Salem

White corn: says in wiki - 100 to 150 Total, but with more Red than blue.
These are my field stats and im getting loads of gold and blue corn - what am i doing wrong?

Both bars give out golden corn.
For a specific 2nd tier I use just of the bars. And If you have both I believe one should be below 50. In your case the sum of the two bars is 169 and that is way over 150.

From the Wiki:
http://salemwiki.info/index.php/Agriculture/Crop_Growth_and_Rotation#Crop_Tiers

If the sum is below 150, then the tier 2 product is in the same order on the two tables. For example, a field with the first bar at 100 and the second at 0 could produce Indian Cotton, while a field with the first bar at 0 and the second at 100 could produce Egyptian Cotton. If the sum is above 150, then the lower of the two influence bars determines the type of tier 2 product. For example, a field with the first bar at 95 and the second bar at 80 could produce a mixture of Sea Island Cotton and Egyptian Cotton.

In your case:

If the sum is below 150, then the tier 2 product is in the same order on the two tables. For example, a field with the first bar at 100 and the third bar at 0 could produce White Corn, while a field with the first bar at 0 and the third bar at 100 could produce Blue Corn. If the sum is above 150, then the lower of the two influence bars determines the type of tier 2 product. For example, a field with the first bar at 89 and the third bar at 80 could produce a mixture of Golden Corn and Blue Corn.

The good news is that after each harvest the other bars drop by 5, so your new total would be 159. One more harvest, you'll be down to 149 and then you'll switch over to the other T2 product.

I used to not like this idea, that the LOWER of the two bars determines the T2 crop when T3 is present. But I realized that it allows harvesting of all 3 types of crops from a single field as the other influences lower. Best variety for least effort, overall it's a benefit and I haven't had trouble remembering this since realizing it.