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| Spatial-temporal Variation of Agricultural Non-point Source Pollution Based on GIS Technology in Guangdong Province, China |
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| KeyWord:agricultural non-point source pollution; spatial-temporal variation; Guangdong Province |
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| Abstract: |
| 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 10.04×104 t, 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. |
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