soil- +

Fine-grained fertile earth deposited by water flowing over flood plains or in river beds: Keith and the other farmers near the mouth of the river found that the alluvial soils were much more fertile than the land farther away from the river.

Alluvial soil is rich and fertile earth and can be found in aquatic communities (living in or on water and is a substantial part of the life span and is generally restricted to fresh water or inland waters).

A type of earth that develops in arid, or dry, climates: Desert soils develop under sparse shrub vegetation in warm to cool arid climates with a light-colored surface soil usually underlain by calcareous material and a hardpan layer.

Desert soil is a soil variety typically found in arid climates, usually with little leaching and minimal humus content.

Desert soil is referred to as an "aridisol" in the nomenclature of the United States Department of Agriculture's Natural Resources Conservation Service.

Any soil consisting primarily of minerals: Mineral soils can contain sand, silt and clay materials rather than organic matter (composting and mulching).

Human excrement collected from non-flushable toilets or cesspools when it is dark outside: Night soil is especially use as fertilizer.

Well-drained soil which has developed under the dominant influence of the natural vegetation characteristic of a region; zonal soils of an area: When Jane planned her garden, she wanted to have phytomorphic soil to improve the earth for the best results of her vegetables.

Earth formed on a pre-existing landscape but which was not subsequently buried under younger sediments: It should be taken into account that relict soils may represent a wide range of time periods.

Earth that is unusable for agricultural purposes: Saline-alkali soil contains more than 15% exchangeable sodium, has a high content of soluble salts, and a pH of less that 9.5.

1. The portion of the earth's surface consisting of disintegrated rock and humus: Some plants cannot develop in poorly drained soils, but wither, droop, shrivel, and die.
2. All loose, unconsolidated, weathered, or otherwise altered surface material lying on the ground above bedrock: Specifically, soil is a natural accumulation of organic matter and inorganic rock material that is capable of supporting the growth of vegetation.
3. A particular kind of earth: Soil can also be sandy soil.
4. The ground when producing vegetation or as cultivated for its crops: Sam used fertile soil for his garden.
5. The biologically active, porous medium that has developed in the uppermost layer of the earth's crust: Soil is one of the principal substrata of life on the planet Earth, serving as a reservoir of water and nutrients as a medium for the filtration and breakdown of injurious wastes, and as a participant in the cycling of carbon and other elements through the global ecosystem.

Soil has evolved through weathering processes driven by biological, climatic, geologic, and topographic influences.
6. A country, land, or region: The criminal act was committed on American soil.
7. The ground or earth: Jeff, the farmer, was tilling their soil when it started to rain.
8. Any place or condition providing the opportunity for growth or development: Some people believe that poverty provides the soil for crime and social instability.

In agronomy, the substances added to the soil to improve plant growth; soil improvement; soil conditioner: Sam was informed that a soil amendment would be useful for improving the soil's physical qualities, like its fertility.

A mapping unit used in detailed soil surveys: A soil complex consists of two or more distinguishable soils in a given geographic area which are grouped together on the basis of their areal (area) distribution.

In geology, The air occupying the pore or open spaces in soil: Soil atmosphere can be a gas located in the pores or cavities in the soil or, in other words, in the zone of aeration.

Carbon contained in the solid surface layer of the Earth: The amount of soil carbon in the ground is a function of the historic vegetative cover and productivity, which in turn is influenced by climatic variables.

Any of various methods of land management that seek to protect the soil from erosion and chemical decay, so as to maintain its quality: The technique of strip cropping (alternating different crops) is one method of soil conservation because it is believed to provide almost total resistance to erosion.

The study of the relationship between the activities of soil organisms and the overall soil environment: Part of Jim's universities studies in biology included soil ecology in which he learned about the interactions between organisms and physical and chemical substances.

In geology, the detachment and transportation of topsoil by the action of wind and running water: At the seashore, Jeny noticed how much of the coastal line was influenced by soil erosion because, over time, the shoreline had been eaten away by the waves of the sea.