Impacts Of Climatic Changes On Crop Potential Productivity In Northeast China

Under the background of global climatic warming, climate has more and moreevident impacts on agriculture and crop potential productivity. Northeast China, a highlatitude region including three provinces of Heilongjiang, Jilin and Liaoning, issensitive to climatic changes. In order to study the impacts of climatic changes onagriculture, we selected Northeast China as an example, and 72 meteorological stationsin Northeast China were covered, the climatic factors including light, temperature,precipitation as well as data about the growing periods and yields of the main crops inNortheast China were collected. Based on Geographic Information System (GIS), weanalyzed the spatial-temporal patterns of radiation, temperature and precipitation from1961 to 2004 in Northeast China. Based on Mechanism Method, we graduallycorrected crop potential productivity models on the parameters of light, heat andmoisture, and calculated the photosynthetic potential, light-heat potential, and climaticpotential of main crops, e.g. maize, rice and soybean in Northeast China.The main research results were summarized as follows: (1) The temporal patternsof radiation showed a decreasing trend from 1961 to 2004, and the spatial patterns ofannual total radiation and the radiation during growing periods showed an increasingtrend from east to west. The dynamic change of the spatial-temporal patterns of dailysunshine hours was similar to that of radiation. (2) Annual steady duration of≥10℃,annual active accumulated temperature and monthly mean temperature in growingperiods appeared in an increasing trend during the 44 years, and their spatial patternsappeared in a decreasing trend from southwest to northeast. (3) Both annual andgrowing periods precipitation showed a decreasing trends along time series, the spatialpattern of annual precipitation appeared in a decreasing trend from south to north, withthe maximum occurring in the eastern part of Liaoning Province; The western parts ofevery province were in defect of precipitation, and there existed a marked: regionalvariance in precipitation within every province; during the 44 years the index ofprecipitation concentration was distinctly decreasing. (4)Because the radiationdecreased, the photosynthetic potential productivity reduced. However, the light-heatpotential productivity and climatic potential productivity appeared in a increasing trendto a different extent owing to an increased temperature. The photosynthetic potentialshad not much difference in various areas, and the light-heat potential productivityappeared in a decreasing trend from west to east, and climatic potential productivity in a decreasing trend from south to north. (5) The maximal values of climaticproductivity increment potential of maize were mainly located in Liaoning Province,the maximal values of climatic productivity increment potential of rice were in thewestern part of Northeast China and the areas around Mudanjiang and Yanji, and themaximal values of climatic productivity incrcment potential of soybean in most ofLiaoning Province and Yanji of Jilin Province. There were significant differences inutilization efficiency of agro-natural resources in main crops in different counties ofNortheast China. The areas with a greater yield-increasing potential had a lowerutilization efficiency of resources.