Abstract:

To study the effect of soil temperature in different soil layers on the occurrence of tobacco root and stem diseases, the annual variation characteristics of soil temperature in three ecological tobacco areas were analyzed by using the soil temperature data (including 0, 5, 10 and 20 cm soil layers) of 19 representative counties and cities (districts) in Henan Province from 2011 to 2020, and the relationship between soil temperature and the occurrence of tobacco root and stem diseases was analyzed as well with Xiangcheng as an example. The results showed that in the same soil layer at different growth stages, the ground temperature showed as followed: southern Henan tobacco region>central Henan tobacco region>western Henan tobacco region; the effect of soil temperature at different growth stages on rhizome diseases was as followed: root extension stage>vigorous period>mature stage; in different soil layers, the soil temperature of 20 cm>5 cm and 10 cm>0 cm, while the influence of soil temperature of 5 cm and 10 cm on rhizome diseases was not obvious, which was related to the number of tobacco roots distributed in each soil layer. The ecological control measures of rhizome diseases such as proper adjustment of transplanting period, film covering, film uncovering and irrigation were put forward to effectively reduce the occurrence of diseases.

Key words: ground temperature, tobacco, rhizome diseases, linear trend, grey theory