Abstract: Based on the theory of sustainable development of cotton field,effects of liquid film mulching on the growth and development of cotton roots were observed by with the methods of ninhydrin and molybdenum blue,and bidirectional soil section slicing,respectively.The study showed that mulching could quicken the growth and development of cotton roots during early growth period,which reflected in the enhanced root vigor and the root dry weight per plant.However,mulching was disadvantageous for cotton roots to penetrate into deep soil layers,and deep roots decreased quickly.Compared with plastic film mulching,liquid film mulching obviously increased the absorption and synthetic ability of cotton roots during whole growth period.The distribution of root systems in soil was comparatively reasonable,and deep roots decreased slowly,which contributed to the proportional development of cotton plants,and prevented cotton plants from pre-mature senescence.It was suggested that the application of liquid film could be a feasible technique in cotton cultivation practice.

Key words: Stipa baicalansis, Tiller, Module structure, Clonal growth