Soil nutrient depletion is a factor of commercial growing of vegetables.  Even with fertilizers, soil grows tired.  Demand dictates that ground can no longer lay fallow (unused) for a year as was the custom decades and centuries ago.  This practice would allow the ground to rejuvenate replacing the nutrients back into the soil. 

HHG practices vertical aeroponic farming.  This technique  allows us to grow vegetables in an organic nutrient rich solution while being exposed to the air.  The roots being exposed to the air offers super oxygenation allowing the plants to take on 40% more nutrients that those grown in soil.  All this while using 95% less water than soil grown crops.