The litter layer 9sometimes called the Soil Horizon) is the most important layer. This is the place where the soil and outer world meet. It is also the place where plant nutrients from old plants enter back into the soil system. It is also the gateway for water and air to enter and escape. By controlling the kind of latter layer applied, you can control the amount of air, micro biology and water moving through it.
When thinking about soil and the microbiology as an ecosystem, there are three places where the world micro biology needs to be the most plentiful. It is the soil layer, the litter layer and the canopy layer. Many of the micro organisms in the soil are also contained on the stems and leaves of plants. It is important for micro biology to be present on leaves. Leaves are made up of cells. Each cell has portal layers on the outer cell membrane. These portals have keys where certain type of bacteria and/or fungi can connect with it. The connection between the leave cell and the fungi/bacteria is symbiotic for the most part. There are other bacteria and fungi that are pathogenic. These are the creators that give trouble to plants in the form of diseases.
To prevent diseases on plants, the micro eco system needs to have at least 70% of the leaves covered with micro organisms. In general the urban garden has around 10% covered. Micro organisms move to the leaves through microarthorpds. Some examples would be flies and aphids. The home gardener can also help compromised gardens by spraying compost teas.
The general rule of them when growing soil is to mulch all of the dead plant material and use it as the mulch or litter layer. Do not take away the dead plant material to a compost pile, compost it and then return it back to the litter layer. That will change the type of micro biology for that soil area. Only use the litter layer of the soil from that area.
The general thought is the micro biology of the soil will follow the types of litter layers and canopies. If the canopy of a soil are veggies, make sure to mulch the veggies and replace it on top of that soil. That will keep the soil bacteria dominated. If you have a confer area, take the needles and mulch them. Put them back on the same spot. That will help the confers grow more than placing composted veggies.
Last, there is a way to make a compost litter layer. By following the chart below, you can make a composting litter layer only of the material on that soil area. Most of the time when dead plant material is mulched, it is a brown. There are ways to make 30:1 compost litter layer with only the materials available.
From the above chart , it is possible to get equal volumes of greens and browns from the same plants, but at differnt times of the year. Remember, when a plant is green with no flowers, it can be dried and it will remain a high nitrogen plants. Adding water to the green will revive it. When the plant has life cycled out and has created seeds, it is on its way out turning into a brown. Now you have the ingreadents of the perfect compost. Mulch that together and use it as a litter layer. The existing plants will canablize their own dead material for new growth. Think of dead plant material as potental building material for existing plants. If the material is similar to what is gorowning, then it is easier for the plant absorb and grow.
Differnt types of the Litter Layers
Grasslands with low to no canopy litter layers:
The quality of micro organisms move with the canopy available. When there is not much of a canopy layer, the bulk of the micro organisms are in the litter layer and a few inches down into the soil, depending on the type of plants available.
Forest and heavy understory canopy litter layers:
The quality of the micro organisms is raised in this case. Since a lot of the soil organisms are the same for leaves, there are more of them in thicken understory areas. That means your litter layer is higher than just the soil level. The litter layer is in the loose organic material and is mostly contained in the understory plants. This means less water escapes and more water is absorbed. This means the soil does not have to be as efficient in keeping water. This is why soil dries out when a heavy forest area has been cleared of trees and understory plants. The soil needs time to create a litter layer down in the soil.