HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bezdicek, D. F. Articles by Magee, B. H. Search for Related Content PubMed Articles by Bezdicek, D. F. Articles by Magee, B. H. Agricola Articles by Bezdicek, D. F. Articles by Magee, B. H.

Influence of Organic Nitrogen on Soil Nitrogen, Nodulation, Nitrogen Fixation, and Yield of Soybeans¹

ABSTRACT

Nitrogen was applied on a previous rye (Secale Cereale L.) cover crop for later determination of the effect of organic N on soybean (Glycine max L.) N₂-fixation rate, plant dry matter, N uptake, and yield. Nitrogen was applied at 0, 56, 112, and 224 kg N/ha as NH₄NO₃ or urea either on rye in mid-March or at soybean planting time in a 4 x 2 x 2 factorial design. In both years of study, N₂-fixation rate as estimated from acetylene reduction was reduced throughout the season by increased fertilization rate. For 1 year, interactions showed that N₂-fixation rate and nodule mass were stimulated late in the season from increased N fertilizer applied to the rye but not at soybean planting. Interactions between NH₄NO₃ and urea and time of application showed that NH₄NO₃ as compared with urea applied on rye significantly increased soybean dry matter, N uptake, and yield. Urea applied at planting increased these parameters in comparison with NH₄NO₃. The observed increases in dry matter, N uptake and yield from rye-applied NH₄NO₃ were not accompanied by a corresponding increase in N₂-fixation rate or nodule mass. This would suggest that the N₂ fixing system was not responsible for the increase of dry matter, N uptake, and yield. Soil organic N was not measurably influenced by the treatments imposed.

¹ Contribution no. 4795 and Scientific Article no. A1880 of the Maryland Agr. Exp. Sta., Dep. of Agronomy. Presented before Div. S-3, Soil Science Society of America, Miami, Florida, 1 Nov. 1972.

² Formerly Assistant Professor, Dep. of Agronomy, Univ. of Maryland, now Associate Professor, Dep. of Agronomy, Washington State Univ., Pullman; Faculty Research Assistant; and Agricultural Aide, Dep. of Agronomy, Univ. of Maryland, respectively.

Received for publication April 27, 1973. Accepted for publication October 31, 1973.