| The climate resource, which provide agricultural with energy and materials as light, heat, water and air etc. is one of the most important natural resources that influence agricultural production. It plays a decisive role in the types of agricultural production, planting system, layout structure, potential productivity, vision for development, as well as in the number, quality and distribution of agricultural products. As the global climate change, the production conditions of staple crops (rice, wheat, corn and soybean) are being affected, which may had a negative influence on the food security of our country.This study was based on the RS monitoring data of China’s arable land space spatial distribution, and the long time series meteorology data and soil data since 1961. The total production potential of rice, wheat, corn and soybean were estimated by using the GAZE model, the time evolution tendency of the four main types crops and the three climate factor change tendency in the late 50 years was analyzed on a regional basis, and then partial correlation method was able to be applied to analysis the effect of climate factor temperature, precipitation and radiation on the production potential of rice, wheat, corn and soybeans respectively. The results are as follows:(1) Climate change had made great impacts on main crops production potential during last 50 years in different degree. The suitable planting area of wheat didn’t change much, while the rest were increased. The suitable planting area of rice had the highest growth rate, soybean and maize comes second and third separately. The total production potential of rice showed an increasing trend, while the total production potential of wheat had a decreasing trend, and the total production potential of maize and soybean kept stable.(2) From the aspect of regional land, The total production potential of rice in the Middle-lower Yangtse Plain area changed most obviously, followly Huang-Huai-Hai Plain, other gro-ecological zones did not change much; The production potential of wheat changed most obviously in the Northeast China Plain, and there’s a sharp decline after 1990. The Middle-lower Yangtse Plain and Huang-Huai-Hai Plain changed slightly noticeable, their tendency were all dropped slightly. The total productive potential of the corn and soybeans in the Northeast China Plain showed an increasing trend on the whole.(3) As far as the three climate factor variation in the nine agro-ecological zones, there was a tendency of increasing in the mean annual temperature, and the increase range was in 1 ℃; the amount of precipitation in southern China had a large fluctuation range, within 800mm. Followed by the Middle-lower Yangtse Plain, Yunnan-Guizhou Plateau and Sichuan Basin and surrounding regions, all of which were in 400mm. The amount of astronomical solar radiation in the nine agro-ecological zones had a similar variation tendency, they were all showed a downward trends before 1990, after that, it fluctuates smoothly in some ranges after 1990, and the fluctuation range were within 600 Mj/m2.(4) The correlation of national climatic factors with four kinds of total crop production potential in recent 50 years displayed obvious spatial differentiation. As a whole, precipitation is closely related to crops, then radiation, finally temperature. Rice in the four agro-ecological zones-north of Qinling Mountains-Huaihe River-was greatly influenced by radiation, radiation had a beneficial effects on the crops, Huang-Huai-Hai Plain had the greatest influence on radiation. Wheat was greatly influenced by precipitation, rainfall had a beneficial effects on the wheat in the north of Qinling Mountains-Huaihe River, Huang-Huai-Hai Plain benefited most, rainfall had a negative effects on the wheat in the south of Qinling Mountains-Huaihe River, Sichuan Basin and surrounding regions suffer most; Corn was greatly influenced by the climate. Precipitation had a positive influence on agricultural zones in the north of Qinling Mountains-Huaihe River line, while a negative influence on south, especially in Sichuan Basin and surrounding regions. Radiation had a relative unfavorable effects on the Northeast China Plain and the intersection between Northern arid and semiarid region and Loess Plateau, while a favorable effects on other sections in different degrees. Agro-ecological zones mostly in the Central and South coastal areas benefited most; soybean had relationship with precipitation and radiation, and soybean had similar spatial framework with corn, but to a different degree.(5) The mainly suitable area of rice are the Middle-lower Yangtse Plain and Huang-Huai-Hai Plain, the mainly suitable area of wheat, corn and soybean are all located in the Middle-lower Yangtse Plain, Huang-Huai-Hai Plain and the Northeast China Plain. In the main suitable planting area of rice, climatic change had a positive effects on the rice production. In the main suitable planting area of wheat, climatic change had a negative effects on the production of wheat; The production potential of com and soybeans in the Northeast China Plain received advantageous influence, the other two agro-ecological zones were adversely affected, besides, temperature was the main factor that imposed restrictions on these two crops. These conclusions can not only provide scientific basis for rational production layout but also give guidance to adjust the climate factors by manual to boost crop yields. |
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