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Fate of Urine Nitrogen in Three Soils throughout a Grazing Season
Author(s) -
Decau M. L.,
Simon J. C.,
Jacquet A.
Publication year - 2003
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2003.1405
Subject(s) - lysimeter , leaching (pedology) , loam , soil water , pasture , grazing , lolium perenne , agronomy , zoology , nitrate , environmental science , chemistry , nitrogen , organic matter , urine , poaceae , biology , soil science , organic chemistry , biochemistry
The fate of 15 N‐labeled cattle ( Bos taurus ) urine (52 g N m −2 ), applied to a 0.4‐m 2 surface area on three dates between May and October to three different pasture soils, was studied using 2‐m 2 lysimeters. Over a period of two years, the sward recovered most of the 15 N, but the amount recovered decreased with application date (62% in spring to 17% in fall). However, N uptake by ryegrass ( Lolium perenne L.) in Year 2 showed that some nitrogen came from the previous year's urine application. The largest leaching losses of urine N resulted from the late application date. These losses mainly occurred during the first winter despite the small amount of water drainage. Soil type largely determined 15 N losses. The granitic Brunisol was the most freely draining and had the greatest leaching (up to 35% recovery of urinary N). In contrast, leaching in the silty loam Neoluvisol remained under 4% of 15 N applied. The Calcosol appeared to be susceptible to all kinds of N losses with intermediate unaccounted‐for N pool and leaching fractions and lesser utilization of urinary N by grass. Immobilization in soil organic matter, roots and litter, and stubble pools were not markedly influenced by the date of application or soil type. They amounted to 25 to 33, 2, and 2% of N applied as urine, respectively. In these climatic conditions with moderate drainage, leaching of water poor in quality for nitrate only occurred for late‐season grazing or on the granitic Brunisol, which was very vulnerable to leaching.