Effect of various tillage measures on cotton verticillium wilt in drip irrigation cotton field under film

Drip irrigation technology under film is an integrated technique of advanced cultivation and irrigation in the cotton field. The effect of various tillage measures on cotton verticillium wilt and its antagonistic microorganisms was studied. The results showed that under drip irrigation conditions, with the extension of continuous cropping year, the disease severity (DS) of verticillium wilt became more and more serious, and the maximum was in continuous cropping 10 years then decreased, and the quantity change of microselerotia of Verticillium dahliae was basically identical with verticillium wilt disease index. Under continuous cropping conditions, the number of bacteria in soil presented the trend of decrease, but actinomycetes and fungi were opposite. The inhibition effect of rice-cotton rotation on Verticillium wilt was a gradual decay process in the serious disease fields, and the disease index for the fifth year after rotation restored to the level before rotation. The deep plowing (60 cm) could significantly reduce the number of microselerotia in 0-30 cm plough layer. Under the drip irrigation conditions, the antagonistic microorganisms existed in the whole cotton growth period, but the species and quantity of antagonistic microorganisms were constantly changing. Fifteen strains with high antagonistic effect were obtained by using confront culture, so as to lay a foundation for the further exploitation and application of biocontrol preparation against verticillium wilt.