| 其他摘要 | According to the grain problem which has long puzzled the Loess Plateau Region, the
article developed the research of grain production and grain safety for two large
geomorphologic regions which were the loess hilly-gully region and loess gully region in
the Loess Plateau Region, analyzed the trend and influencing factors of grain production,
studied the changes of grain production ecological cost in different spatial and temporal
scale, to predict grain productiviy in different temporal scale, studied the changes of grain
safety of t in the Loess Plateau Region in different spatial and temporal scale, in order to
solve incoordination between ecological environment and economic development in the
growth process of grain production and agricultural development, to impove the subject
research system, and to promote the sustainable development of grain safety and social
economy in the Loess Plateau Region. The main research results as follows:
(1)The grain production of the Loess Plateau region influenced by population, grain
area, climate and policy had a stage fluctuation increasing trend. The grain production of
Ansai County in loess hilly-gully region could be divided into three phases from 1949 to
2009. The first stage was from 1949 to 1974, the second stage was from 1975 to 1989, and
the third stage was from 1990 to 2009. The average grain productions of three stages were
1.89×10 4 tons, 3.72×10 4 tons and 6.1×10 4 tons respectively. The grain production of
Changwu County in loess slope-gully region could be divided into three phases too from
1949 to 2008. The first stage was from 1949 to 1970, the second stage was from 1971 to
1980, and the third stage was from 1981 to 2008. The average grain productions of three
stages were 2.67×10 4 tons, 3.86×10 4 tons and 4.95×10 4 tons respectively.
(2)At county scale, the ecological cost of grain production was increased nearly three
times, from to 8.8726 million yuan in 1950 to 30.9815 million yuan in 2010 at Ansai Count
y of Loess Plateau Gullied-hilly; Comparison of Changwu County of Loess Plateau Gully, it was increased nearly two times, from to14.6102 million yuan in 1950 to 30.5886 million
yuan in 2008. For watershed scale, the ecological cost of grain production was reduced
from to 248,600 yuan in 1978 to 55,200 yuan in 2003 at Zhifanggou watershed of Loess
Plateau Gullied-hilly; Comparison of Wangdonggou watershed of Loess Plateau Gully, it
was reduced from to 138,600 yuan in 1986 to 96,000 yuan in 2005.
(3)In the county scale, the moving average period of the grain yield in Ansai County
of loess hilly and gully region is 20 years. It is predicted that the average productivity will
be 70600t by 2019. The moving average period of grain yield per hectare is 15 years. It is
predicted that the grain yield per hectare will be 2.342.34t/hm 2 by 2019.The moving
average period of the grain yield in Ansai County of the Loess Plateau is 25 years. It is
predicted that the average productivity will be 53100t by 2018. The moving average period
of grain yield per hectare is 25 years. It is predicted that grain yield per hectare will be
3.86t/hm 2 by 2018. For watershed scale, the moving average period of grain yield per
hectare is 15 years, and the grain yield per hectare will be 5132kg/hm 2 by 2016.
(4)Long-term fertilization could improve wheat yields, and combination of N, P and
manure increased yields largest, which were 144.58%、209.29%、247.54% in three
different precipitation years. The contribution rate of fertilizers to wheat yields were
ranked as: NPM>NM>NP>PM>M>N>P, and The contribution rate of fertilizers to wheat
yields was higher in wet year than that in drought and normal year. The fertilizer
interaction of N and P fertilizer was highest, which was 1906.95kg/hm 2 , and the next was
N, P and M, which was 823.16 kg/hm 2 . Fertilizers cooperating application could make
wheat yields fluctuation in a high level, and the reason mainly come from the change of
precipitation. Amount of fringe and weightiness of thousand grains were higher in wet year
than that in normal and drought year, and the amount of fringe, grain of fringe and
weightiness of thousand grains of combination of N, P and manure were highest in three
different precipitation years.
(5)As to the comprehensive value of food security, in the county scale, the food
security evaluation grades of the Ansai county in loess hilly and gully region, and of the
Changwu county in loess gully region, both have experienced the change from poor to
good; in watershed scale, the food security status of Zhifanggou watershed in loess hilly
and gully region in 2003 was in the middle grade, and it of Wangdonggou watershed in
Loess Gully Region rose to good in 2005 from above the average (upper-middle-class/ the
high middle grade) in 1986. |
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