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Nutrient excretion from cattle grazing nitrogen‐fertilized grass or grass–legume pastures
Author(s) -
Garcia Liza,
Dubeux José C. B.,
Sollenberger Lynn E.,
Vendramini Joao M. B.,
DiLorenzo Nicolas,
Santos Erick R. S.,
Jaramillo David M.,
RuizMoreno Martin
Publication year - 2021
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 - 10.1002/agj2.20675
Subject(s) - paspalum notatum , grazing , agronomy , avena , biology , trifolium repens , dry matter , secale , legume , cynodon dactylon , feces , excretion , zoology , brachiaria , red clover , forage , ecology , biochemistry
Nutrient cycling via livestock excreta is an important grassland ecosystem service. This study was conducted in 2016 and 2017 and determined nutrient excretion from cattle grazing three systems: (a) N‐fertilized bahiagrass ( Paspalum notatum Flüggé) overseeded with rye ( Secale cereale L.) and oat ( Avena sativa L.) during winter (Grass+N), (b) unfertilized bahiagrass overseeded with rye–oat–clover ( Trifolium sp.) mixture (Grass+clover), and (c) rhizoma peanut ( Arachis glabrata Benth.)–bahiagrass mixture overseeded with a rye–oat–clover mixture (Grass+CL+RP). Urinary volume excreted in the warm season ranged from 122 to 182 L ha −1 d −1 , more than double that in the cool season (56–70 L ha −1 d −1 ). Urinary N concentration during the warm season was greater in Grass+CL+RP compared with Grass+N (4.4 vs. 3.1 g kg −1 , respectively). In addition, fecal dry matter and organic matter output was greater for Grass+N than for steers grazing Grass+CL+RP during the warm season (3.8 and 3.2 vs. 2.8 and 2.2 kg hd −1 d −1 , respectively). Total annual feces excretion concentrations of P, K, Mg, and N were greater in the Grass+N than in Grass+CL+RP system. The introduction of legumes increased the proportion of N returning via urine. However, when summed across seasons, total N excretion (feces and urine) was greater in Grass+N than in Grass+CL+RP (89 vs. 71 kg ha −1 yr −1 ), mainly due to the greater stocking rate in the former. Grass–legume systems receiving 34 kg N ha −1 yr −1 recycled 80% of the N recycled in the grass system receiving 224 kg N ha −1 yr −1 , indicating the potential of forage legumes to add N to grasslands.