Rudiment Study On Ecotypic Climatic Regionalization Of Alfalfa

Alfafa is a kind of high protein pasturage, and its development has very important meanings to increase yield of our proteinic forage and urge the transformation of our agricultural structure from the agriculture-economy binary structure to the ternary agriculture-economy-forage structure. Studies on the distribution of different ecotypic alfafa in our country have been done in order to reasonably combine ecotypic alfafa with climatic resources and decrease the climatic risk in alfafa production, thus accelerate scale and regionalization of alfafa industry. 1 .In this study, through surveys from experts, AHP means are used to select main climatic factors affecting the alfafa distribution. The order of climatic factor according to their affecting degree from hige to low is accumulated temperature above 5 ℃, the extreme lowest temperature of years, average precipitation of years and no frost period. The extreme lowest temperature of years is the main climatic factor affecting distributions of different ecotypic varieties. Referring to literatures, the Geographical and periodical seeding experiments and greenhouse experiments are used to set up index system of ecotypic climatic regionalization of alfafa.2.We decide the fit breed of each place according to the geographical and periodical seeding experiments: FD1 like gongnongyihao fits the drought-cold areas such as Changling; FD3-5 like Haygrazer, Vector, Key etc fit the Huabei area such as Beijing and Taiyuan; FD6~8 like Lobo, Durango Eclogue, Titan802 etc fit the middle and lower reaches of Yangzi river such as Zhengjiang.3.During the course of climatic ecology division of alfafa, accumulated temperature above 5℃ is used as the main index, by gradually division, the whole country is divided into 6 climatic zones, namely Northeast zone, Huanghuai zone, Yangzi river valley zone, Northwest of Mongolian zone , Qingzang altiplano zone and unfit zone of South China. In each climatic zone, based on the main and secondary indexes, the climatic zones is divided into second climatic ecology regions, such as north of Xinjiang region, south of Xinjiang region and south of Tibet region etal, total 21 regions. This result is proved to be reasonable by the means of clustering analysis, two results are basically consistent.4.By assessments on climatic resources of every region, we consider the Huanghuai region is the best region for alfafa's plantation and development and is the main base of our country for alfafa. In northeast region and Yangzi river valley region, the character of resisting cold and resisting hotness and wetness should be paid more attention especially. Part of Qingzang altiplano region can fit for alfafa plantation, but selecting adaptable variety. Whereas in northwest region, there must be irrigation for alfafa growth, and in the meanwhile should select the variety of resisting cold...