Composting is a natural recycling process performed by micro-organisms that exist naturally in the soil. Regular addition of compost to soil will provide benefits for the growth of plants. Compost also reduces soil erosion by holding water so it can percolate into lower soil layers rather than run off. Compost also reduces crusting of the soil surface by slowing evaporation. Compost provides nutrition for earthworms, soil insects, and micro-organisms, many of which will help balance the populations of less desirable soil fauna over time. The products of the composting process contain common elements (e.g. nitrogen, phosphorous, potassium, magnesium) found in synthetic fertilizers, as well as many trace elements not available from commonly used synthetic fertilizers.