关键词: 口虾蛄, 口虾蛄, 性腺指数, 繁殖力, 早期发育

Abstract: This paper expound the measures of America to guarantee qualified successors in agriculture by legislation on series of Acts such as “Morrill Land—Grant College Act of 1862”, introduce the policies and measures to support the cultivation of beginning farmers and ranchers in 2013 farm bill, and put forward suggestions to the cultivation of new type professional farmers: highlight the dominant position of government, accelerate the progress of legislation on cultivation of new type professional farmers, insist the cultivation paths which combined cultivation with attraction, strengthen the foundation status of education and training in the cultivation of new type professional farmers.