| Under the background of global warming, climate change will lead to temporal and spatial variations in the quantity and quality of agricultural climate resources that were related to agriculture production, and increase the instability of agriculture production. Thereby, in the condition of the greater climate variability, it has an important significance to evaluate objectively the effects of global warming to agriculture production in Jianghuai region and the trend and utilization of climate resources, and analyze the effects of this change to agri-climatic potential productivity, for establishing a reasonable agricultural cropping system, putting forward practical adaptive measures to keep agricultural production in the Jianghuai region caused by climate change, excavating and simulation of rice and wheat in this region under the future climate, and achieving the produce increase of rice and wheat.Daily temperature, light and precipitation data ranged from 1960 to 2007, collected by 32 meteorological stations in the Jianghuai region (Jiangsu province and the region in the north of Yangtze River in the Anhui province), and historical production of rice-wheat and growth and development data collected by 22 crop phonology observation stations are available in this paper. The statistics analysis and GIS interpolation analysis methods were introduced in this paper. In this study, authors analyzed the temporal and spatial evolution characteristics of agricultural climate resources, such as, temperature in the growing season, solar radiation and precipitation in the Jianghuai region, furthermore, understood the temporal and spatial evolution law of wheat-rice production potential at all levels during 1960 to 2007. The estimated value between climate potential productivity and actual wheat-rice yield were used to analyze the yield potential in the different regions by GIS overlay analysis. Through analyzing the years of production data in the Jianghuai region and characteristic data about growth and development collected by 22 stations, it explored the problems of wheat-rice climate self-adaptability, and on this basis, made wheat-rice cultivation strategy to adapt the climate change. There are main conclusions showing as below:1. In the Jianghuai region, the mean temperature of year, winter wheat and rice growing season showed a significant upward trend by 0.28℃,0.39℃and 0.17℃per decade since 1960s, respectively. It reported that the temperature rise mainly was in winter and spring, both maximum temperature and minimum temperature has a upward trend, and the minimum temperature has a greater rate of increase which indicated that night temperature shows a stronger upward trend than daytime temperature, Accumulated temperature above 10℃increases obviously with an upward trend of 79℃,57℃and 31℃per decade, respectively. The temperature increment was clearer in winter and spring than that in summer. The spatial distributions of mean temperature, maximum temperature, minimum temperature and accumulated temperature present a down trend from south to north all the year. In 2000s, compared with 1960s, the temperature increases most strongly in the northern region with isotherm moving towards north about 50-150 km。2. The growing season total precipitation presents a vibration trend with slight uptrend from 1960 to 2007. The days of precipitation and precipitation intensity didn't change significantly neither in the wheat growing season nor all the year round, while days of precipitation showed a downward trend with time and precipitation intensity has a strongly uptrend in the rice growing season. There was little change in the spatial distribution of annual precipitation and days of precipitation were more in the south than those in the north in recent decades. The spatial distribution of precipitation and days of precipitation in the wheat growing season were same to those all the year, however, the southern precipitation and precipitation day increased, while there is little change in the north. There was a large spatial variability of rice in the growing season, the precipitation days decreasing from south to north, and the numbers of precipitation days reducing significantly in 2000s in the whole region. 3. During the whole year, growing seasons of wheat and rice in Jianghuai region from 1960 to 2007, average annual hours of sunshine showed a significant downward trend of 8.1 h,12.1 h and 3.1 h per decade, respectively, and the total solar radiation showed a strongly downward trend with 12.3,4.4 and 9.1 MJ m-2 per decade, respectively. In summer, sunshine duration and solar radiation had a larger reduce than in winter. The spatial distribution of hours of sunshine and solar radiation descend from south to north.The reduction was most significant in 2000s; followed by reduction in the south, while little change in the northern region. 4. In Jianghuai Region since 1960, the potential photosynthetic production had a down trend, while the production potential of light and temperature and the climatic potential productivity showed an upward trend. The changes of these were -1 742 kg hm-2,678 kg hm-2, and 829 kg hm-2 compared 2000s and 1960s. On the other hand, in the rice production, three indicates simultaneously showed a downward trend. The changes of these were 3 846 kg hm-2,3 310 kg hm-2 and 3310 kg hm"2 compared 2000s and 1960s. The spatial distribution of the potential photosynthetic production of rice gradually reduced from north to south, and the spatial distribution of the production potential of light and temperature and the climatic potential productivity descended from south to north. The spatial distribution of the potential photosynthetic production of winter wheat gradually reduced from south to north in the Jianghuai Region, while the climatic potential productivity reduced on the opposite direction, in spite of significant increments since 1960 in the southeast of the region. The production potential of light and temperature was greater in the southeast and southwest due to a higher temperature.5. The maximum per unit region yield of wheat in actual production was 5 400 kg hm-2 in the middle of Jiangsu province and the northern region of Anhui province, while the minimum yield was under 2500 kg hm-2 in the southwest of Anhui province. The production of rice reduced gradually from east to west. The maximum per unit region yield was 8800 kg hm-2 in the east of Jiangsu province. on the contrary, the minimum is 6000 kg hm"2 in the southwest of Anhui province. The yield-increasing potential of light-temperature of wheat showing a downtrend from south to northwest, which ranged between 5 000 kg hm-2 and 7 500 kg hm-2, was greater than the yield-increasing potential of light-temperature of rice descending from south to north, which ranged between 11 500 kg hm-2 and 13 000 kg hm-2.6. Because of the self-adaptability characteristics, the historical yield showed a continuous uptrend instead of the decline caused by global warming. For wheat, the length of growing period has been shorten with seeding time put-off and early maturity, while rice has little variation. The wheat has moved north with the crop boundaries moving northwards more than 50 km in Jiangsu province.In theory, since this century, triple-cropping system could be carried out in the middle and much of southern of Jiangsu province and more than two of three in Anhui province.The boundary of triple-cropping system maybe moved northwards 100 to 200 km.7. Based on the characteristic of global warming in Jianghuai region, authors suggests several measures, such as, modifying the crop boundaries and pattern and sowing time appropriately, introducing a good variety scientifically, selecting crop varieties correctly, constructing farm irrigation facilities, applying inorganic fertilizers combined with organic ones and enhancing soil organic matters and improving the soil environment to mitigate the impact of these climatic factors on wheat and rice in the representative regions. |
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