The Introduction Of The American Black Walnut And The Research Of Its Grafting-Cultivation Techniques

The American black walnut is a kind of native North America tree species, which has the combination of using its timbers and fruits, it has wide distribution which stretches across four to eight climate zones, it also has strong adaptability to the ecological environment,and therefore it can carry out a series of cultivation experiment in most countries in the world. In addition, the American black walnut,owning enormous economic value, is one of the main power to push many countries to introduce successively in the world, it contains multiple economic value(such as fruit use, material use, ecological value, etc.),which directly ignited the enthusiasm and vitality of the other countries ro introduce black walnut. In fact, the American black walnut introduction doesn’t happen overnight in our nation, since 1984,our country has begun to carry out cultivation experiment with the American black walnut in Henan, Beijing,Shandong, Shaanxi, Shanxi, Ningxia, Guizhou, Jiangxi, Jilin, Gansu, Xinjiang and other regions. After decades of depth studies and field research, althouth our country has been made some achivements in the aspect of the introduction experiment of the American black walnut, there are lots of problems and deficiencies in the practical process of cultivation. This paper is mainly based on the introduction experiment and result analysis of the American black walnut which many scholars are devoted to for many years, analyzing the introduction experiment of the American black walnut and its present situation in our province, adopting cultivation techniques for high grafting between the American black walnut and general walnut, even breeding of Zhonglin 1,Zhonglin 3,Zhonglin 6, Xiangling, Liaohe 1 and Qiangtele as grafting walnut varieties to carry out the studies of grafting experimental cultivation, so as to realize its economic utility and ecological value for the American black walnut and general walnut in our country. The main body of this paper is divided into three parts, the theory exploration of the American black walnut’s introduction, the practical studies of the American black walnut’s grafting and the development prospect of high grafting cultivation techniques, the first part is related to the resource provenance and distribution situation of the American black walnut, its botany characteristics and biological characteristics, its economic values and ecological benefits, the process of the American black walnut’s introduction and the current situation of the American black walnut’s development in our country, its existence questions,countermeasures or suggestions of the introduction of the American black walnut in our country, and its development prospects, future expectations in our country; The second part is related to the different grafting methods between the Amerian black walnut and general walnut, researching its influences on the survival rate of genaral walnut, the growth, the crown restoration, fruit development of general walnut, even diameter at breast height of the American black walnut;the last part majorly studies the current high grafting cultivation techniques and its existing problems. There are two kinds of grfting methods, one is the high thrust leather tongue grafting, the other is big square budding, they have their own advantages and disadvantages. By improving, optimizing and promoting of the cultivation techniques of two kinds of grafting methods, they will accelerate the process of the American black walnut’s introduction in our country, what’s more, the win-win goal of the American black walnut and general walnut in combination of their timber resources and fruit resources will be realized.