| Summary: | 碩士 === 國立中興大學 === 土壤環境科學系所 === 99 === In the course of agricultural production, it is necessary to use the fertilizer in order to obtain better income from farming cultivation. If farmers directly use the manure in their farmland, not only can they reduce the amount of application of chemical fertilizers, but also can avoid losses of nitrogen and negative impact on the environment. This also can solve the problem of the waste water from animal husbandry being too salty to enter the irrigation canal.
To investigate the chemical characteristics of groundwater in fields applied manure, this study employed hygrochemical phase to explain the space distribution relation of groundwater. We also applied principal components analysis (PCA) to explain the hydrochemical structure of the groundwater. The goal of this study was to understand the impact of directly using manure as fertilizer on groundwater water quality. In view of this, we monitored 16 groundwater wells in FangYuan, ChangHua.
The results of analysis indicate that the groundwater in the study field had a pH about 7. In general, the EC value of the groundwater is higher than that of water standards. By comparison, the DO value of the groundwater is lower than that of the standards, indicating anaerobic environment for the groundwater.
The hydrochemical facies showed that Ca2+-Mg2+-SO42--HCO3- is the main water type for the groundwater. The facies for the groundwater in the up- and down-stream region is (Ca , Mg) - HCO3, and that in mid-stream groundwater is (Ca , Mg) - SO4. The hydrochemical facies of the groundwater indicates that dissolutions of carbonate and sulphate are the fundamental processes affecting the chemical characteristics of the studied groundwater. The PCA sorted out three major components affecting the groundwater quality: fertilizer pollution, alkalinity and animal husbandry pollution.
These results point out that applied manure as fertilizer would pollute groundwater, however, the pollution levels do not surpass water standards. Nonetheless, both seepage of manure storage and nitrate pollution in groundwater still need to be careful.
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