Optimized Eco-productive Paradigm For Small Watersheds In Hilly Gullied Loess Plateau

Hilly gullied loess region,the main body of Loess Plateau,is also an eco-economic sensitive area with special landscape pattern. Being an ecological fragile and economically underdeveloped region,environment protection and economic development remain to be double tasks it expects to solve simultaneously. Small watersheds are dominant landscape units of the region as well as runoff production,convergence and sand production unit which reflecting soil and water loss rules. Small watersheds are eco-economic compound systems,embodying structure and function of economic and social activities of human being during a certain period time. A small watershed integrates climate,soil,hydrological,geological,land use and various human factors and form a complete "watershed response" system. The paper thus takes small watersheds as basic study units for optimized eco-productive paradigm of hilly gullied loess region. According its content the paper intents to expound,it can be divided into 5 parts:The first part refers to the introduction,which mainly summarize several relevant characteristics of loess plateau,including loess physiognomy,soil erosion and so on. Deep and loose loess offers favorite conditions for agricultural production,but it is also the strike for frequent and serious erosion of the region. The chapter focuses on small watershed control and management,its history,features as well as its current development situation. Being an widely accepted water conservation strategy,small watersheds management has experienced a gradual phases with its steering guidance as well as concrete measures develop and perfect,from pure water conservation to conservation and development combination,from engineering measures being emphasized to comprehensive control with engineering,biological as well as tillagemeasures. With small watersheds management and point control,ecological environment of the whole region has been greatly improved. But with the increase of population,pressures from cultivation and husbandry remains and,soil and water erosion of the region are far from under complete control. An economically and ecologically optimized ecosystem and production mechanism awaits to be build and developed.The second part give an all-around demonstration on eco-economic backgrounds of hilly gullied loess region and concluded that small watersheds are dominant landscape units that enable them to be basic for regional management and development. Ecological and economic strategies for regional development are also put forward:soil and water conservation to improve ecological environment should be first-line task the region shoulders in the new century. "Grain for Green" policy provides chances of accelerating development for the region. Maintaining food self-supporting based on an improved ecological environment;combining agriculture and husbandry in the production system;taking husbandry as pivot while selectively develop cash forest. As natural and environment factors differs greatly in the region,practices to develop second and tertiary industry to realize adjustment of regional industrial structure,which thus promote regional economic status and better local people's living standard,should be based on locational condition and act accordingly.The third part studies in detail on landscape ecological structures and functions of small watersheds in the region,including spatial physical structure and its differentiation;biological structure and balance among its components. As a compound ecological system,function and its evolvement of small watersheds has also been touched. Several landscape processes relating to functions,including biogeophisical processes,biogeochemical cycle and biogeosocial cycle have also been analyzed. Combining the third part,five principals for optimized eco-productive paradigm of small watersheds in the region have been worked out. They are:water balance and efficient utilization principle;multi-production system of agriculture,forestry and husbandry principle;locational optimization principle;ec...