Highlight any three reasons for the dramatic increase in wheat production in USA in late 19th century?

Three reasons that lead to dramatic increase in wheat production in USA are as follows
(i) Displacing the local tribes from the plains and transforming whole landscape into agricultural fields.
(ii) Burning forest and clearing the land for cultivation.
(iii) New technology like tractors, dish ploughs reaper etc helped clearing vast crease in no time.