While drip irrigation has a number of benefits, it tends to be a somewhat expensive system to set up. Estimates are that drip irrigation can cost anywhere from $500 all the way up $1,000 per acre. Furthermore, there are many areas for which this type of irrigation system is just not well-suited.
One way to make drip irrigation a bit more cost-effective is by putting in irrigation tubing below the surface. In general, sub-surface irrigation works best when the tubing is placed about five inches (12.7 centimeters) underneath the surface. By providing a more direct route for water to reach the roots of plants, evaporation decreases significantly. Plastic mulch can have the same effect and is much less expensive to use. Mulch is basically an organic material that is placed around plants in order to prevent weeds from growing, to protect roots from damage caused by frost and to reduce evaporation. While plastic mulch is being used increasingly by horticulturalists to enhance their plants' growth and quality, others have raised concerns about the potential environmental impact of this type of mulch. Some have predicted that in the long-term, plastic mulch could cause more pesticides to wind up in nearby water supplies.
While drip irrigation has proven to be a successful innovation in the field of horticulture, this method isn't without its weak points (aside from the cost). For example, unfiltered water can clog a finely tuned drip irrigation system very quickly. Nonetheless, the negative environmental impact of surface irrigation techniques - versus drip irrigation techniques -- including soil erosion and water evaporation, make drip irrigation an advantageous, viable and relatively eco-friendly alternative.