he resulting nutritional quality of the food we grow.

Imagine trying to make compost from deficient materials such as a heap of pure, moist sawdust. What happens? Very little and very, very slowly. Trees locate most of their nutrient accumulation in their leaves to make protein for photosynthesis. A small amount goes into making bark. Wood itself is virtually pure cellulose, derived from air and water. If, when we farmed trees, we removed only the wood and left the leaves and bark on the site, we would be removing next to nothing from the soil. If the sawdust comes from a lumber mill, as opposed to a cabinet shop, it may also contain some bark and consequently small amounts of other essential nutrients.

Thoroughly moistened and heaped up, a sawdust pile would not heat up, only a few primary decomposers would take up residence. A person could wait five years for compost to form from pure moist sawdust and still not much would happen. Perhaps that's why the words "compost" and "compot" as the British mean it, are connected. In England, a compot is a slightly fermented mixture of many things like fruits. If we mixed the sawdust with other materials having a very low C/N, then it would decompose, along with the other items.

CHAPTER THREE

Practical Compost Making

To make compost rot rapidly you need to achieve a strong and lasting rise in temperature. Cold piles will eventually decompose and humus will eventually form but, without heat, the process can take a long, long time. Getting a pile to heat up promptly and stay hot requires the right mixture of materials and a sensible handling of the pile's air and moisture supply.

Compost piles come with some built-in obstacles. The intense heat and biological activity make a heap slump into an airless mass, yet if composting is to continue the pile must