Nong cun- ke xue zhi shi Nong hu- ke xue zhi shi Nong ye- ke xue ji shu Er tong wen xue- ke xue gu shi ke xue zhi shi Nong cun chang yong shu xue zhi shi/ You xi zhong de ke xue he zhi shi. Ke xue zhi shi Zi ran ke xue shi zhong guo zhe xue shi