These things reduce the input human labour required to produce some good. They are inputs to the process of production, but do not themselves produce value. In

These things reduce the input human labour required to produce some good. They are inputs to the process of production, but do not themselves produce value. In fact, as I mentioned, they may well diminish the value of some product, because they reduce the abstract human labour required to produce it. Your second question isn’t really helpful ... the simple answer is sustained famine in the 90s, poorly maintained land, and market forces.