Under high ridge,plastic mulching and drip irrigation conditions,the greenhouse culture experiment with the cucumber cultivarChunqiuwangwas carried out to study the effects of different -concentration nutrient fluids on the cucumber yield and quality and the soil characters.The results indicated that in terms of plant growth and fruit quality and yield,Treatment A was significantly superior to other treatments.The EC value and pH value of the soil after treatments were not significantly different from those of the soil before treatments except the EC value of soil 0～10 cm deep between the drippers and the pH value of soil 0～10 cm deep at the drippers.It was concluded from the above results that Treatment A was the optimal concentration for cucumber culture.
The non-heading Chinese cabbage variety Aijiaohuang and Luxing were used as materials in order to study the interactive effects of substrate moisture and light intensity on plant growth and quality of non-heading Chinese cabbage.Excessive substrate moisture caused overgrowth,which was more obvious under low light density.When the substrate moisture was too low,plant growth was significantly inhibited.The contents of soluble sugar,soluble protein,VC and nitrate increased with the reduction of substrate moisture,while the contents of the previous three decreased and nitrate increased with the light intensity decreasing.The non-heading Chinese cabbage plants grew better under the stronger illumination(100% and 60%) with 80% water-holding capacity of substrate,or 60% substrate moisture under the lower light intensity(30%).
The Populus Euphratica in Tarim River Basin has important biological and ecological conservation values.Using remote sensing techniques to monitor Populus Euphratica leaf chlorophyll content for could provide rapid and timely information woodland management,resource protection and utilization of Populus euphratica.In this study ISI921VF-512 field spectral radiometer was used to measure the 393-1095 nm visible-near infrared band hyperspectral data of natural Populus euphratica leaf chlorophyll content in Tarim River upstream in growth season from June to October monthly.Correlation analysis was carried out for the leaf chlorophyll content and spectral reflectance,and estimation model of Populus euphratica chlorophyll was established based on hyperspectral indices.The results showed that in unary linear regression model,the correlation of the fresh weight chlorophyll a,b,a + b content and hyper spectral index NDVI705 achieve very significant levels,and the correlation coefficient R is the biggest in the 13 kinds of hyperspectral indices; at the same time multivariate regression model was set up by the fresh weight chlorophyll a,b,a + b content and hyperspectral indices.It provides a theoretical basis for Populus euphratica physiology and health evaluation.
Soil moisture has been considered as one of the most important indicators of soil conditions. It also is the decisive factor affecting crop growth. Accurate estimation of soil moisture in space and time is very important to understand the earth system. It also is of great significance to agricultural production and ecological reconstruction in arid areas. Two feature space parameters, NDVI and MSAVI, were established in this study. Characteristics of NDVI and MSAVI were compared. The relationship between drought index(TVDI) and soil water content was analyzed. The spatial distribution of TVDI was studied. Results showed that: dry edge fitting coefficients of Ts /MSAVI space and Ts /NDVI space were greater than 0.90; whereas fitting coefficients of wet edge were not so good as those of dry edge; dry edge and wet edge of Ts /MSAVI space were more likely to intersect; combined with soil surface temperature, the Ts /MSAVI space could represent changes of soil surface humidity well; highly significant negative correlations were found between soil water content and TVDIM, and TVDIN; spatial distribution of TVDI predicted by Ts /MSAVI space was similar to that of TVDI estimated from Ts /NDVI space.
In arid and semi-arid sandy area, strong wind-sand flow activities as one of the main environmental characteristics, has great effect on the plants, they are the important restraint factors for cotton cultivation and growth. Two groups with three replicates were set for cotton which is not affected by wind-blown sand and affected by wind-blown sand,photosynthetic parameters was determined at different growing stages of cotton, and the effect on photosynthetic characteristics of cotton was investigated. Results showed that cotton photosynthetic parameters affected by wind-blown sand were significant in the seedling stage and bud stage, but there were no significant difference in the blooming stage. Cotton leaf will be affected by wind-blown sand, with leave scar on the blade. Photosynthetic rate(Pn),stomatal conductance(Cs),intercellular CO2concentration(Ci) and transpiration rate(Tr) of new wounded cotton function leaf were significantly lower than that of the old wounds and uninjured. Dust falls have a great effect on cotton leaf photosynthesis parameters after the wind-blown sand. Unit leaf area dustfalls show significant negative correlations with photosynthetic rate(Pn), stomatal conductance(Cs), intercellular CO2concentration(Ci) and transpiration rate(Tr).
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