B. BAR-YOSEF,
E. BRESLER,
U. KAFKAFi
Fluxes of P uptake by corn (Zea mays L.) plants growing in the field under high and low P fertilization levels, were both predicted by an uptake model, and obtained experimentally in the field by a new technique. The computed fluxes were averaged over a period of 1 week to give values of 4.8 X 10~5 and 1.7 X 10~5 pg P cm~2 sec"1 at the high and low P levels in the soil, respectively. These values were lower than the experimental weekly average fluxes which, at the critical growth period (between the 5th and 7th weeks), equaled about 6.8 X 10~5 and 2.5 X 10~5 /j.g P cm ~ 2 sec"1 , correspondingly. The deviation of the real conditions prevailing in the field from those assumed in the model tended, qualitatively, to explain the discrepancy. It is shown that the computed flux of f uptake is more sensitive to variations in the soil than in the plant parameters.
B. BAR-YOSEF,
E. BRESLER,
U. KAFKAFi
Fluxes of P uptake by corn (Zea mays L.) plants growing in the field under high and low P fertilization levels, were both predicted by an uptake model, and obtained experimentally in the field by a new technique. The computed fluxes were averaged over a period of 1 week to give values of 4.8 X 10~5 and 1.7 X 10~5 pg P cm~2 sec"1 at the high and low P levels in the soil, respectively. These values were lower than the experimental weekly average fluxes which, at the critical growth period (between the 5th and 7th weeks), equaled about 6.8 X 10~5 and 2.5 X 10~5 /j.g P cm ~ 2 sec"1 , correspondingly. The deviation of the real conditions prevailing in the field from those assumed in the model tended, qualitatively, to explain the discrepancy. It is shown that the computed flux of f uptake is more sensitive to variations in the soil than in the plant parameters.