Research On Characteristic Of Agro-Environmental Geology And Its State Assessment System Of Loess Plateau Area

Development and prosperous of human being's agriculture civilization is also a process of increasing occupying of mankind's agricultural active to the amount and degree of agro-geology environmental factors. In this process, agro-environment geological(AEG) system which is formed by mankind's agro-active and agro-geological environment expand continuously and its content enriched rapidly. And this, agro-environmental geology is aim at agro-environment geological system's construction, state characteristics and developing rules.The discipline refer that all agro-environment geological problems, in eluding drought, soil and water errosion, farmland sandyfization and salifization and agro-geological calamities are caused from the incoordinate between two sub-system, agro-geology environmental system and human agricultural active system, of agro-environment geological system. According to their nature, these problems can be divided into two types, one type comes from meeting with "bad" geological factors during agricultural exploit, is named original agro-enviroment geological problem. The other, oringinated from human being's improper action, which leading to bad geological phenomenon that is hidden or taking place in a limited scale, happen in a large scale, is named second-hand problem. At any region, developing process of AEG system always follow below way, that is, from natural state to man-made state, finally into choax state. There are two boundary points in this process, the first one is a demarcation point of mankind agricultural action use all kinds of agro-geology environmental factors thoroughly and reasonable, making system going to dissipatation stablize state. The second demarcation point means, mankind's agricultural action disturb some region's agro-geology environmental factors execissively, making system going to break and will fell into a state of choax.Loess Plateau Area is the original place of agricultural civilization in North China. This paper divide its historical development process of AEG system into Xiashang West Zhou, ChunQiu zhanGuo, Qin and west Han, Sui and Tang, Song Liao Jin and west Xia,Yuan and Ming, Qing and Pre-liberation, seven periods, then, discussed developing situation and related AEG condition of this area in different periods. We suppose, AEG system of this area followed a same developing trail as former one. The system showed its reback way through increasing frequency, more complex type of AEG problems. State of the system go near and near to a demarcational value point related with certain productive level.This paper advances a new train of thought: to express the process with information entropy theory. It is: to a certain area with clear graphical boundary like Loess Plateau Area, the factor and every factor's specific classification of its AGE system are certainty, so the essence of mankind agricultural action's expanding is presented as increasing its occupying rate to those factors and factors' specific component parts of it. When mankind's agricultural action go into a place with rather great environmental capacity and occupied more component parts, less AEG problems taking place, AEG condition is rather good. But when this kind of action come to a place with rather weak environmental capacity or occupy more this kind of component parts, more AEG problems appear and AEG condition become worse. Thus we find, development of AEG condition of Loess Plateau Area can be described with occupying proportion that mankind's agricultural action (taking distribution of agricultural and pastrol area as index) to agro-geology environmental factors and their component parts. Naturely, occupying rate equal to square proportion that all kinds of agro-geology environmental factor's component parts be included into distribution of agricultural and pastrol area during a certain period. By this way, classical conception of information entropy find its farourable condition.Aimed at favourablity for agriculture and stock raising, with the Analytic Hierarchy Process,...