Bush beans stopped flowering

I received access to a 5000m2 (1,2 acres) field that had been ploughed and poorly harrowed by a tractor.  It all went pretty quick so I did not have as much time to prepare/plan as I would have liked to.

Amongst other things I planted bush beans , but they are really not doing well. They all just stopped flowering at a certain point and some of the pods also started turning yellow and falling off. I have attached pictures. Any ideas what the issue is?

From what I read it seems to me like it could be issues with the soil, maybe phosphorus and potassium missing. Or maybe a disease?

The beans have not received any soil amendments, but now I did started to add things like cow manure, wood ash to different parts of the beds to see if anything helps. But maybe it is already too late.

I also attached a picture of a pole bean, which seems like it leaves are starting to turn yellow, but it still is producing flowers and pods. Does that maybe have the same issues?

I also have planted runner beans and they are doing better but not great, they are flowering a lot, but only producing a small number of pods. I have also noticed some falling off.

Other crops have been doing better, I planted peas and potatoes without soil amendment and they have been doing fine. Summer squash, pumpkins and flint corn are doing pretty well, but they have also received some goat or cow manure.

The only other thing I know about the field is that the year before a farmer has been growing oats on that field.

There appears to be a bit of yellowing occuring.

Some things that can cause that include water stress (too much or too little), low soil fertility as you have a suspicion of, disease and pests.

As a first step, I would recommend a soil test to at least know where you are starting off from. There are home tests you can purchase that will give you an idea or you might consider sending a sample to a lab for an analysis.

How would you describe the soil? Sandy/Loamy/Clay?

The plants have yellowed a bit more in the past days since I have taken the picture. There has been some water stress, may and june where very wet and then at the end of july start of august we had a week without rain and quite warm, that is when I really started noticing the issues.

My initial guess on soil texture would be quite loamy and pretty good water holding capacity, but will take a sample when I get home to confirm.

Good idea with the lab analysis I will start researching that.