| Full text | |
| Author(s): |
Grassmann, Camila S.
;
Mariano, Eduardo
;
Diniz, Priscila P.
;
Borges, Beatriz M. F.
;
Borges, Clovis D.
;
Tsai, Siu M.
;
Rosolem, Ciro A.
Total Authors: 7
|
| Document type: | Journal article |
| Source: | SOIL BIOLOGY & BIOCHEMISTRY; v. 169, p. 12-pg., 2022-06-01. |
| Abstract | |
There is evidence that forage grasses such as Megathyrsus and Urochloa can suppress nitrification, with direct or indirect consequences on soil inorganic N dynamics and nitrous oxide (N2O) emissions. However, the influence of soil chemical properties on the dynamics of functional N-genes and losses of N in maize (Zea mays L.) inter cropped with forage grasses under N fertilization is poorly understood. In this study, soil samples and N2O emissions were analyzed from a field experiment in which maize (fertilized or not with ammonium-based fertilizer) was intercropped with Guinea grass (M. maximus cv. Tanzania), palisade grass (U. brizantha cv. Marandu), and ruzigrass (U. ruziziensis cv. Comum). Soil N-cycle microorganisms [16S rRNA of bacteria and archaea, nifH (gene encoding N2-fixing bacteria), ammonia-oxidizing bacteria (AOB) and archaea (AOA), nirS (encoding nitrite reductase), and nosZ (encoding nitrous oxide reductase)] were influenced by forage grass, N fertilization, and sampling time, but no evidence of biological nitrification inhibition was found. Palisade grass was associated with a higher abundance of nifH (7.0 x 105 gene copies g-1 soil, on average) in the absence of N compared with the other grasses (4.3 x 105 gene copies g-1 soil, on average). Nitrogen fertilization increased the abundance of AOB but not AOA. Furthermore, N2O flux was influenced by AOB, water-filled pore space, and N fertilization, whereas the cumulative N2O emission and fertilizer-induced emission factor (0.36%, on average) were not affected by the grasses. In conclusion, this study reveals the strong dominance of AOB under ammonium supply, potentially stimulating N2O emissions in maize-forage grass intercropping systems. (AU) | |
| FAPESP's process: | 15/50305-8 - A virtual joint centre to deliver enhanced nitrogen use efficiency via an integrated soil-plant systems approach for the UK & Brazil |
| Grantee: | Ciro Antonio Rosolem |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 16/25253-7 - Nitrogen dynamics in a cropping system with forages as cover crops and corn |
| Grantee: | Camila da Silva Grassmann |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 17/02517-1 - Nitrogen dynamics in a production system using Brachiaria as a cover plant |
| Grantee: | Eduardo Mariano |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |