This solution is designed for ...

This solution is designed for a long time by various companies. I remember talking about this with a manager of BASF. They are testing a product that you put in the soil and absorbs water. One gram is capable of holding 400 grams of water.
It is the same system for the nappy of children. The problem is its durability and other salts which brings to the ground. I think we can use in desert areas and where there is little rain. I use subsurface drip irrigation for 17 years and I think in some areas and on some crops this product is ideal.