Yellow soil, predominant in the southern regions of China, constitutes 28% of the nation's cultivated land. Exploring the regulatory mechanisms of biochar on nutrient levels and key enzyme activities in yellow soil holds significance for soil health restoration and food security. This study investigated the effects of different amounts and frequencies of biochar application on yellow soil nutrients and enzyme activities. The experiment involved two biochar application frequencies： ① a once'application amount of biochar at rates of 5 （B5）, 10 （B10）, 20 （B20）, and 50 （B50） t·hm