What type of soil structure is considered the most desirable for crop production?

Answer 1

Vegetation rots down and creates humus which improves soil structure.

Answer 2

If the soil has lots of nutrients, then there is a lot of agriculture in that area. If there is little or no nutrients in the soil, then the plants cannot survive and agriculture is not possible in that area

Answer 3

This is actually quite a complex question. It covers elements of plant Biology and also partially saturated soil mechanics.

Plants draw water from the soil into their roots and up through the plant stem using two processes.

1. Osmosis, due to high concentrations of salts in solute within the roots. This water when drawn into the roots creates positive water pressure which forces water up through the "xylem" which is the plant tissue used to transport water.
2. Evapotranspiration from plant leaves creates tiny menisci in the fluid within the cells which in turn generates negative pore pressure / suctions within the cells where this transpiration occurs. This is known as transpirational pull and acts to draw water up from the roots.

In order for the water to be easily drawn from the soil in to the root of the plant it will ideally be below the water table or phreatic surface. This means that there are positive pore water pressures and the water pushes on the root from outside, while the osmotic gradient and transpiration pull act to draw or pull the water in. As such it is relatively easy for the plant to draw water into the roots.

However this becomes much more complicated where the roots are above the water table in the partially saturated zone (where there is both air and water within the soil pore spaces). Here the pore water pressures are negative (referred to as soil suction) where the lower the moisture content the higher the suction.

In this case the negative pore water pressures would act to try and pull water from the plant root and as such the plant will usually respond by stopping attempts to retrieve water from the roots within the partially saturated zone and try to extend downwards to the water table. This may not however be possible and may be considered a draught condition. Where this occurs the plant will reduce the water loss through transpiration by closing the "stoma" or pores in the leaf surfaces through which water can escape by transpiration in an effort to retain as much moisture as possible.

Answer 4

Soil structure is the natural aggregation of soil particles. The type of soil and size determines the movement of water through it and affects the crop production.

Answer 5

Depends entirely on the type of crop being produced.

For example rice, which is grown in water filled paddies of wheat which requires fairly well drained soil.