On Changes Of Agricultural Production Structure In Songhua River Basin During The 20^TH Century

After a century of agricultural development, the Songhua river basin, where black soil lays on, has become a vital food production base for the country. Although this area is dire cold with short summers and long winters, the soil is enriched, and rains and warmth are in the same reason, resulting in a good environment for agriculture development. Since the "de-regulation" for the north-east China, migrants from inland China moved in over time, causing an increase of land farming as well as the tension between human and lands. With the development of agriculture in involved area, wild mountains and marshes have been turned into enriched soil, and forests become farmland and dwellings in villages, natural scenes shifted to man-made eco systems, which reflects a remarkable transition on the structure of human-land system.As the interactive interface for human society and natural environment, agricultural system’s structural changes and functional evolution forms the relationship of surface and inside, and depends on each other. Impacted by central China’s farming culture and economically influenced by globalization, the "squeezing" effect of crop farming to livestock, forestry, and fishing and hunting industries in the Songhua River basin has become more apparent over these years. Production structure gradually lateralizes and the function of agriculture system weakens, resulting in a series of environmental and social problems.Since the beginning of 20 century, the crop farming industry in the Songhua River basin has evolved from "lateralized" to "dualized" and finally to "triadic" farming structure and the agricultural system has showcased a good developing trend. The functional outcome occasionally experienced adversity, but still within the boundary of self-organisation. At the times of the Republic of China, crop farming industry system was open and efficient while during the period of Manchuria, its output was less that the input; after the founding of PRC, the system was in a status of imbalance; and after CPC central committee’s 3rd plenum, the crop planting structure was continuously optimized, and the agriculture system was developing stably and continuously.The main characteristics of the 100-year development history of livestock system is the similarity of livestock structure. In the early stages of the 20th century, the development of the livestock system in the Songhua River basin was not balanced because of the natural environmental difference in varied regions and differences among different races. In the Nenjiang River and Sanjiang River plains, non-bird domestic animals that were kept for food sources were primarily pigs, sheep and cattle while poultry sources that were usually grown for food included chickens, ducks and geese; the western prairie area of Songhua River basin was historically the area in which nomadic tribes kept their domesticated animals, and those nomads usually grew horses, cattle, sheep and dogs; the hunting tribes living in the eastern area of Songhua River basin, on the other hand, were accompanied by deer and dogs in the old times, but today that picture only appears in the memories. Since the mid-20 century, because of the racial integration and technological advancement, the regional difference of livestock structure in the Songhua River basin has literally disappeared and the ecologic system thus put at risk due to the elimination of species varieties.The Songhua River basin is the hometown for tribes in the forests. Both Russians and Japanese were craving for those lush forests. Before the founding of People’s Republic of China, forests were heavily consumed with little re-planting and maintenance, resulting in an imbalanced forest utilization structure. After the founding of PRC, re-planting and consuming were equally emphasized, the forest utilization structure of the Songhua River basin were continuously optimized, the economic, ecologic and esthetic value of forest system were also emphasized.Fishery was the traditional industry for the Songhua River basin. In the early years of the 20th century, fishery in the Songhua River basin was still a natural economy and fish resources were abundant while fish species structure was reasonable. With the increase in fishing productivity, natural fishes hunting was the dominating activity in the fishery industry. As the fishery industry was pressurized by the drastic decrease in fish resources, fish growing business began to overtake and became the more advantageous sector, with the fishing industry structure being more optimized as time passed by. At the end of the 20th century, the development of fishing species structure in the Songhua River basin tended to be multi-lateral, ecological and quality-based.The development of agricultural system and its sub-systems not only is influenced by the interaction of internal factors, but also substantially influenced by some external factors, such as culture, regulations and technology, and reversely impacts these external factors, thus forms an interactive, mutually dependable system. Reasonable economical system allows for proactivity and creativity, helps to improve the efficient use of resources, the continuous optimization of agricultural structure, and complete fulfillment of system function; technologic innovations can break the restriction of undeveloped systems and bottlenecks, and become the critical impetus and determinating factor.As the extension and functional development of human-land system, agricultural technology plays a vital part in the historic evolution of farming structure. Scale-use of equipments, such as agriculture machinery, centralized input of fertilizers, effect of breeding to the adaptive ability of creatures, and irrigation to the ecological environment of farmlands all rely on the adjustment of a certain factor (or step) in the agriculture system to improve the self-organisation function of agricultural system, so that an optimized agriculture structure and a more complete functional scheme can be achieved.As the "structure-function" dual system that has become more open over time, an agricultural system’s existence and development can be influenced and restrained by the upper-hierarquy human-land system, which is reflected by the human-land structure’s stimulating effect on an agricultural system at some times, and impediment to at other times. If human-land relationship tends to be reasonable and in balance, an agriculture system will develop appropriately with the structure optimized gradually and functions performed well; If human-land structure is profoundly imbalanced, the human-land relationship will be intensified, resulting in some warning signals-natural disasters, from the nature, which in fact provides feedback information for an agricultural system’s restore to its appropriate status, in order that the participants of an agriculture system-human beings, can make changes on the structure and thus the economy and ecological system can be highly efficient.