咸水灌溉对沙土土壤盐分和胡杨生理生长的影响

通过咸水灌溉沙土土质生长的幼龄胡杨,分析了咸水灌溉沙土土壤盐分分布累积特点、盐分胁迫对胡杨的耗水生长关系、叶绿素、Pro、MDA的影响,结果表明:(1)在1.2—3 g/L范围内,微咸水灌溉沙土处于脱盐状态,6—12 g/L咸水灌溉使沙土积盐大增。在整个生长周期内,微咸水和咸水灌溉,0—200 cm内土体的总盐都呈累积趋势。(2)咸水灌溉胡杨,不同盐分处理的生长耗水关系可以用对数模型描述。(3)盐分胁迫下,胡杨叶片内叶绿素含量呈抛物线递减,Pro和MDA含量则呈现抛物线递增趋势。说明短期内咸水灌溉对土壤安全和胡杨的生长影响有限,可用咸水解决生态缺水现状,3种生理指标可用来衡量胡杨的盐胁迫程度,以此为指导提高人工造林的成活率。

Effect of saline water irrigation on sand soil salt and the physiology and growth of Populus euphratica Oliv.

Populus euphratica Oliv is a typical species for afforestation in xinjiang. Lots of forests have been planted for protecting the ecological environment in south of junggar basin. Yet the survival rate is strained by the scarce water resources. Populus euphratica Oliv was selected as the reaearch object in this study. The influence of salt water on the physical properties of sand soil and the physiological growth of Populus euphratica Oliv has been analysed. Under different saline water irrigation condition, we got the salt distribution and accumulation characteristics in sand soil, the relationship between the salt stress and water consumption, chlorophyll, Pro and MDA. Through analyzing the characteristic of salt accumulation in the sand soil and the physiological change of Populus euphratica Oliv under the salt water irrigation, we got the response characteristic with salt stress. This study can provide scientific basis for making full use of local salty water and improving the survival rate of afforestation. The results show that: (1)The total salt of sand soil becomes to desalt when the salt content of irrigating water is 1.2-3g/L. The salt in soil increases when the content is 6-12g/L. On the other side, whether the saline or brackish water irrigation, soil salt in 0-200cm shows an increasing trend in the whole growth period. When irrigated using saline water, the accumulation rate of soil salt increases with salinity. There is a direct proportion relationship between the soil salt accumulation and salinity. (2) Salt water irrigation can make the growth period shorten. The higher the salinity is, the shorter the period is. The Populus euphratica Oliv does not grow any longer at the end of June when irrigated with salt water of 12 g/L, and the average soil salinity reaches 13.96 g/kg at the same time. When using the salt water of1.2 g/L, the Populus euphratica Oliv is growing slowly at the end of August and the average soil salinity is 2.99 g/kg. It has little harm to the growth of Populus euphratica Oliv under the low salinity level. The relationship of growth and water consumption of Populus emphatics Oliv can be expressed using the logarithm model. It has a good agreement with the observing results in 1 g/L-6 g/L salinity. The relationship is not so strong in 9 g/L, 12 g/L salinity. The minimum of correlation coefficient is 0.7644. (3) The external form response of Populus euphratica Oliv with salt water irrigation is mainly manifested as growth indices. The inner destruction shows from the typical physiological indexes chlorophyll, proline (Pro) and malondialdehyde (MDA). The three physiological indexes have significant changes under adversity conditions. The leaf chlorophyll content decreases with parabolic, and the Pro and MDA content has a parabolic increasing trend under the salt stress. The result shows that three kinds of physiological indexes can be used to measure the salt stress level, and short-term salt-water irrigation has little effect on soil safety and the growth of Populus euphratica Oliv . Salt water is beneficial to reliving ecological water shortage. This study can be a guide to improve the survival rate of afforestation.