Question

Discuss the soil conditions that are likely to cause plants to suffer phosphate deficiencies, and how plants have adapted to overcome these.

Answer 1

Plants cannot survive without phosphorus. It forms the backbone of many crucial molecules (such as DNA) and is a key player in energy transfer reactions. Low availability of phosphorus is a major environmental stress for plants and can lead to great losses in crop production.An organic fertiliser containing adequate amounts of each vital nutrient can also be used to ensure that your plants are receiving the proper levels of phosphorus that they require. Additionally, other sources of phosphorus can be added to the soil in order to maximise exposure. Good source of phosphorus include warm casting, fish meal, crab shell and soft rock phosphate. Overwatering and compact soil can also be causes of phosphorous deficiency.

Climatic and site conditions, such as

rainfall and temperature, and moisture and soil
aeration (oxygen levels), and salinity (salt
content/electrical conductivity) affect the rate of P
mineralization from organic matter decomposition.
Organic matter decomposes releasing P more
quickly in warm humid climates and slower in cool
dry climates.

Phosphorus is released faster when
soil is well aerated (higher oxygen levels) and much
slower on saturated wet soils.
Soils with inherent pH values between 6 and 7.5
are ideal for P-availability, while pH values below
5.5 and between 7.5 and 8.5 limits P-availability to
plants due to fixation by aluminum, iron, or calcium
often associated with soil parent
materials. Soil P cycles in many different forms
some that are readily available and some that are
not.

- Architectural adaptation: this adaptation is related to change in root branching, root length and formation of hair. This adaptation increases surface area for absorbing more nutritents from available soilPlants within a species that have larger roots are genetically advantaged and less prone to phosphorus deficiency.

- Morphological and biochemical adaptation that favours more uptake of phosphorus across the root surface.