印度梨形孢真菌对内蒙沙土紫花苜蓿幼苗生长的影响

以紫花苜蓿、印度梨形孢和内蒙沙土为试材,采用光照培养方法,研究在内蒙沙土中加入印度梨形孢对紫花苜蓿幼苗生长的影响,以期提高紫花苜蓿幼苗在内蒙沙土中的存活率。结果表明:印度梨形孢在紫花苜蓿幼苗根部成功定殖,增强了紫花苜蓿幼苗抗逆性,显著促进幼苗的生长发育。印度梨形孢在紫花苜蓿根部定殖率为85.8%;CR处理比CK的株高、地上部鲜质量、地上部干质量、根长、根鲜质量、根干质量、游离脯氨酸含量分别提高25.09%、43.18%、22.22%、17.25%、21.57%、28.57%、4.07%,丙二醛含量降低16.05%;CP处理比CK的株高、地上部鲜质量、地上部干质量、根长、根鲜质量、根干质量、游离脯氨酸含量分别提高27.55%、29.55%、33.33%、21.98%、25.49%、57.14%、77.65%,丙二醛含量降低20.83%;PR处理比CK的株高、地上部鲜质量、地上部干质量、根长、根鲜质量、根干质量、游离脯氨酸含量分别提高23.74%、86.36%、77.78%、38.13%、47.06%、71.43%、83.43%,丙二醛含量降低26.04%。

Estimation of Sand Transportation Rate for Fixed and Semi-Fixed Dunes Using Meteorological Wind Data

Taibus County, Inner Mongolia, China, lies in a farming-pastoral ecotone, where severe wind erosion and various aeolian sand hazards are prevalent and fixed and semi-fixed sand dunes occur frequently. This study was conducted to investigate the relationships between sand transportation rate and wind speed for the fixed and semi-fixed sand dunes based on field measurements. The annual quantity of soil erosion by wind was estimated using meteorological wind data. The results indicated that the sand transportation rate in Taibus County in 2000 was 57.38 kg cm-1 year-1 for the semi-fixed dunes and 4.56 kg cm-1 year-1 for the fixed dunes. The total duration of erosive winds covered 12.5% of the time of the year, and spring posed the highest potential of sand transportation. Wind with low speed (≤ 17 m s-1) and high frequency plays a dominant role in sand transportation, while strong wind (≥ 17 m s-1) with low frequency significantly enhanced the sand transportation. Erosive wind speed, directions, and frequency were three crucial dynamic factors influencing sand hazards in the farming-pastoral ecotone. The dominant factors intensifying sand and dust storms in Taibus County might be related to the favorable wind condition in combination with the durable drought, which led to land desertification and vegetation degradation.