Pesquisa | SciELO

ABSTRACT The largest proportion of greenhouse gas (GHG) emissions in the Agriculture sector of the Brazilian national GHG inventory is derived from the large (>200 million head) herd of cattle. The greatest contribution to these emissions comes from the enteric methane from cattle, but the direct and indirect emissions of nitrous oxide (N2O) from cattle excreta and N fertilizer are responsible for approximately 9 % of all national anthropogenic GHG emissions. Ammonia (NH3) can be volatilized from N fertilizer and cattle excreta and deposited in sites remote from the source, constituting an indirect source of N2O. This study aimed to determine whether direct N2O emissions and NH3 volatilization from N-fertilized pastures were greater than those derived from a mixed grass-legume pasture without N fertilizer addition. Emissions of N2O and NH3 from excreta and N fertilizer from a Palisade grass (Urochloa brizantha cv. Marandu) monoculture fertilized with 2 × 60 kg N ha-1 yr-1 urea were compared to those from a mixed Palisade grass-forage peanut (Arachis pintoi) pasture. Dung and urine were collected from these cattle, and NH3 losses and N2O emissions from the excreta and from N fertilizer were monitored using static chamber techniques. Volatilization of NH3 and N2O emissions were found to be greater from urine than from dung. Ammonia losses from excreta and urea fertilizer were low, not exceeding 6.8, 1.1, and 4.7 % of the N applied as urine, dung, and fertilizer, respectively. The N2O emissions showed a tendency to be greater for the urine from the N-fertilized compared to the mixed grass-legume pasture, and the N2O emissions from the urine of the N-fertilized pasture ranged from 0.08 to 0.94 % of applied urine N. The N2O emission from the N fertilizer was at maximum 0.46 % of the applied N. The direct N2O emissions and the loss of NH3 by volatilization (indirect N2O emission) from the excreta of cattle grazing the mixed grass-legume pasture were similar to, or lower than, the grazed grass monoculture fertilized with 120 kg N ha-1 yr-1. As the mixed pasture received no N fertilizer and hence no GHG emission from its manufacture or application, introducing forage peanut to the Urochloa brizantha pastures shows potential to be responsible for lower GHG emissions than the N fertilized grass pasture. (GHG >200 200 (>20 head NO O (N2O NH (NH3 Nfertilized grasslegume legume addition cv Marandu 6 ha1 ha 1 ha- yr1 yr yr- grassforage Arachis pintoi techniques dung low 68 8 6.8 11 1.1 47 4 7 4. respectively 008 0 08 0.0 094 94 0.9 046 46 0.4 12 yr1. 1. application >20 20 (>2 (NH 6. 00 0. 09 04 >2 (> > (

ABSTRACT The limited temporal completeness and taxonomic accuracy of species lists, made available in a traditional manner in scientific publications, has always represented a problem. These lists are invariably limited to a few taxonomic groups and do not represent up-to-date knowledge of all species and classifications. In this context, the Brazilian megadiverse fauna is no exception, and the Catálogo Taxonômico da Fauna do Brasil (CTFB) (http://fauna.jbrj.gov.br/), made public in 2015, represents a database on biodiversity anchored on a list of valid and expertly recognized scientific names of animals in Brazil. The CTFB is updated in near real time by a team of more than 800 specialists. By January 1, 2024, the CTFB compiled 133,691 nominal species, with 125,138 that were considered valid. Most of the valid species were arthropods (82.3%, with more than 102,000 species) and chordates (7.69%, with over 11,000 species). These taxa were followed by a cluster composed of Mollusca (3,567 species), Platyhelminthes (2,292 species), Annelida (1,833 species), and Nematoda (1,447 species). All remaining groups had less than 1,000 species reported in Brazil, with Cnidaria (831 species), Porifera (628 species), Rotifera (606 species), and Bryozoa (520 species) representing those with more than 500 species. Analysis of the CTFB database can facilitate and direct efforts towards the discovery of new species in Brazil, but it is also fundamental in providing the best available list of valid nominal species to users, including those in science, health, conservation efforts, and any initiative involving animals. The importance of the CTFB is evidenced by the elevated number of citations in the scientific literature in diverse areas of biology, law, anthropology, education, forensic science, and veterinary science, among others. publications problem uptodate up date classifications context exception (CTFB http//fauna.jbrj.gov.br/, httpfaunajbrjgovbr http //fauna.jbrj.gov.br/ , jbrj gov br (http://fauna.jbrj.gov.br/) 2015 Brazil 80 specialists 1 2024 133691 133 691 133,69 125138 125 138 125,13 82.3%, 823 82 3 (82.3% 102000 102 000 102,00 7.69%, 769 7 69 (7.69% 11000 11 11,00 . 3,567 3567 567 (3,56 2,292 2292 2 292 (2,29 1,833 1833 833 (1,83 1,447 1447 447 (1,44 1000 1,00 831 (83 628 (62 606 (60 520 (52 50 users science health biology law anthropology education others http//fauna.jbrj.gov.br/ faunajbrjgovbr //fauna.jbrj.gov.br (http://fauna.jbrj.gov.br/ 201 8 202 13369 13 133,6 12513 12 125,1 82.3% (82.3 10200 10 00 102,0 7.69% 76 6 (7.69 1100 11,0 3,56 356 56 (3,5 2,29 229 29 (2,2 1,83 183 83 (1,8 1,44 144 44 (1,4 100 1,0 (8 62 (6 60 52 (5 5 http//fauna.jbrj.gov.br (http://fauna.jbrj.gov.br 20 1336 133, 1251 125, 82.3 (82. 1020 0 102, 7.69 (7.6 110 11, 3,5 35 (3, 2,2 22 (2, 1,8 18 (1, 1,4 14 4 ( 82. (82 7.6 (7. 3, (3 2, (2 (1 7. (7

