Study on limited irrigation and N fertilizer and DPC regulation for yield effect of cotton

Based on the experiment of limited irrigation in the plot which was surrounded with plastic film towards 1．3m of underground，limited irrigation，N application and DPC regulation were comprehensively studied in the field by rotational regression design．and the model of effect of three factors on lint yield was established．Through simulation and selection，the optimum agronomic measure for lint yield≥ 1875kg／hm² was obtained，i．e．the amount of irrigation，N application and DPC regu lation was 678．8～ 821．4m³ ／hm² ，285．9～ 363．4kg／hm² and 45．8～ 51．3g／hm² respectively． Acco rding tO the optimum growth mod el，the optimum model on proportional development and the quantitative standard for practice ex-aminat~n were achieved by selected combination program ．