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Nitrogen‐Sulfur Relations in Soft White Winter Wheat. I. Yield Response to Fertilizer and Residual Sulfur 1
Author(s) -
Ramig R. E.,
Rasmussen P. E.,
Allmaras R. R.,
Smith C. M.
Publication year - 1975
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/agronj1975.00021962006700020012x
Subject(s) - straw , agronomy , crop , sulfur , nitrogen , yield (engineering) , human fertilization , fertilizer , sativum , crop rotation , ammonium nitrate , crop yield , chemistry , biology , materials science , organic chemistry , metallurgy
Sulfur deficiency occurs in some soils in the northwestern United States. Wheat ( Triticum aestivum L.) responses to S applications are highly variable and apparently related to N fertilization. Our objective was clarification of this variability by measuring yield responses of wheat (grain and straw) to S applied with a range of N (deficient to excess) for the first wheat crop and monitoring residual S effects on yields of three subsequent wheat crops. A factorial combination of four rates of S (0, 17, 34, and 68 kg S/ha) as gypsum and four rates of N (0, 45, 90, and 180 kg N/ha) as ammonium nitrate was applied to the first wheat crop at seeding. Wheat was grown in rotation with peas ( Pisum sativum L.), wherein the peas were not fertilized and subsequent wheat crops received only a blanket application of N at the optimum rate (56 kg N/ha). First wheat crops after fertilization did not respond to S when N was deficient or optimum. Sulfur applied with excess N increased straw but not grain yield. Significant N to S interactions were noted. Residual S increased straw yield in all wheat crops and grain yield in 1 of 4 second, 3 of 3 third, and 2 of 2 fourth‐wheat crops. All S application rates gave similar yield increases in the second wheat crop. Residual S from 17 kg S/ha gave responses below maximum in the third wheat crop and residual S from 34 kg S/ha was marginally adequate in the fourth wheat crop. Wheat response to residual S was influenced by N rates applied to the first wheat crop. High N and S fertilization resulted in early drought and curtailed yields. Gradual release of residual S from recent organic matter apparently provided S at a rate adequate for efficient water use and maximum yield.