Questions about 13 data from Valley

Dear Maja,

There are some questions about the data： 1. Can potato, onion-potato-corn and various vegetables land be regarded as the same land use? 2. Sample 6, which has low pH (4.2) and a medium content of OM, results in the highest CEC. The soil of Delta does not contain much clay. I really don't know why. 3. Data 12, the Exch. Na is 31.8 that much larger than other groups. The Exch Mg+ Ca> CEC. Are there any mistakes?

Bill

A.1. For this simplistic comparison, yes all those agricultural crops (vegetables, potatoes) can be grouped together since they have similar management practices.
A.2. Pls check (in the background info package) what are the typical properties for each soil series included in the data set (remember names Delta, Lumbum, Crescent, etc. are the names of soil series). Also, keep in mind that chemical fertilizers (specially N-fertilizers) have an acidifying effect in soil.
A.3. No, this is not a typo, soil #12 does indeed have such a high sodium content. Look at the background info for that soil, the answer is there .... and no, I am not telling what it is ;-)