Study on Comparative Advantage of Plateau Characteristic Agriculture in Yunnan

To find the highlighted advantage and development space of plateau characteristic agriculture in Yunnan,using qualitative and quantitative combining methods,comparative advantage of plateau characteristic agriculture in Yunnan is evaluated comprehensively.Qualitation takes Sichuan,Chongqing,Guizhou and Guangxi adjacent to Yunnan and Southeast Asian countries which are opening focus of " bridgehead" as reference objects,while quantitation takes 32 provinces of whole country except Hongkong and Macao as reference objects,and there are 4 kinds of qualitation indexes and 6 kinds of quantitation indexes containing 44 sub-items.Results show that comprehensive comparative advantage coefficient of plateau characteristic agriculture in Yunnan is 1.55,and it has 3 kinds of comprehensive comparative advantages:diversity,ecological security and time difference complementation.The research results could provide references for agricultural development in Yunnan and other plateau regions.

Spatial pattern and mechanisms of farmland abandonment in Agricultural and Pastoral Areas of Qingzang Plateau

With the rapid development of social economy and urban−rural integration,the phenomenon of farmland aban-donment worldwide has proved to be one of the main trends of land use and land cover change(LUCC),and profoundly affected the rural landscape and regional ecological environment.Restricted by the natural environ-ment,economic development and backward agricultural technology,the phenomenon of farmland abandonment is also common in the Qingzang Plateau(QP).Therefore,this paper adopted the spatial autocorrelation method to analyze the spatial pattern of abandonment in the agricultural and pastoral areas of the Qingzang Plateau(APA−QP)in 2017,and the geographically weighted regression(GWR)model to explore the effects of geograph-ical resources,socio-economic development and location conditions on farmland abandonment.This study found that:1)From 2015 to 2017,the abandoned farmland area in the APA−QP was approximately 18.23×10^(4)ha,with an overall abandonment rate of 15.18%.On the whole,it showed the distribution characteristics of“strong in the south and weak in the north,strong in the east and weak in the west”.2)There were positive spatial correlation between both abandoned area and abandonment rate in the APA−QP,showing“concave”and“convex”patterns,respectively,mainly concentrated in the Huang−shui Valley and the Southeast Tibet;while in the western and northern regions,the degree of abandonment was relatively low.3)Farmland abandonment in the APA−QP was mainly driven by the geographical environment changes and farmers’decision−making on farmland utilization.There was significant spatial heterogeneity on farmland abandonment associated with the impact of geographical resources,socio−economics and location conditions.The geographical resource factors had a positive impact on the abandonment,and were strongly constrained by natural geographic conditions such as altitude and slope.The farmland resources in the Qingzang Plateau are limited,but are of strategic significance for the sustainable development of agriculture in the whole Qingzang Plateau.In order to realize the rational distribution of agricul-ture and animal husbandry and the sustainable utilization of farmland resources in the plateau region,land use strategies should be implemented according to regional differences and regional advantages in order to ensure the ecological environment security of Qingzang Plateau.

Preliminary Breeding of Superior Maize Combinations in Zhaotong,Yunnan

[Objectives]This study was conducted to select superior maize combinations.[Methods]With the control maize variety Haihe 2 in the middle altitude area of Yunnan Province as the control,adopting a single-factor randomized block three-replicate experiment design,a one-year field cultivation experiment was carried out in Luyin Village,Yongfeng Town,Zhaoyang District,Zhaotong City.[Results]A total of 11 new superior maize combinations including ZT-1 and ZT-2 were obtained.Through comprehensive comparison analysis with Haihe 2(CK),we selected six superior combinations of ZT-1,ZT-3,ZT-4,ZT-6,ZT-7 and ZT-9,which showed overall performance better than the control Haihe 2(CK)in terms of resistance,yield,and ear traits.[Conclusions]The selected 6 superior combinations have promotion value,and are recommended for higher-level trials and demonstrations.