The organic horizon is generally absent from agricultural soils because tilling, e.g., plowing, buries organic matter. Why is an organic horizon generally absent in desert soils?

Explanation

(i) O-Horizon (Organic horizon) Consists of fresh or partially decomposed organic matter.
(ii) `O_(1)` - Freshly fallen leaves, twigs, flowers and fruits `O_(2)` - Dead plants, animals and their excreta decomposed by micro-organisms.
(iii) Desert soil has very little water to support a large community of plants and animals.
(iv) Therefore the formation of O-Horizon is very negligible or absent in dessert soil.