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Nitrogen and Grazing Affect Napier Grass Leaf Litter Biomass and Decomposition
Author(s) -
Apolinário Valéria X. O.,
Dubeux José C. B.,
Lira Mário A.,
Mello Alexandre C. L.,
Santos Mércia V. F.,
Muir James P.,
Viana de Freitas Erinaldo
Publication year - 2017
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/agronj2017.06.0308
Subject(s) - litter , pennisetum purpureum , agronomy , nitrogen , zoology , grazing , biomass (ecology) , plant litter , pasture , nutrient , chemistry , biology , ecology , dry matter , organic chemistry
Core Ideas Stocking rate reduced litter deposition. Management intensity affected litter decomposition. Nitrogen fertilization did not change litter deposition in grazed pastures.Stocking rate (SR) and N fertilization are important management practices that may alter nutrient cycling. We tested three SR [2, 3.9, and 5.8 animal units (AU) ha −1 ; 1 AU = 450 kg BW] and three N rates (0, 150, and 300 kg N ha −1 yr −1 ) on litter mass, chemical composition, and decomposition in a napier grass ( Pennisetum purpureum Schum.) pasture. Fertilizer rate did not change ( P = 0.4658) litter accumulation but decomposition after 254 d was greatest ( P ≤ 0.05) at the greatest management intensity. Litter mass was affected by a year × month interaction ( P ≤ 0.01), but in general the greatest litter mass occurred ( P ≤ 0.05) at the end of the growing season, and carried over to beginning of the next growing season. There was a SR × year interaction for litter mass. At 3.9 and 5.8 AU ha −1 , litter mass was greater in 2009 than in 2010. Visual observation indicated that in 2010 at the 3.9 and 5.8 AU ha −1 SR, the napier grass pasture was degrading, generating less biomass and consequently less litter than in 2009. In general, litter C/N ratio was above 30. There was no effect of SR ( P = 0.2684) or SR interaction with year ( P = 0.1558) on litter N concentration, with an average of 14 g N kg −1 . Our results indicated that napier grass management affect litter mass and C/N ratio. This has implications for litter decomposition and nutrient dynamics in these pastures.