It mostly doesn’t, at least not on its own. This is why fertilizer is such a big sell for people who like lush green lawns. The lawn will use up the growth-limiting nutrients like ammonia, nitrate, phosphorous, perhaps potassium, fairly quickly (over a few years, usually) and the grass will start to struggle (thin out) and get invaded by “weed” plants that have different nutrient needs (can thrive where the grass struggles).
Basically, the weed invasion is part of the effort of nature to get the ground into a more balanced condition, where plant activity complements itself, some making nitrates that others need, and getting maybe phosphorous,potassium, or something useful, in return. Some of the elements can be obtained from the soil (the rock bits that make up the soil have many elements that can be extracted by some plants).
This nutrient problem is one reason that mulching when cutting grass is favored by many people over removing the clippings. Recycling is better than removing and making you get more to replace it from somewhere else.
The ground starts with a fixed amount of everything, more or less. If you remove some, then the ground has to supply more to the plants, and eventually, the ground starts to run out. However, some plants do take nitrogen from the air and put it in the ground (self-fertilize, in a away). I don’t think grasses are very good at that.
A healthy, self-sustaining vegetation really benefits from the return of dead matter back into the soil, where bacterial breakdown releases nutrients back to the plants to keep them growing. Taking that stuff away is slow starvation, basically.
Plants are made mostly of Carbon, and while it will suck water and some trace nutrients from the ground, the vast majority of the plant is from Carbon.
Where does the Carbon come from? from the CO2, Carbon Dioxide, in the air. So the vast majority of the plants mass never came from the yard, but from the air.
Look at a tree, think about how much it weighs. That is roughly the amount of CO2 it needed to convert out of the atmosphere to grow that large.
Plants are made mostly of Carbon, and while it will suck water and some trace nutrients from the ground, the vast majority of the plant is from Carbon.
Where does the Carbon come from? from the CO2, Carbon Dioxide, in the air. So the vast majority of the plants mass never came from the yard, but from the air.
Look at a tree, think about how much it weighs. That is roughly the amount of CO2 it needed to convert out of the atmosphere to grow that large.
Plants turn air, water, and soil into more plant, just like animals turn air, water, and food into more animal. All living things grow by incorporating matter from their environment.
You may be missing all the matter that comes from the air, which is somewhat less intuitive and easy to ignore. It’s the same reason why it’s a little surprising that burning 1kg of coal produces over 2kg of carbon dioxide – lots of matter in the air.
Plants turn air, water, and soil into more plant, just like animals turn air, water, and food into more animal. All living things grow by incorporating matter from their environment.
You may be missing all the matter that comes from the air, which is somewhat less intuitive and easy to ignore. It’s the same reason why it’s a little surprising that burning 1kg of coal produces over 2kg of carbon dioxide – lots of matter in the air.
Plants turn air, water, and soil into more plant, just like animals turn air, water, and food into more animal. All living things grow by incorporating matter from their environment.
You may be missing all the matter that comes from the air, which is somewhat less intuitive and easy to ignore. It’s the same reason why it’s a little surprising that burning 1kg of coal produces over 2kg of carbon dioxide – lots of matter in the air.
Latest Answers