Which of the following does the USDA NOT attribute as a general source of reduced water quality? Manure runoff Soil erosion Over-application of fertilizer Excess groundwater

## Step 1<br />The USDA (United States Department of Agriculture) has identified several factors that can lead to reduced water quality. These factors include manure runoff, soil erosion, and over-application of fertilizer. <br /><br />## Step 2<br />Manure runoff refers to the situation where animal waste is washed away into water bodies, leading to contamination. <br /><br />## Step 3<br />Soil erosion is a process where the top layer of soil is washed or blown away, which can lead to sedimentation in water bodies, reducing water quality. <br /><br />## Step 4<br />Over-application of fertilizer can lead to nutrient runoff, which can cause eutrophication in water bodies, again reducing water quality. <br /><br />## Step 5<br />However, excess groundwater is not a direct source of reduced water quality. Groundwater is water found underground in the cracks and spaces in soil, sand, and rock. It is stored in and moves slowly through geologic formations of soil, sand, and rocks called aquifers. The term "excess groundwater" is not a recognized term in the context of water quality issues.