Provision Mechanism for Plant Nutrient

Some Plant Nutrient Requirements

During the period of growth and development, plants need some nutrients that include : Carbon ( C ), Hydrogen ( H ), Oxygen ( O ), Nitrogen ( N ), phosphorus ( P ), Potassium( K ), calcium ( Ca ), magnesium ( Mg ), sulfur ( S ), iron ( Fe ), manganese ( Mn ), boron ( B ), Mo, Copper ( Cu ), Zinc ( Zn ) and Chlorine ( Cl ). Nutrients are classified as Essential nutrients. This essential nutrient for plants based on the amount of their needs, grouped into two, namely :

1. the necessary nutrients the plants in large numbers called Macro Nutrient

2. plant nutrients required in small quantities called Micro Nutrients . Includes macro nutrients : N , P , K , Ca , Mg , and S. Micro nutrients include : Fe , Mn , B , Mo , Cu , Zn , and Cl.

Mechanism of Nutrient Supply

The supply of nutrients to the plant consists of three categories , namely:

1. is available from the air
2. available from plant roots absorb water
3. are available from the ground . Some nutrients are available in sufficient quantities of air are :
a. Carbon ( C )
b. Oxygen ( O )

which is in the form of carbon dioxide ( CO2 ). Available nutrients from water ( H2O ) are absorbed are: hydrogen ( H ), because the oxygen from water molecules undergo oxidation process and released into the air by plants in the form of molecular oxygen ( O2 ). As for other essential nutrients that plants need are available from the soil.

The mechanism of nutrient supply in the soil via three mechanisms , namely :
1 . The mass flow ( Mass Flow )
2 . diffusion
3 . Root interception

Mass Flow Mechanism

Mass flow mechanism is a mechanism of nutrient movement in the soil toward the root surface together with the movement of water masses. During the lifetime of the plant experienced the evaporation of water, known as transpiration events. During the process of plant transpiration takes place, there is also the process of absorption of water by plant roots. Mass movement of water to the plant roots a direct result of the mass uptake of water by plant roots also carry entrained nutrients contained in the water. Events availability of nutrients contained in the water to come with the mass movement of water to the surface of plant roots known as Mass Flow Mechanism. Nutrient availability to plants through this mechanism include : nitrogen ( 98.8 % ), calcium ( 71.4 % ), sulfur ( 95.0 % ), and Mo ( 95.2 % ).

Diffusion mechanism

Availability of nutrients to the surface of plant roots, can also occur due to concentration differences through the mechanism. The concentration of nutrients in the plant root surface is lower than the concentration of nutrients in the soil solution and nutrient concentration on the surface of colloidal clay and organic colloids on the surface. This condition occurs because most of the nutrients have been absorbed by plant roots. The high nutrient concentrations in the third position causes the occurrence of diffusion of highly concentrated nutrients to the plant root surface position. Nutrient movement events occur because of differences in nutrient concentration is known as diffusion mechanism of nutrient supply. Some nutrients are available through the diffusion mechanism , are: phosphorus ( 90.9 % ) and potassium ( 77.7 % ).

Interception mechanism Roots

Root interception mechanism is very different from the two previous mechanisms . Both previous mechanism explains the movement of nutrients to the roots of plants, while the third mechanism explains the movement of plant roots that shorten the distance with the presence of nutrients. This event occurs because the plant roots grow and elongate, thereby extending the reach of the roots. Extension of the roots closer to the root surface makes the position where the nutrients are, both nutrients are in the soil solution, the surface of colloidal clay and organic colloids surface. The mechanism of nutrient availability are known as root interception mechanism. Nutrient availability is largely through this mechanism are : calcium ( 28.6 % ).