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The Effect of Nitrogen and Phosphorus Fertilization on the Nitrogen Absorption by Sunflowers
Author(s) -
Loubser H. L.,
Human J.J.
Publication year - 1993
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1111/j.1439-037x.1993.tb01054.x
Subject(s) - human fertilization , phosphorus , nitrogen , agronomy , chemistry , factorial experiment , crop , horticulture , zoology , biology , mathematics , statistics , organic chemistry
I. Abstract Little is known about the effect of fertilization on the N uptake of sunflowers. A 4 2 factorial trial with 0, 60, 120 and 180 kg N ha −1 and 0, 15, 30 and 45 kg P ha −1 was conducted over three years. The N content and concentration of leaves, stems and capitula were determined at three growth stages. High N levels increased the N content and concentration of all plant parts at all growth stages sharply. High P levels increased the N content of all plant components through better growth. P has an inconsistent effect on N concentration but tended to decrease it. After flowering the crop assimilated 20 to 25 % of the total N. This implies that N applied can still be applied and utilized by the crop at a late stage. This should be substantiated by further research.