Research On The Influence Of Moisture And Physiology Growth Of Populus Euphratica And Haloxylon Ammodendron And The Law Of The Water And Salt Movement Under The Salt Water Irrigation Comditions In China

The arid and Semiarid Areas in China, it is using the salty water irrigation of salt-tolerant desert plants, Populus euphratica and Haloxylon ammodendron, that can alleviate agricultural water and ecological water between reciprocal striking contradiction, and improving the artificial afforestation survival rate, and maintaining ecological water use fully supply, the influence of moisture and physiology growth of Populus euphratica and Haloxylon ammodendron and the law of the water and salt movement in the sand soil under the salt water irrigation comditions was studied by test-pit experiments,the results show that:(1)The total water consumtion of the 3 ages Populus euphratica and Haloxylon ammondendron is respectively 580.34mm～694.16mm 477.63mm～655.42mm, and its average value is respectively 644.02mm,581.66mm in the salt water (1.2g/L-12g/L 1.2g/L-15g/L).These two plants are centralized on water consumption in June,July,Augest. its total water consumption of water compared with 72.7% and 75.4%.Compared to the water consumption on the two plants, the former on water consumption is more than the latter in the whole growth stages, and the tolerance to salt of Populus euphratica is inferior to the Haloxylon ammondendron, therefore, the artificial afforestation should be prior planting the Haloxylon ammondendron.(2) Under salt stress conditions, the relationship of the growth increment and water consumption of Populus euphratica and Haloxylon ammodendron is accord with the logarithm model. The curve relationship of monthly relative growth and growth days of the basal diameter,height and new branches length of Haloxylon ammodendron is accord with the cubic polynomial model. Populus euphratica and Haloxylon ammodendron in salt stress is grow good in the early June and the middle of July, after July end, its growth become slow by salt stress, the leaf of Haloxylon ammodendron below canopies suffered damage, leading to the leaf dead and dropped in high salinity treatments. Their growth is nearly stopping in September.(3)With increasing the irrigation frequency, Populus euphratica physiological stress intensifies, and leaf chlorophyll content decreases, and photosynthetic rate drops.As the irrigation water salinity is 9g/L, photosynthetic rate dropped significantly, but at the same time, water use efficiency of Populus euphratica is improved.It fully shows that the Physiological Characteristics of salt resistant plant of high water use efficiency under adverse circumstance.The contents of stress physiology index, Pro and MDA, are increasing significantly, and the more heavier irrigation water salinity is, the more contents of Pro and MDA is in the Populus euphratica leaf. (4) Chlorophyll fluorescence parameters value, that is Fo,Fv,Fv/Fo,Fv/Fm, is generally decline on the Haloxylon ammodendron.After the Haloxylon ammodendron was irrigated with the salt water.it is decreased to some degree in the whole growing seasons. As the water salinity for irrigation is 1.2g/L-6 g/L, these parameters value is decreased slowly, as in 9g/L-15g/L, they showed the decline sharply.Compared to these initial value, Fo,Fv,Fv/Fo,Fv/Fm value is respectively decreased for 34.0%,40.9%,19.7%,8.2% in the most largest falling range.This shows that it is disadvantageous for physiology and growth of Haloxylon ammodendron under salt water irrigation more than 9 g/L.(5) Irrigated soil water redistribution was divided into three areas in the point water resources conditions:the water-rich regions that is far from dripper about 0-15cm,the water transition zones in the dipper about 15-30cm,and the water-poor regions that is far from dripper about 30-45cm. Soil profile moisture small differences exist in distance from dipper 15cm or 30cm soil range within the scope of brackish water (1.2g/L-6 g/L).(6) After irrigated the soil, surface soil (0-5cm) salt of horizontal 0-45cm range is sharply increase along the dipper to distance, the total salt of vertical soil layer also present different degree of incremental in the 0cm-200cm soil range, and the soil deposited number have the positive correlation with the irrigation water salinity, the soil total salt increase is not more in 0-100cm range, but increase is much more and the contents of total salt is bigger in the 100-200cm soil layer, that salt accumulating is obvious in deep soil.