالألبانی:حسن
Hadith Takhrij[د] عن ابن عمرو. المشكاة ١٥٠٦، صحيح أبي داود ١٠٦١.