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Response of Irrigated Corn to Time, Rate, and Source of Applied N on Sandy Soils 1
Author(s) -
Jung P. E.,
Peterson L. A.,
Schrader L. E.
Publication year - 1972
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/agronj1972.00021962006400050035x
Subject(s) - sowing , nitrogen , urea , zoology , grain yield , soil water , agronomy , nitrate reductase , chemistry , zea mays , nitrate , yield (engineering) , poaceae , plant tissue , biology , botany , materials science , ecology , biochemistry , organic chemistry , metallurgy
To maximize N recovery by corn ( Zea mays L.) on irrigated sandy soils, establishing the proper time for and rate of N application are essential. Three sources of N (urea, NH 4 ,NO 3 , and KNO 3 ) were applied to corn at four rates (56, 112, 168, and 224 kg/ha of N) and six times application in all combinations. ‘Wisconsin 273’ (85 R.M.) and ‘Wisconsin 433’ (95 R.M.) were grown. Response was measured as grain yield, tissue yield (aerial portion at early dent), percentage N in tissue, percentage N in grain, and N uptake The N applied during either the 5th, 6th, 7th, or 8th week after planting was the most effective as shown by increased grain and tissue yields. Nitrogen applied after the 8th week was associated with a distinct reduction in N uptake and grain and tissue yields. Generally, percentage N in the grain and tissue increased with later N applications. The responses to urea and NH 4 NO 3 were similar and both sources were sig~fificantly better than KNO 3 . Nitrate reductase (NR) activity in the leaves and percentage N in grain and tissue increased with increasing rate of applied N. Yields of grain and tissue for Wisconsin 273 and Wisconsin 433 leveled off at the 112 and 168 kg/ha rates of N, respectively.