Abstract: The effect of super absorbent polymer and fibers on the growth of ryegrass in simulate loam under drought stress was investigated using a potted water control method. The experiment was divided into four groups, namely the control group （without addition）, 1% fiber group, 0.3% super absorbent polymer group, and 1% fiber+0.3% super absorbent polymer group. During the experiment, samples were taken and measured on the first day as a control, and then water was cut off to start the drought stress experiment. On the 5, 10, 15, 20, 25, and 30 d of the experiment, the growth characteristics of ryegrass were observed, and the relative water content, relative water deficit,relative conductivity,malondialdehyde,soluble sugar, proline and chlorophyll were recorded. The results showed that the drought resistance of ryegrass in each treatment was in the order of 0.3% super absorbent polymer+1% fiber group, 0.3% super absorbent polymer group, 1% fiber group, control group, from highest to lowest. Compared with the control, as the number of dry days increased, super absorbent polymer alone reduced the degree of wilting and yellowing of ryegrass in simulate loam; the degree of decline in the relative water content of ryegrass was slowed, resulting in a 25.38% increase in relative water content and a 28.57% reduction in relative water deficit; reduced the rate of increase in relative conductivity and malondialdehyde, resulted in a 23.57% reduction in relative conductivity and a 14.25% reduction in malondialdehyde content; slowed the degree of change in soluble sugar content was slowed and the rate of proline accumulation was reduced, resulting in a 13.06% reduction in soluble sugar accumulation and a 45.79% reduction in proline accumulation; the degree of decrease in chlorophyll SPAD value was slowed down, resulted in a 53.68% increase in chlorophyll SPAD value. The combined effect of super absorbent polymer and fiber was better than the effect of super absorbent polymer alone, compared to the control, the relative water content of ryegrass was increased by 36.09% and the relative water deficit was reduced by 40.62%; the relative conductivity and the malondialdehyde content were reduced by 26.69% and 31.69%; the accumulation of soluble sugars and proline was reduced by 16.91% and 65.42%; and the chlorophyll SPAD value was increased by 70.59%, which further extended the survival days of ryegrass under drought stress, and enhanced the drought tolerance of ryegrass.

Key words: Lolium perenne L., simulate loam, super absorbent polymer, fiber, drought stress