Steep slopes are not ideal, nor is land with stagnant standing water. In contrast, limestone bedrock forces water to travel laterally across its surface, and the result is often natural springs offering mineral-rich water. Whatever the soil type, it is important that it not be too high in clay content. Clay soils can be very slippery for horse hoofs when wet. The amount of acreage needed to keep each horse fed depends on climate, vegetation, and time of year, but the average is around two acres per horse.
Good grass is good for horses.
Even so, some horses need other feed supplements in order to maintain optimum health. In the winter, pasture production typically falls well short of what horses need, and fine quality hay is offered instead. It is often easier to add vitamin and mineral supplements to a horse's feed than to add fertilizers to the soil. Horses that are in intense training benefit from feed concentrates, as young horses and lactating mares also do. Nutrition programs for working horses are best designed by a veterinarian, to take the guesswork out of feeding.