Industrial agriculture ignores this cycle. It's all about getting the most out of the environment, without any regard for what the environment actually needs to be the most productive. This is, obviously, completely counterproductive. Industrial agriculture is characterized by monoculture, pesticide-use, and GMOs.
Monoculture, the mass production of one plant species, both depletes biodiversity and encourages the invasion of pests. Certain pests are attracted to certain types of plants, and once they start feeding, they reproduce and spread like wild fire. In a whole field of one type of plant, pests have a field day, literally. And so, what is a quick fix for pests? Pesticides, of course. Supposed long term fix? GMOs, or Genetically Modified Organisms. Geneticists thought they were being smart by creating seeds that deter pests, but they've really messed things up. Watch this cheesy, but really comprehensive video called "The Story of Food" to understand (don't get turned off by the crazy beginning, it gets better):
Well, permaculture is a way to grow food that helps the environment thrive. It's about observing the environment and using its natural variation and tendencies to our advantage, by actually improving the environment. Through agriculture, we can truly be stewards of the environment.
An interesting practice used in permaculture design is companion planting. Different plants absorb and release different nutrients from and into the soil, affecting its composition. So, companion planting is all about growing the plantsthat "fix" the soil for each other close together, so they can encourage each other's growth. This method also deters pests, by making it harder for them to find the plant they're looking for. Plus, the other plants nearby may be poisonous to it. Want to try it? Here is a list of companion plants.