| Under the background of poverty alleviation work of characteristic industries in"three States and three districts" deep poverty-stricken areas in China,how to match appropriate crop production according to local agricultural resources to promote regional economic development,while protecting the sustainability and restoration of fragile habitats has become a focus of attention.Comprehensive analysis of the ecological characteristics and socio-economic conditions,and fully understanding the habitat advantages of the production areas have important theoretical and practical significance for guiding the construction of high-quality grape bases with geographical indications for wine production.The plateau barrier of the "low latitude and high altitude" of the Yunnan Plateau is considered to be an inappropriate area for grape cultivation,Deqin County lags behind the development of regional economy and agriculture due to the restriction of resources and environment in less land and poor irrigation conditions.However,in the dry valley area of Deqin County,there has been nearly 100 years of wine grape planting history.Deqin has developed rapidly as a new production area with a plateau characteristic agricultural industry in the past decade.However,there has been no systematic study on the environmental characteristics,ecological conditions and socio-economic impacts of this new production area.In order to reveal the zonal natural conditions and explore the advantages and disadvantages of local habitats on grape growth,this study analyzes the distribution characteristics and spatial pattern of topographic factors,land factors and climatic factors in Deqin County;the gradient changes of habitat conditions in the dry valley are studied from the local scale of the grape industry belt;the characteristics of environmental elements in local habitats are refined from the perspective of species niche,and the differences and particularities between local habitats and other regions are compared;the impact of grape cultivation on land use and agricultural structure in the producing areas was explored from the perspective of socio-economic.The study mainly got the following results:(1)The topographic factors in Deqin County are characterized by the types of alpine canyons with high elevation and large slope degree.Among them,the area with elevation>3300m accounts for 65%,the area with slope>25°accounts for 67%,the average distribution of 8 slopes leads to the higher degree of underlying surface fragmentation..The vertical distribution of land factors and climate factors along the elevation is obvious due to the vertical zonality.The macro distribution pattern is that the temperature decreases gradually along the vertical gradient while the water increases gradually along the vertical gradient with a significant seasonal variations in wet and dry seasons.Regional differentiation based on topographic characteristics:alpine region,valley Region.alpine region with an elevation>3300m,and land type is mainly natural cover type,which shows homogeneous distribution of woodland,grassland and snow area;the soil type is dominated by brown coniferous forest soil and black felt soil.The ratio of water to heat is "wet and cold",i.e.The temperature=-6.9?-6.4?,the precipitation=667mm?1517mm,dryness=30?41.7;valley region with an elevation<3300 m,and the land type is mainly human productive use type,showing fragmented and scattered distribution of cultivated land and residential areas,the soil type is dominated by brown soil,and the ratio of water to heat is "dry and warm",i.e.,The temperature ranges from 15.9? to 17.8?,the precipitation=390mm-667mm and the dryness=18.3?30.The characteristics of agricultural resources are characterized by the scarcity of land resources and scattered distribution;the variability of climate resources is obvious and concentrated distribution.(2)Lancang River valley and Jinsha River valley are the main landscape types where are the northernmost part of the arid valley in Yunnan Province with the highest altitude and latitude.Climate conditions are dry-warm valley type with secondary and transitional characteristics.The imbalance of water-heat ratio shows that the annual average temperature ranges from 15.9? to 17.8?,the hottest monthly average temperature ranges from 23.9? to 25.2?,the coldest monthly average temperature ranges from 8.6? to 13.0?,and the annual radiation ranges from 49009.3 W.m-2 to 52900.3 W.m-2,annual precipitation ranged from 375mm to 516mm,the annual precipitation concentrated in July and August,and the monthly average precipitation ranged from 46mm to 108mm,soil properties belongs semi-leaching soil in semi-humid warm temperate zone,mainly cinnamon soil type,with weak alkalinity or alkalinity in pH.The horizontal transition and vertical zonality of environmental factors in the valley are obvious,and precipitation and temperature decrease gradually from southwest to northeast along horizontal latitude and elevation;soil organic carbon,total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,available phosphorus,available potassium increase gradually with elevation.The arid valley environment meets the habitat requirements of wine grapes,which are light-loving,drought-tolerant,cold-tolerant,barren soil-tolerant and adaptable.(3)Plant communities in arid valleys exhibit prominent xerophytic characteristics,which is dominated by "Com.Bauhinia brachycarpa var.microphylla-Sophora davidii"and"Com.Vitex microphylla-Bauhinia brachycarpa var.microphylla".The appearance of the community showed a sparse and dwarfed semi-desert state,and the xerophytic ecological characteristics of dominant species are remarkable with monotonous hierarchical structure.The species composition is mainly temperate and pan-tropical at genus level,with the character that the tropical component is excessive to the temperate component,and the species diversity varies significantly vertically.Some species,such as Pistacia weinmannifolia,Jasminum nudiflorum var.pulvinatum and some genera,such as Osyris and Rhamnus,have the same composition as hard-leaved shrubs with the similar community structure,physiognomy and flora to those of the Mediterranean vegetation.It is similar and closely related to the habitats of traditional Mediterranean grape producing areas.(4)Vitis heyneana and Vitis betulifolia are two germplasm resources distributed in the Deqin arid valley area,and there are primitive niches of Vitis plants.Temperature variability is the dominant factor of grape niche distribution in arid valley,Which Isothermality and Temperature Seasonality are the significant influencing factors.Environmental factors meet the requirements of high-quality grape cultivation and have quantitative development potential.The Caloric condition is expressed as follows;effective accumulated temperature in growing period=1789?,the hottest monthly average temperature=22.1?;average temperature in growing season=19.4?;photothermal coefficient I(Rt)=3.2;frost-free period=208.3 days.The water conditions is expressed as follows:annual average precipitation=429mm;growing season precipitation=321.3mm;mature season precipitation=166.7mm;dryness(DI)=1.4.The ecological advantages are expressed as follows:the extreme difference of temperature is gentle(-6?-30?),but the seasonal variation is obvious(TS=54.11),which is the heat habitat advantage of grape growth in this region without measures for burying soil in winter;the higher dryness level(DI=1.4)and the lower rainfall(429 mm)are the water habitat advantage of long fruit hanging period and sufficient accumulation of sugar.Vertical difference of elevation and fragmentation of underlying surface are the main factors restricting large-scale cultivation of grapes in production areas.(5)Grape cultivation has a direct impact on land use change,which is reflected in the change of planting types within cultivated land,and the overall pattern of land resources distribution has not changed significantly.The indirect impact on local social and economic changes is reflected in the changes in agricultural structure and livelihood patterns.The agricultural pattern has changed from extensive agriculture based on natural resources to market-oriented commercial agriculture.The level of aquaculture has declined,and the composition of agriculture and animal husbandry has gradually disintegrated.The polarization development of livelihood patterns in grape-growing and non-grape-growing areas means that the relationship between human and land tends to simplify and the stability gradually decreases.Grape planting areas show a change from traditional grain-based planting mode to single grape planting mode,and the economic income is mainly grape planting income,which leads to increased market risk;non-grape planting areas show a degradation migration mode in mountain areas with the labor force and income structure transfer to non-agricultural activities.This study reveals the zonal characteristics of Alpine Canyon environment in low latitude and high altitude grape production areas,deepens the understanding of the habitat gradient pattern of arid valleys in industrial zones,provides systematic regional environmental background information and habitat suitability data support for the development of grape industry and cultivation in plateau area,and provides a case for the change and response of mountain economic development and agricultural industry adjustment in Tibetan areas.Meanwhile,effective suggestions are given on further scientific development and rational planning. |
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