So many farmers, including me years ago because that was the way I was raised and taught was that we used soybeans and also wheat as scavenger crops using them to scavage fertilizer from our main cash crops Cotton in our case and corn in the corn belt, we found that irrigation was best investment in the 80's and now some our neighbors are applying 100 plus units of phosphorous and 50 to 60 units of potassium behind corn to there bean fields behind corn

yes they will,

Ive always wondered since soybeans are a legume and make their own nitrogen, will they still take nitrogen thats already in the soil?

What was the WEED!!!!