Self-regulation of nutrient assimilation

In the soil close to the roots (rhizosphere) there is much greater release of potassium, phosphorus and nitrogen than in the soil that is a long way 

Methods for determining nutrient requirements Soil testing 

Soil testing is a widely used means of finding out the specific properties and nutrient content of a soil and monitoring them over a period of time (see Chapter 2 Planning and setting up an organic production unit). A fertilizer programme can be drawn up on the basis of the results of soil analysis. 

THE METHOD EOR DETERMINING N REQUIREMENTS. Mineral nitrogens (N J include nitrate (NOj ), nitrite and ammonia (NH ). Nitrite is an intermediate in nitrification and denitrification and occurs in negligible amounts in the soil. The amount of ammonia is highly dependent on soil pH and increases with increasing acidity. 

TIMING OE N i ANALYSES. analyses should be performed around the 

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