Assessment of Interactions between Agricultural Water Usage and Water Quality in California under Environment Change

Abstract:

Agriculture is a critical part of California’s development; However, droughts pose a huge threat to agricultural water resources. It has been suggested that climate change is the main factor that leads to severe water scarcity in California. Previous research has also shown that pesticides and fertilizer usage influence California’s water quality. However, little research studies the effect of agricultural practices on water quality under the climate changing. This paper presents a novel view of the relationship between agricultural water usage and water quality, and the originality of this study lies in the fact that there is not a clear investigation about the interactions between agriculture practices and water quality under climate change. This quantitative research aims to build a possible relationship between agricultural water usage and water quality, and the water quality data, water usage data, and California’s local climate data used in this research were obtained from the United States Geological Survey. This research divides California into eight regions, and regression and correlation statistical analysis was made to address the statistical relationship between agricultural water usage and water quality in each region, results comparisons are also made between each region to investigate the regional difference. ANOVA and Tukey HSD test were conducted to investigate whether there is a strong chance that water quality change is casually related to regions. This paper suggests that a positive relationship lies between agriculture usage and dissolved oxygen and nitrate, an indicator of water quality. Increasing agriculture usage leads to an increase in dissolved oxygen, and dissolved nitrate in the water. Region level research in this paper shows that the dissolved oxygen in water decreases with higher temperature, the water dissolved oxygen in agriculture developed region is slightly higher than that in less developed region. These results indicate that developed agriculture positively related dissolved oxygen in the water, and water temperature is negatively related to dissolved oxygen. Thus, under the condition of climate change, drought and extreme temperatures cause higher water temperature, which leads to lower water dissolved oxygen that undermines agriculture practices.