In this graph, we compared our sites’ soil pH with their longitude (east-west location).  We found that sites further east out on the plains tend to have higher pH than sites closer to the Front Range foothills and up in the mountains.  This could be due to several things. 
Precipitation is higher in the mountains and foothills than further out on the plains.  Higher rainfall is associated with more acidic soil.  Also, a site’s original parent soil material is more acidic in the mountains and foothills than on the plains.  Furthermore, the pH of irrigation water can change soil pH with repeated applications.  Irrigation water becomes more alkaline as it travels further east away from the mountains, picking up tailwater, salts and minerals.  All this means that the location of a field might determine its soil pH as well as its soil health, since soil pH has a significant effect on soil health. (As pH increases and becomes more alkaline, soil health decreases.)

We calculated each of our 7 crop group’s average longitude and average pH, which is shown in the following two graphs.  No surprise, trees are located to the west in our forests, with dryland gains and commodity crops located to the east, where large sections of undeveloped agricultural lands remain.  In the second graph, you can see how the order of the average pH of the 7 groups closely corresponds to their relative longitude, as shown in the first graph.  Groups further east had the highest pH, while groups further west had the lowest pH.  These 2 graphs suggest that some crop groups face more of a disadvantage than others when it comes to soil health, since their location can determine their soil pH, which in turn can make improving their soil’s health more difficult.