描述:
duction in the area is
restricted by disadvantageous natural resources and environmental conditions,
including low arable land area per capita, frequent drought events and a landscape
dominated by mountains. Forage crop rotation systems could improve soil fertility,
increase crop外eld and provide quality forage supplies for livestock production.
Additionally, their adoption is considered a suitable means to advance sustainable
agriculture development. In this study, the role and status of forage crop rotations in
Tianshui city were studied.
描述:
governors of HAN
Dynasty. The policy was carried out in most area of the west and the north. In
DONGHAN Dynasty, it also appeared in the inner area. The thesis is to tell opening
up wasteland and analyses the origin and features of opening up wasteland to get the
conclusion: Opening up wasteland in ancient times began in War times and was
developed fully in HAN Dynasty. Opening up wasteland in northwest area of HAN
Dynasty was only a comprehensive policy to defend the country, including the
content of politics
、
military and economy. It was t not for the people but for the
country. The policy was spread and lasted for a long time. In economy, it promoted
the development of agricultural economy in northwest area by bringing new tools and
ways of farming, which also joined the relationship between the central area and the
northwest. In politics, it laid a solid foundation for the unity of northwest area and the
victory against HUN. In culture, it advanced the communication and joint among
different races. Meanwhile, it was a base for opening up wasteland by troops and
common people in Cao Wei period.
描述:
isasters in China,
the earthquake caused the largest number of deaths accounted for 54% of the total
number, and 80-90% of China's earthquake occurred in rural areas.
描述:
he paper studies from the situation and feature of Agriculture
Tri-dimension Pollution in Yellow River Basin areas, and divides it into several regions according to
basin’s pollution feature by adopting the method of searching documents , research, systems analysis,
quantitative and qualitative analysis and so on, and analyzes the problem of Agriculture Tri-dimension
Pollution in Yellow River Basin areas from the view of tri-dimension and system by use of the theory of
Environmental value, Technology Value, Ecology, Circular economy , uses System Dynamics to track
dynamically the change in the future of the various variables in different modes and constructs the
system mode of agricultural tri-dimension pollution in Yellow River Basin, and simulates the system;