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Corn Responses to Post‐tasseling Nitrogen Deprivation and to Various Ammonium/Nitrate Ratios
Author(s) -
Reddy K.S.,
Mills H.A.,
Jones J.B.
Publication year - 1991
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1991.00021962008300010047x
Subject(s) - dry matter , nitrogen , ammonium , nutrient , nitrate , zea mays , chemistry , composition (language) , agronomy , zoology , biology , linguistics , philosophy , organic chemistry
Corn ( Zea mays L.) takes up more than half of its total N after tasseling. An experiment was conducted to determine how the availability of N and the N form, NH 4 or NO 3 , during the post‐tasseling period affect corn plant growth, ear development, and nutrient composition. In this experiment, corn hybrid ‘Pioneer 3343’ plants were grown hydroponically in pots outdoors with 50:50 NH 4 :NO 3 up to the emergence of tassels and then the plants were either deprived of N or changed to various ratios of NH 4 :NO 3 nutrition and grown to maturity. Nitrogen deprivation reduced both vegetative (stalk and leaf) and reproductive (cob, total kernel, and individual kernel) dry matter accumulation. Continuous supply of 50:50 ratio of NH 4 :NO 3 produced greater vegetative dry matter than changing to either higher or lower ratios of NH 4 :NO 3 . The ratio of NH 4 :NO 3 did not affect the ear dry matter production. Nitrogen deprivation decreased both leaf and kernel N concentration. While 50:50 NH 4 :NO 3 ratio increased the leaf N concentration, all NH 4 increased the kernel N concentration compared to other ratios. Nitrogen deprivation also reduced the concentrations of Mg, Fe, Mn, Zn, and B in the leaves but had no effect on the kernel nutrient composition. The cation and anion concentrations in the leaves and kernels were not according to the NH 4 and NO 3 effects (viz., uptake of cations greater and anions lower with NH 4 than with NO 3 nutrition), which were previously observed before tasseling. This difference may be due to a change in the uptake capacity for these nutrients after tasseling.