RESUMO: Os objetivos deste estudo foram determinar taxas de deposição e decomposição de serapilheira em pastagens de Marandu (Urochloa brizantha cv. Marandu) sob a) três formas de suprimento de nitrogênio (N), b) em diferentes estágios de pastejo rotativo e c) comparar a constante de decomposição (‘k’) derivada de “litterbags” com os valores derivados das estimativas de serapilheira existente e depositada (técnica SED). Os três tratamentos de suprimento de N foram: sem ou com adubação nitrogenada (zero ou 150 kg N ha-1 ano-1) ou com a leguminosa Desmodium ovalifolium. Não houve diferenças significativas (p<0,05) entre a serapilheira existente e as taxas de deposição e decomposição da serapilheira entre os três tratamentos de N. A taxa de decomposição da serapilheira foi estimada usando a técnica SED para os 7 dias de pastejo e dois períodos subsequentes de 14 dias em cada ciclo de 35 dias. A taxa de decomposição da serapilheira foi (p<0,05) maior no segundo período de descanso (dias 21 a 35) em 0,089 g g-1 dia-1, do que no período de pastejo (0,038 g g-1 dia-1) e no primeiro período de repouso (0,040 g g-1 dia-1). A meia-vida média da serapilheira foi de 12 dias pela técnica SED, enquanto a estimativa dos “litterbags” foi de 136 dias. Os resultados mostram que as estimativas fornecidas pelos “litterbags” subestimam severamente a decomposição em relação à técnica SED, e preveem um acúmulo de serapilheira a longo prazo que não é observado.

ABSTRACT: The objectives of this study were to determine the rates of plant litter deposition and decomposition in Marandu pastures (Urochloa brizantha cv. Marandu) under a) three forms of nitrogen (N) supply, b) at different stages of rotational grazing and c) to compare the single-exponential decay constant (‘k’) derived from litterbags with values derived from estimates of deposited and existing litter (DEL technique). The three N supply treatments were: without or with N fertilization (zero or 150 kg N ha-1 yr-1) or with the legume Desmodium ovalifolium. There were no significant differences (p<0.05) between existing litter and rates of litter deposition and decomposition between the three N supply treatments. The litter decomposition rate was estimated using the DEL technique for the 7-day grazing periods and two subsequent 14-day periods in each 35-day grazing cycle. The litter decomposition rate was (P<0.05) higher for the second rest period (days 21 to 35) at 0.089 g g-1 day-1, than for the grazing period (0.038 g g-1 day-1) and for the first rest period (0.040 g g-1 day-1). The mean half-life of the litter was 12 days using the DEL technique while the estimate from the litterbags was 136 days. Results showed that estimates provided by litterbags severely underestimate the decomposition in relation to the DEL technique and predict a long-term accumulation of litter which is not observed.

Cód. do Índice	Elemento
ti	título do artigo
au	autor
kw	palavras-chave do artigo
subject	assunto (palavras do título, resumo e palavras-chave)
ab	resumo
ta	título abreviado da revista (ex. Cad. Saúde Pública)
journal_title	título completo da revista (ex. Cadernos de Saúde Pública)
la	código do idioma da publicação (ex. pt - Português, es - Espanhol)
type	tipo do documento
pid	identificador da publicação
publication_year	ano de publicação do artigo
sponsor	financiador
aff_country	código do país de afiliação do autor
aff_institution	instituição de afiliação do autor
volume	volume do artigo
issue	número do artigo
elocation	elocation
doi	número DOI
issn	ISSN da revista
in	código da coleção SciELO (ex. scl - Brasil, col - Colômbia)
use_license	código da licença de uso do artigo

Não foram encontrados documentos para sua pesquisa