The Regional Difference Of Rice Domestication Rate In Ningshao Plain And Liyang Plain And Its Explanation

China is the origin of rice farming.The archaeological discoveries as well as plant archeological evidences show that there are rice remains 8,000 years ago in the middle and lower reaches of the Yangtze River and the Huang-Huai Valleys.What can be affirmed currently is that the rice domestication in the middle and lower reaches of the Yangtze River started around 10,000 years ago,but there are differences in time of domestication completion;evidences of carbonized rice seeds and rachilla indicate that rice domestication had already been completed about 6,000aBP in the middle reaches of the Yangtze River;the evidences of carbonized rice seeds,rachilla and fan-shaped phytoliths present that the completion time of rice domestication in the lower reaches of the Yangtze River is approximately 6,000 aBP,or even later.Prehistoric humans domesticated wild rice as cultivated rice and used it for about two and four thousand years respectively in the middle and lower reaches of the Yangtze River.The reasons causing this regional variation of domestication rates remain to be further explored.Based on current mainstream theory of agricultural origin,this paper believes that the available animal and plant resources along with population scale affect people’s enthusiasm for domesticating animals and plants,the landform conditions determine the area of arable land around the prehistoric site groups,and the area of cultivated land is the significant factor influencing prehistoric human’s preference to livelihood model.By means of summarizing predecessors’ researches,this paper selects and analyzes Liyang Plain and Ningshao Plain,the typical areas in the middle and lower reaches of the Yangtze River through existing archaeological data of animals and plants,prehistoric population size,and estimation model of arable land area.Meanwhile,it restores and estimates the time-varying changes of the plant and animal resources,population size,and area of arable land around the prehistoric site groups in two areas during the critical period of rice domestication(10,000-6,000 aBP).The comparison gets the conclusions as follows:The diversity of animal and plant resources in Ningshao Plain is much richer than that in Liyang Plain,so do the scale and duration of hunting and gathering wild animals and plants by prehistoric ancestors.Compared with Liyang Plain,the livelihood models of prehistoric ancestors in Ningshao Plain are less enthusiastic for domesticating rice.The population growth rate in Liyang Plain is much higher than that in Ningshao Plain area,which sends Liyang Plain into higher population pressure.In terms of the area of arable land,the supply of Liyang Plain is much higher than that in Ningshao Plain,which further limits the expansion of rice agriculture in Ningshao Plain.Based on the comparative analysis of animal and plant resources,population size and arable land area in Ningshao Plain and Liyang Plain,this paper considers that the population pressure related models in the theory of agricultural origin are more suitable for explaining the regional differences in rice domestication rates between two regions.