| Soil salinization is one of the key problems that needs to be solved globally.The unique wetland ecological environment of aibi lake wetland national nature reserve and the resourcerich lakes make it a natural gene pool.However,in recent years,due to the unreasonable utilization and development of human beings,soil salinization in aibi lake is serious.In addition,the uneven distribution of water resources in the arid area makes soil salinization more serious,which affects the plants growing here,biodiversity and ecological environment.Halophytes can effectively reduce the soil salt content,loosen the soil,alleviate the disaster of salinization,and restore the degraded ecosystem.Therefore,it is of great significance to study the correlation between halophytes hyperspectral spectrum and different water and salt conditions as well as the suitable water and salt environment for growth.Hyperspectral remote sensing monitoring technology has been widely used,especially in response to changes in plant physiological parameters.Plant physiological indicators change in response to spectral reflectivity after being stressed by environmental factors,so plant spectra can be used to monitor environmental changes.It is of practical significance to study its growth condition under different salt conditions and find out the suitable salt threshold for the targeted improvement of saline-alkali land.Combined with the hot issues such as drought and soil salinization in the context of current climate change,this paper investigated the water,salt and spectrum of plants in the field,assisted the water and salt control experiment,and analyzed the influence law of soil water and salt background on the spectrum and growth of plants,and came to the following conclusions:(1)there were differences in soil moisture content and soil salinity in aibi lake reserve in May and August.Soil moisture in May was higher than that in August,and soil salinity in August was higher than that in May.(2)white thorn,tamarix chinensis and ammodendron ammodendron are species with large adaptability span in the protected area.When the soil moisture content is more than 10%,only salt-ear trees grow.(3)in the estimation model of soil water and salt in arid areas,the modeling effect of spectral transformation is greater than exponential calculation: the optimal estimation model of soil salt is(1/R)"model R2=0.6661 under the transformation;The moisture estimation model is the optimal model under the transformation of(1/R)",and the fitting accuracy R2=0.5397 of the measured and predicted values.(4)the soil salt to 40 g/kg,not suitable for growth of salt alkaline,under the condition of water condition for 15% of the water,the salt content of the optimum growth conditions of 20 g/kg,under the rest of the moisture gradient,the growth state of the salt content of the best conditions for the control group(2 g/kg),SPAD,plant growth rate and negatively correlated with soil salt overall trends,trends not obvious correlation with soil moisture and red edge position in 10 g/kg redshift is the largest.Through the comparison and analysis of spectral characteristics of halophytes under different water and salt conditions,this paper discusses the most suitable growth environment,which is intended to provide scientific data for the restoration and reconstruction of vegetation in wetland area,and for the improvement,management and development of regional ecological environment. |
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