Portuguese
vigna unguiculata Spanish
vigna unguiculata 
Sprawling Old World annual cultivated especially in southern United States for food and forage and green manure.
1
You will remember that only one-tenth of the total nitrogen of the cowpea plant remains in the roots and stubble?
2
Only about one-tenth of the nitrogen contained in the cowpea plant is left in the roots and stubble when the crop is harvested.
3
Often intercropped with maize and cotton, cowpea plants provide shade and dense cover that help protect soil and preserve moisture.
4
On the other hand, a stand of cowpea plants is surer in the case of soils that crust, and germination runs higher.