基于GIS的广东省农业面源污染的时空分异研究

Spatial-temporal Variation of Agricultural Non-point Source Pollution Based on GIS Technology in Guangdong Province,China

近年来,广东省化肥、农药等农用化学品的投入量大增,农业面源污染问题日趋严重。采用历年统计数据以及GIS技术,对广东省农业面源污染的时空分异性进行了分析。结果表明,全省化肥、农药使用量均呈逐年增加态势,化肥使用量由1990年的162.41万t增加到2010年的237.29万t,农药由1990年的7.95万t增加到2010年的10.44万t。畜禽粪尿排放量则由2000年的339.34亿t减少到2010年的222.08亿t;在空间分布上,全省化肥投入强度超过400 kg·hm-2的县(市)由1995年的35个增加到2010年的61个,粤西、粤东全部,珠三角大部以及粤北部分地区均属化肥严重污染区,其原因主要在于对农作物产量增加的追求。农药投入强度超过30 kg·hm-2的县(市)由1995年的10个增加到2010年的27个,这主要是由于广东的气候条件及种植结构改变造成的。畜禽粪尿排放污染情况相对较好,但因粤西的雷州半岛地区以水稻生产为主,大牲畜牛的养殖规模较大,因此畜禽粪尿重度污染主要集中在这一地区。GIS空间分析的运用,能直观地反映各地区农业面源污染的时空动态变化情况,为有针对性地开展污染治理提供依据。

Agriculture non-point source pollution (ANSP) is becoming a serious environmental concern in Guangdong Province due to the increased applications of agricultural chemicals such as fertilizers and pesticides in recent years. This study investigated the spatial-temporal variation of ANSP using the historical statistical data and GIS technology. Results showed that the fertilizer, pesticide and other agrochemical applications in Guangdong Province were increased and reached quite a high level in order to secure food supply. The total amount of chemical fertilizer application increased from 1.62×106 t in 1990 to 2.73×106 t in 2010 and the total amount of pesticide application elevated from 7.95×104 t to 10.04×10 4t, while the total amount of animal manure application decreased from 3.39×1010 t in 2000 to 2.22×1010 t in 2010. The spatial distribution analysis showed that the number of counties with a fertilizer application rate>400 kg·hm-2 was 35 in 1995 and reached 61 in 2010. The western and eastern parts of Guangdong as a whole as well as the northern part of Guangdong and the major part of the Pearl River Delta were identified as the heavily polluted areas as a result of increasing applications of fertilizers and other agricultural chemicals due to the pressure for increasing crop yields. Meanwhile, the number of counties/cities with the pesticide application rate >30 kg·hm-2 was 10 in 1995 and reached 27 in 2010, which were the results of the more pesticide production under the tropical and subtropical climate and the change of crop structure. In contrast, the animal manure pollutants discharged from the livestock farms were relatively low. The heavily manure polluted areas were mainly concentrated in Leizhou Peninsula in the southwestern part of Guangdong Province, which was the production of large number of cattle raised for rice field operation. Through GIS mapping, the spatial-temporal distribution of ANSP in the study area was demonstrated. And the GIS And the GIS technology would provide a clear visual pattern for further development of pollution control measures.