backtracker
Well-Known Member
How does excess amounts of nitrate affect the growth of a plant and why is this so?
Increase in nitrate, like increase in any salt will increase the osmotic concentration of the soil solution. The roots of the plant then have to take up minerals from a more and more concentrated solution. If the solution outside gets too concentrated, there will come a point where the plant is not able to take up any water against the concentration gradient and the plant will start to wilt. Even before this point is reached, the plant will grow slower.
When plants are irrigated in arid areas, the salts from the irrigation water become concentrated in the soil and the soil can become "saline" and no longer fertile. So the effect you have observed is very important in some areas of the world.
If farmers apply too much fertilizer, then it cannot be taken up be plants fast enough, or retained by the soil, so there is a danger that it will be washed through into the drainage water and get into the rivers. If this happens then algal growth (and the growth of other water plants) in rivers can be stimulated and the result is eutrophication. This is another reason for not applying too much nitrate.
As the amount of fertilizer is increased, the amount of extra yield is reduced...each extra kg of fertilizer produces less extra crop. There comes a point where the value of the extra crop is less than the cost of the extra fertilizer. Another reason to only apply the right amount of fertilizer and not too much.
John Hewitson
From a site in the UK.
Increase in nitrate, like increase in any salt will increase the osmotic concentration of the soil solution. The roots of the plant then have to take up minerals from a more and more concentrated solution. If the solution outside gets too concentrated, there will come a point where the plant is not able to take up any water against the concentration gradient and the plant will start to wilt. Even before this point is reached, the plant will grow slower.
When plants are irrigated in arid areas, the salts from the irrigation water become concentrated in the soil and the soil can become "saline" and no longer fertile. So the effect you have observed is very important in some areas of the world.
If farmers apply too much fertilizer, then it cannot be taken up be plants fast enough, or retained by the soil, so there is a danger that it will be washed through into the drainage water and get into the rivers. If this happens then algal growth (and the growth of other water plants) in rivers can be stimulated and the result is eutrophication. This is another reason for not applying too much nitrate.
As the amount of fertilizer is increased, the amount of extra yield is reduced...each extra kg of fertilizer produces less extra crop. There comes a point where the value of the extra crop is less than the cost of the extra fertilizer. Another reason to only apply the right amount of fertilizer and not too much.
John Hewitson
From a site in the UK.
