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Root-induced spatial variation in soil water content and its effect on phosphorus uptake and growth of pearl millet Pennisetum americanum { L.} Leek under drought conditions



A project entitled “Root-induced spatial variation in soil water content and 
its effect on phosphorus uptake and growth of pearl millet Pennisetum 
americanum { L.} Leek under drought conditions” lead by Prof. Dr. Dr.h.c.H. 
Marschner, of Institut für Pflanzernerährung, Universtat Hohenheim, 
Deutschland, in partnership with other scientific institutions in France, 
Mali, Chad, Senegal, Burkina Fasso and Benin was carried out under the 
European Union (D.G.XII) STD2 scientific programme.

This project aimed at understanding the interrelationship between water 
availability and phosphorus uptake by the pearl millet (Pennisetum americanum 
L.) in order to be able to define the best strategy for phosphorus 
fertilization under drought conditions. Experiments were carried out under 
controlled conditions in growth chambers.

The researchers reached the conclusion that an increase in phosphorus supply, 
by promoting shoot growth in a larger extent than root growth, will result in 
increase water requirements. Therefore, unless satisfaction of water 
requirements is possible, one must be careful to the extent of phosphorus 
supply.

It was also concluded that soil water might be limiting well above the well 
known lower limit of soil water holding capacity (wilting point); as roots 
uptake water, regions of lower water content are created, originating a large 
variability in soil water content. Under these conditions, hydraulic lift can 
no longer assure nutrient uptake. 

The conclusions reinforce previous knowledge of interaction that exists among 
water use and nutrients uptake. They are particularly innovative in what 
concerns these crop with special interest in tropical regions. They also have 
added value of cautioning against the common practice of recommending as a 
general practice phosphorus fertilization as a measure to increase 
productivity. This is only true if water compensates for the increase 
transpiration that accompanies increased growth.

Within this project several publications have been issued.

For further information please contact:

Prof. Dr. Dr.h.c.H. Marschner
Institut für Pflanzernerährung
Universtat Hohenheim
P.O.Box 70056210,
700 Stuttgart 70,9470 Deutschland.

CONTRACT TS2- A -068