Environmental Change And The Choice Of Crops

This paper focuses on the Tang and Song dynasties,the ecological environment in Hebei plain and rice discussed the situation,based on the believe that rice with high yield and can make use of advantages of low-lying and saline-alkali soil unsuitable for dryland,prompted the ancients efforts are not suitable for rice-growing plain of Hebei province plant rice,and ecological and environmental constraints,made in rice technology adaptation.The Tang and Song dynasties,the ecological environment in Hebei plain began to change greatly,largely shift from warm and wet to cold and dry climate,worsening water environment,scarcity of water resources,made a less desirable species in Hebei plain rice,rice cultivation has declined.The first chapter mainly inspects the hebei plain rice environment selection and rice technology improvement.Compared with upland crops such as corn,wheat,rice per mu yield not only high,and has the characteristics of water and salt tolerance,can make full use of low-lying saline-alkali land,in the hebei plain is unfavorable and dry,so the ancients have been trying to grow rice in the hebei plain.To ease the restrictions on rice growth,ecological environment on the rice production technology of adaptive adjustment,mainly include seed sprouting,adjust the water temperature response to low temperature measures,such as raising seedling transplanting,roast field water saving measures.The second chapter mainly inspects the tang and song dynasties of the hebei plain rice cultivation situation and change.Tang and song dynasties of the hebei plain rice cultivation mainly concentrated in the southern taihang mountain and bosom,who regions and the yanshan south of deep and remote thistle north,two regions of rice is stable;Central taihang foothill I and other places to places such as the east cangzhou line in some period,rice,and starts,is not very stable.Overall,tang and song dynasties of the hebei plain rice cultivation in the wane,both capital city area to the jin business core and natural condition good bosom,who states,other areas have no large area of rice.The third chapter mainly analysis from two aspects of climate and water environment in hebei plain rice planting change during the period of tang and song dynasty's environmental constraints.In the tang and song dynasties began to large changes in hebei plain ecological environment,climate warm wet to person,the continuous deterioration of water environment,lack of water resources gradually.Lower temperature directly affect the production of rice,also make it significantly increased the frequency of chilling injury;Climate change do water shortage make rice water requirement cannot guarantee.Under the dual role of climate and water environment change,the hebei plain rice cultivation gradually decline.The fourth chapter will tang and song dynasties hebei plain rainfed condition compared with rice planting of wheat and barley.In contrast to the condition of the rice,wheat "JueXu lack" advantages of subjective motivation and keep moisture drought control as the core of the wheat planting technology improvements,with the development of wheat and barley grown.Tang and song dynasties of the hebei plain rice,wheat planting is the process of"shift".Conclusion points out that the choice and change of crops is seeking human ecological environment properties and crop physiological characteristics best combination process,also is constantly adjust process between human and ecological environment,and the ultimate goal is to obtain more material survival data.