Maintenance of N cycling gene communities with crop-livestock integration management in tropical agriculture systems

Autor(es)

Rosa Portilho, Irzo Isaac ^[1] ; Savin, Mary Cathleen ^[2] ; Borges, Clovis Daniel ^[3] ; Tsai, Siu Mui ^[3] ; Mercante, Fabio Martins ^[4] ; Roscoe, Renato ^[5] ; de Carvalho, Laercio Alves ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Mato Grosso do Sul, BR-79804970 Dourados, MS - Brazil

^[2] Univ Arkansas, Dept Crop Soil & Environm Sci, Fayetteville, AR 72701 - USA

^[3] Univ Sao Paulo, Ctr Nucl Energy Agr, BR-13414970 Piracicaba, SP - Brazil

^[4] Embrapa Western Agr, BR-79804970 Dourados, MS - Brazil

^[5] Reg Council Engn & Agron Mato Grosso Sul CREA, BR-79010480 Campo Grande, MS - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AGRICULTURE ECOSYSTEMS & ENVIRONMENT; v. 267, p. 52-62, NOV 15 2018.
• Citações Web of Science: 1

Resumo

Five different agricultural management systems and a forest fragment at two farms were investigated for effects on soil bacterial indicators. This study was conducted in southern Mato Grosso do Sul, Brazil, in January 2014, at two farms that incorporated integrated crop-livestock systems in Hapludox soil. Impacts of management were assessed through evaluation of functional bacterial communities using quantitative PCR (qPCR) of nitrogen cycling genes (amoA, nirK, and nosZ), PCR-DGGE of the nirK community composition, and by investigating relationships of the nirK community with soil properties. The nirK gene community showed that reference forest soil maintained relatively large nirK, nosZ, but small amoA gene abundances and large range weighted nirK richness (Rr). The introduction of pasture into crop-livestock integration management (inclusion of the second and third year of grazing within a crop-livestock integration system, CL-2 and CL-3, respectively) or the field in its first year of crop rotation after grazing pasture (CL-b) increased nosZ and amoA abundance. Three years of grazing pasture in crop-livestock integration (CL-a) increased nirK abundance, while multiple years of crop rotation in crop-livestock integration management systems increased soil OM and promoted a richer nirK community composition. The nirK community Rr that was not significantly different from the forest was observed in the second or third year of crop rotation after grazing (CL-c or CL-d, respectively) and (CL-3). In contrast, fields in pasture (CL-a, continuous pasture (CP)) and the first year of crop rotation after pasture (CL-b) had reduced Rr and functional organization curves, indicating communities less resilient to future stress. Management systems under integrated crop-livestock farming in tropical soil maintained a relatively diverse N cycling bacterial community, possibly promoting soil quality and N cycling processes. (AU)

• Processo FAPESP: 15/21893-9 - Produção de N2O em solos cultivados com cana-de-açúcar: influência da abundância e composição microbiana
• Beneficiário: Clovis Daniel Borges
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 14/50320-4 - Dimensões US-BIOTA - São Paulo: pesquisa colaborativa: integrando as dimensões da biodiversidade microbiana ao longo de áreas de alteração do uso da terra em florestas tropicais
• Beneficiário: Tsai Siu Mui
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático