Question
 How do I get rid of dallis grass in my lawn the organic way?

Answer
Sugar, sugar sugar:
No, I'm not flirting with you. LOL
That is the answer.
That is how I got rid of my Dallis grass.
I started putting sugar on my lawn, to keep the beneficial microbes alive. They enrich the soil. Weeds love poor soil, and they do not thrive in rich soil. Make rich soil and weeds will die out. When it is rich enough, they will not even come up anymore.
I haven't put anything on my lawn in about 7 years, except sugar. One pound per 250 ro 300 sq.ft. I haven't had a weed come up for the last 5 years.
Write anytime. I love helping.
Charlotte