Deep tillage reduces the dependence of tobacco (Nicotiana tabacum L.) on arbuscular mycorrhizal fungi and promotes the growth of tobacco in dryland farming

The traditional shallow tillage method reduces soil quality and affects the efficiency of agricultural production. Using conventional rotary tillage (12 cm) as the control, Yunyan 87 as the test variety, and paddy soil as the test site, we studied the effects of deep tillage (subsoiling 30 cm) on soil nutrients, arbuscular mycorrhizal fungi (AMF), and tobacco (Nicotiana tabacum L.) growth. The results showed that deep tillage increased the content of organic carbon, available phosphorus (AP), and available potassium (AK) in the 20–40 cm soil layer. The AMF community was also affected by deep tillage. Glomus, the dominant genus in both groups, increased significantly in soil after deep tillage. The AMF colonization rate was lower than that of conventional rotary tillage. Deep tillage was beneficial for tobacco growth in the middle and late stages. The root growth and nutrient content of the tobacco plants increased. Deep tillage significantly improved the output value of tobacco plants. Deep tillage is conducive to improving soil fertility, promoting the vigorous growth of roots, reducing the dependence of tobacco on AMF, and promoting the high quality and yield of tobacco in the drylands of Hunan.