粮食产量的自然与人为影响因素定量分析—以济南市为例

The Quantitative Analysis of Natural and Man-made Factors Influencing Grain Yield Variation in Ji'nan City

选取济南市1978-2008年共31年的粮食产量及同时期的20个自然与社会经济因子,利用主成分分析对自然与人为要素作用强度进行了量化分析。结果表明,在济南市粮食产量变化过程中,人为因素的贡献率为58.18%,自然因素的贡献率为32.23%,自然与人为因素共同作用的贡献率为6.47%。对济南市粮食产量影响最大的自然因素主要有年均气温、积温、年降水量、年日照时数;人为因素主要有耕地面积、农用机械总动力、化肥施用总量、每公顷耕地化肥施用量、农村劳动力数量、总人口数量。自然因素的贡献率随时间推移逐渐降低,人为因素的贡献率逐渐升高。结合相关因子的历年变化情况分析表明,在自然因素较为稳定的情况下,人为因素愈加重要,并直接决定粮食的单位面积产量和总产量,即农业技术进步对提高粮食作物单产起了决定性作用。

In order to study the intensity of natural and human activity in grain production process, the grain yield of Ji＇nan city was analyzed from 1978 to 2008. Twenty factors were chosen and the principal component analysis method was used to measure the intensity of nature and human activity factors. The results showed that in the change process of grain production, 58.18% was caused by anthropogenic activity, 32.23% was caused by nature factors, and 6.47% was caused by anthropogenic activity combined with nature factors in Ji＇nan city. The main nature factors were annual mean temperature, cumulative？ temperature, annual precipitation and annual sunshine duration. The main anthropogenic factors included cultivated area, total power of agricultural machinery, fertilizer, rural labor force and total population. The contribution of nature factors decreased gradually, while the contribution of anthropogenic factors increased from 1978 to 2008.