I've had a few questions about our arena and "pasture" (California style).
We use washed concrete sand in our arena. I think sand types vary around the country, and internationally, but washed concrete sand is the type of sand most commonly used for arenas in California. There is a base of decomposed granite - again the crushed rock source probably varies from place to place. Granite is everywhere here. So, there is the base, then the sand, and then a product called AirFoot that is mixed into the sand. AirFoot is a mix of fiber and rubber. It looks like chopped up running shoes and has been nicknamed "Nike footing." The AirFoot aids with water retention, reduces dust, and creates fluffiness. We installed it four years ago and it should last ten years. The initial investment was high but I haven't regretted it at all. The arena is used for schooling. We don't use it for turnout except in cases where the horses cannot go out into the pasture.
Here in Southern California, grass pastures are very very rare. If you are driving along a road in a horse community and see one, you slam on your brakes and stare.
Reason #1: Real estate prices are ridiculous. Horses require at least an acre each for grass pasture. There is an empty lot near us, 2.5 acres (1 hectacre), and it is for sale. $100,000. Seriously, who can afford to put two horses on that? Not me. Not most Californians.
Reason #2: Our climate does not encourage grass growth. We get no rain at all between the beginning of May and the end of November. It is freezing and most plants are dormant from November until April. Native grass grows in March and April. Our hills are already brown. We do irrigate a small section of grass but the amount of water it requires is high. We pay a premium for water (which is premium by definition in Southern California) because it has to be piped up the mountain. There are a few wells up here but they don't produce enough water to support our small community.
Most of the front yard is planted in drought resistant perennials such as lavendar, sage, yarrow, blanket flower, agastache and Jupiter's beard.
The slope between the house and arena is planted with a wonderful hedge of a California native called Coyote Bush. It is a wonderful shade of green (most native/drought resistant plants are an olive green or grey green) and grows into a dense groundcover. I try not to think of the snakes that probably live in it.
Reason #3: The soil is very poor. The mountains in which we live are comprised of granite, shale and a bit of clay thrown in here and there. Although we live in a wilderness area, surrounded by the National forest, it is a forest comprised of scrub oak, mesquite, manzanita, yucca and sage. It is fragrant and beautiful in its own way, but it is not lush by any standards. I compost the horses' manure and we spread it everywhere. The only part of the property that does not require additional water to grow is my agave/aloe garden. The new goat area gives a good example of what grows on the unimproved soil.
Keep the questions coming! I'm off to ride Jackson on the new sand in the arena.