1.2.1 Diversity

The Biggest difference between the natural forest and agriculture is the number of species. There is a large diversity of plant species in the natural forest - more than 100 species are found in one acre of land. In agricultural land, there are a few species or sometimes only one species (Mono-culture) per acre. Mono-culture in agricultural land is the main cause of the unbalanced agro-ecosystem.

1.2.2 Pest problems

There is almost no pest problem in the natural forest and it never occurs that one insect or one disease destroys the whole natural forest. Pest problems are very serious in agricultural land. One insect or one disease often destroys the entire crop. The main reason is mono-culture or lack of diversity. In the natural forest, so-called harmful insects and diseases cannot break out in isolation because there is a diversity of plant species and a balanced food chain (ecological pyramid), which puts the insects under certain conditions (numbers are limited). Even if an outbreak happens, the pest would never destroy the whole forest because it only attacks certain kinds of plants (diet habit).

1.2.3 Soil Fertility
The soil fertility maintenance system in the forest is ideal - gradually increasing and sustainable. There is no fertility depletion in the forest. The main reasons for this are the undisturbed nutrient cycle and vegetative cover on the soil. The nutrient cycle increases fertility in the soil and the vegetative cover protects and conserves it. On the other hand, fertility depletion is one of the main problems of agriculture. The nutrient cycle is always disturbed in agricultural land because most biomass prodution is taken out from the agricultural land through harvesting. Very little or almost no biomass is returned to the soil so the soil fertility in agricultural land is decreasing day by day. Furthermore, the bare soil causes soil erosion which makes soil fertility depletion worse.

1.2.4 Biomass Production

As the diagram shows, the forest can produce huge amount of biomass. The amount is more than two times that the agricultural land. The reason is the multi-story structure of the vegetation in the forest and again, the undisturbed nutrient cycle. Multiple stories ensure maximum utilization of natural energies (sun, rain, wind etc.) and the nutrient cycle supplies enough fertility to the soil. In agricultural land, the structure of vegetation is horizontal which cannot utilize the natural energies properly. The nutrient cycle is disturbed by taking products away from the land causing fertility depletion. Therefore production of agricultural land is less than that of the natural forest, despite many artificial (external) inputs. There are no artificial inputs needed in the natural forest.

Biomass Production in Different Ecosystems

(Soil Regeneration by S. Mori)