I have read a couple posts from members discussing the quantity of manure they have applied. I seem to recall amounts like 6-8 inches thick. What I am understanding by that is- actually put down a layer 6-8 inches thick, then till it in. Then plant into that. I am worried about putting too much.
Manure contains a lot of salt from the urine and can build up in your soil to damage your garden. How much you can apply depends on your climate and how much moisture the manure was exposed to while it aged. Primarily, the salts will wash out with sufficient water. I would guess that you are in a more limited rainfall area and probably apply some supplemental irrigation to the garden. If you apply too much manure, it could salt the ground out. Beans are pretty sensitive to salt and will be some of the first plants to fail to perform or even die if salt levels are too high.
I used to add 2 to 4 inches of manure a year to the garden, then we went through several years of drought and started irrigating with a sprinkler instead of flood irrigation--i.e. I stopped washing the salts out of the soil by limiting water application. It didn't take too long to figure out that the salts were building up to the point that I was getting a lot of problems with everything that was salt sensitive. In addition, I started getting some mineral deficiencies.
After a soil test from Ward Labs (located in Kansas), I found that the micro nutrients were way high, and the overload of some micronutrients was causing problems for the plants to take up other micro nutrients, even though those were also in excess supply. They even wrote on the soil test results to stop applying so much manure, even though I hadn't told them that I did apply manure. Fortunately, the drought lifted for a while and I was able to flood irrigate again to move the excess salts out of the upper soil profile. I also stopped applying manure for a couple years to let the nutrient levels fall.
Since then, I add less manure and instead add organic matter during the summer (residue composed mostly of alfalfa leaves) which can then decompose in the soil for the next year. My salt and micro nutrient issues have disappeared, I'm still maintaining organic matter content in the soil of 2-4% (natural levels here are <1%) and the garden is happy.
Adding nitrogen is still needed to give the plants a boost. I also noticed that when I reduced the manure, my disease issues with the potatoes, tomatoes, and peppers declined. I think the manure was providing a host for soil born diseases. It was just a case of "if a little is good, more isn't better".