Agricultural Diversity Of Loess Plateau In Eastern Gansu Province,China

Loess Plateau of eastern Gansu Province located in the transition zone between cropping area and nomadic area,and different types of crop-livestock integrated system has sustained from north to south.In this thesis,data was obtained from three townships,which were selected distribution Shenshe township,Quzi township and Tianshui township as a research area.Analyzing the agricultural crop production systems,livestock production systems,management and farmers system along the rainfall gradient type and temperature gradient variation.Major results as following:1.The diversity of crop production systemsFrom north to south,crop varieties gradually reduced,and the main crops were alfalfa,potatoes,winter wheat in northern,alfalfa,winter wheat,maize in central,winter wheat,corn and fruit treesin south.With the increasing of rainfall,a-diversity of crops richness and evenness index becomes smaller.The most abundant crop varieties appeared in north,where cultivated area showed uniform;there were large differences of cultivated area among different crops in central;the differences of crops acreage were small,and a-diversity index was minimum in south.?-diversity of crops suggested that there were vivid differences between north and south for planting structure,and the same proportion happened in central and south for same crop.2.The diversity of livestock production systemsFrom north to south,the proportion and number of farmers who fed sheep or goats gradually reduced,and the mainly feeding animal from sheep into goats,the number of donkey(or mule)and cattle up to the largest in the central,and the number of breeding pigs were roughly equal in three sites.a-diversity index of livestock was larger and rich,the number of breeding average was nearer in central;a-diversity index of livestock was smaller,and livestock structure was simple in south.the situation in north was betewwn south and central,?-diversity index of livestock were closer between central and south,and breeding structure were similar.The farmers of two sites fed the same number and proportion for the same livestock;?-diversity index of livestock between north and south was large,the two smaller fed the different number and proportion for the same livestock.3.Diversity managementFrom north to south,with the increase of precipitation,mainly power resources changed from the animal draught into agricultural machinery,and meanwhile manure into fertilizer.The direction of agricultural system showed from extensive of subsistence to intensive of commercialization.4.From north to south,the structure of a combination of planting production and feeding production changed into the structure of dominated by planting.This research investigated different geographical areas of agricultural production systems,and compared the differences of zonal time and biological diversity for crop-livestock production system,and reflected the relationship of agro-ecological system in Loess Plateau of eastern Gansu Province.Results can be used to explain the relationship between the agricultural diversity and climate,and provide a theoretical basis and reference to speed up the agriculture structure adjustment.