3S technology (Remote Sensing,Geographic Information System,G1obal Positioning System)can acquire information quickly,moreover can manage,renew and analyze the spatial data.Its application is very extensive,has already penetrated each fields,such as environment,economy,society,etc.How to apply 3S technolegy in modern landscape patterns is discussed,as well as some existing questions at present and its prospect.
【Objective】In this paper,we studied the photo-physiological characteristics of four shrubs species from semiarid and hilly-gully loess region under different slope conditions,and the objective was to provide fundamental scientific evidence for the reasonable utilization and management to establish stable artifical grassland.【Method】We used Populus simonii,Armeniaca sibirica,Amygdalus davidiana,and Caragana korshinskii of Wuqi County,Shaanxi Province as the experiment material.The characteristics of photosynthetic,transpiration and water use efficiency of this four shrubs species were measured with Li-6400 photosynthesis systems to reveal their adaptability and differentce to different slope positions under sunny slope.【Result】The results indicated that there was no photoinhibition of photosynthesis of four shrubs species,and the non-rectangular hyperbola model could well simulate the photosynthesis-light response curves,with R2 over 0.98.The maximum net photosynthetic rate(Pnmax),average transpiration rate(Tr),light compensation point(Lcp) and light saturation point(Lsp) were the highest in upper slope under different slope positions.The significance order of Pnmax in upper slope position was P.simoniiA.davidianaA.sibiricaC.korshinskii(P0.05);and the order of middle slope position was P.simoniiA.davidianaC.korshinskiiA.sibirica(P0.05).The apparent quantum efficiency(a) of P.simonii was the highest in middle slope position(P 0.05),and the three other shrubs species between upper slope and middle slope position exhibited no significant difference.At different slope positions,the average water use efficiency(WUE) of A.sibirica was the highest in upper slope position and the three other shrubs species all were the highest in middle slope position.【Conclusion】Comprehensively considered,A.sibirica was acclimated in upper sunny slope position and P.simonii,A.davidiana and C.korshinskii in middle sunny slope position.
The influence of soil moisture on the growth,fruit shape,fruit quality and water use efficiency of greenhouse cherry tomato(Lycopersicon esculentum Mill) was studied to select the the optimum soil moisture in order to provide basis theoretical support for rational watering in cultivating process of greenhouse cherry tomato.Ruby cherry tomato was used as the object of study by five soil moisture levels(with field capacity of 40%～50%,50%～60%,60%～70%,70%～80% and 80%～90%) to measure the change rule of plant growth,fruit quality,yield and water use efficiency.The results indicated that the highest output was 6.25 kg/m2 when the most hydrates were accumulated of greenhouse cherry tomato in the field capacity of soil moisture content 70%～80% conditions.When soil moisture accounted for 60%～70% of the field capacity,every quality indicators reached the maximum: ie.Vc 652.2 mg/kg,soluble sugar 72.8 g/kg,and dry matter content 71.8 g/kg respectively.The proportion of soluble solid was 9.8% and water use efficiency in the conditions was also the largest(13.9 kg/m3).Taking into consideration of the effects of soil moisture on the growth,fruit quality,water utility efficiency and fruit yield,the field capacity of 60%～70% could be used as an ideal soil moisture indicator of greenhouse cherry tomato.
The paper divides the environmental impact of revegetation into following aspects: hydrological process, soil environment, biodiversity, soil erosion and sediment. Based on the review of past researches, the paper points out that the difference in research scales (mostly on small scales) and methods constrain the employment of the results of these studies in policy making in revegetation on large scales; and suggests possible researchh fields in the future.
The research on the fuzzy classification analysis and principal component analysis (PCA) in plant community succession in loess hilly region was reported, with the aim of probing into the feasibility of this method in plant community succession studying. The results showed that the 13 sample plots with 15 species were classified into 5 classes.Combined with time the restoration of different communities takes, a community succession series was established:Artemisia scoparia community-Leymus scalinus community-Stipa bungeana community-Artemisia gmelinii community-Hippophae rhamnoides community. This succession series is consistent with the results got by traditional ways, showing that these methods are applicable in the plant community succession studies. Moreover this method has strict mathematic meaning with simple calculation and high precision and can be operated in computer,thus improving the quantification of plant community succession studies. Therefore this method has high values in plant succession studies.
To understand the effect of the running of Shaanxi Inner Mongolia Expressway on food crops planted along the sides, we determined the heavy metal contents(Zn, Pb, Cu and Cb) in the digestion solutions of the root, stem and leaf from rice and corn. The results showed that highway promoted the accumulation of heavy metal elements in corn and rice. Compared with the CKs(crops produced where no highway extend), contents of heavy metal elements in two crops tested from two sampling sites were both over standard. This indicates that food crops planted within 100 m away from the highway are been polluted by heavy metals, which is directly related with the running of Shaanxi Inner Mongolia Expressway. Based on this, the areas within 100 m away from the highway are not suggested to cultivate food crops.
According to the actual productivities of fragile agro-ecosystems in Mu Us Sandy Land and with Yuyang District,a typical county there,as its subject,the study investigated the evolution pattern in the primary productivity,secondary productivity and the coupling degree between farming and animal-raising in typical regions of Mu Us,following the coupling theory about compound ecosystem and the energy theory and using relevant analytical methods.To draw a conclusion in agro-ecosystems coupling degree between farming and animal-raising,three phases were divided in the typical regions of Mu Us: the complementary and synergistic phase,the interaction and proliferation phase, and the equilibrium and stabilization phase.In Yuyang,it lied in complementary and synergistic phase before 1995,in the interaction and proliferation phase during 1995 to 2005,and in the equilibrium and stabilization phase after 2005.It put forward the coupling concept of agro-ecosystems,methods and countermeasures to promote the evolution and productivity of their agro-ecosystems and to optimize the arrangement of their resources in typical regions of Mu Us.
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