| The application of water retaining agent was an important way to achieve high yield of crops in arid areas and prevented thedesertification of soil. In order to study the suitable water retaining agent for the growth of highland barley in the dry land of plateau and it controled the degradation of the grassland of "black soil beach" in the eastern margin of Qinghai-Tibet Plateau effectively. We prepared the black soil based polyacrylamide water retaining agent (BE/PAM) with the black soil (BE), acrylamide (AM), N,N′-methylene bisacrylamide (MBA) and ammonium persulfate (APS), at this time, the water absorption rate was as high as 425.6%, and the water-retention rate was as high as 394.3%. Secondly, the best synthesis conditions of BE/PAM designed by three-factors and three-levels. Furthermore, the microstructure of BE/PAM was characterized by FT-IR and SEM. Finally, the effects of BE/PAM with repeated water absorption, salt resistance, pH response, sand fixation, and the activity of PPO and soil water retention of highland barley under drought stress were studied.The results showed that the water retention rate of BE/PAM as high as 338.5% after 6 times of repeated water absorption. It was suitabled for soil with the pH value of 6-9. The moisture of the soil with water-retaining agent decreased from 40.3% to 34.1% after 35 days, the content of PPO in barley increased from 2.23mg/g to 2.31mg/g, and Leaf Browning was less frequent. The wind erosion modulus of the soil planted with Thoreau was significantly reduced, and it indicated that the soil had better sand-fixing performance. Therefore, BE/PAM provided a new ideas for the sustainable development of grassland ecosystem and agroforestry in the "black soil beach" on the Qinghai-Tibet Plateau. |