Python, ask 3D scatter plot to set up annotation

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d import Axes3D

%matplotlib notebook

fig = plt.figure(figsize = (10,10))
ax = fig.add_subplot(111, projection='3d')

ax.scatter(np.log10(yie[pot.index]), np.log10(price[pot.index]), np.log10(pot), 
s = 150,c = 'g' , label = 'Potassium')
ax.scatter(np.log10(yie[fib.index]), np.log10(price[fib.index]), np.log10(fib), 
s = 150, c = 'b', label = 'Fiber')
ax.scatter(np.log10(yie[iro.index]), np.log10(price[iro.index]), np.log10(iro), 
s = 150, c= 'r', label = 'Iron')
ax.scatter(np.log10(yie[cal.index]), np.log10(price[cal.index]), np.log10(cal), 
s = 150, c = 'y', label = 'Calcium')

ax.legend()
ax.set_xlabel('Yield')
ax.set_ylabel('Price per lb')
ax.set_zlabel('Nutritions')
plt.show()