农业科学

• 收获

  The maize harvesting mechanization in china is influenced by policy, technology, economy and nature factors.

  我国玉米收获机械化受到政策、技术、经济和自然方面的影响。

• 采伐

  According to the results, the reasonable cutting, skidding and clearing method are chosen to lessen the disadvantageous impacts of forest harvesting on site soils and to protect and improve the growth capacity of site soils.

  这样才能够减少采伐作业对林地土壤的破坏，保护和提高林地土壤生产力。

• 收割

生物学

• 捕获

  In chapter 3, we give out Lotka-Volterra prey-predator model with density constraint and get the optimal harvesting policy that takes the maximum net rent as management purpose, when harvesting ability are limited or unlimited.

  第三章给出了有密度制约的Lotka-Volterra捕食者-食饵系统，当总捕获能力有限和无限时，以最大纯收益为管理目标的最优捕获策略。

• 采伐

  However, as frequent forest harvesting in a long times, makes this region's evergreen broad-leaved forest belonging to secondary vegetation types.

  但由于长期以来频繁森林采伐的结果,使得这一地区的常绿阔叶林大都处于人为干扰下的次生植被类型。

• 收获