Topsoil and subsoil C and N turnover are affected by superficial lime and gypsum application in the short-term

Barcelos, Jéssica P.Q. [UNESP]; Mariano, Eduardo [UNESP]; Jones, Davey L.; Rosolem, Ciro A. [UNESP]

Topsoil and subsoil C and N turnover are affected by superficial lime and gypsum application in the short-term

Data

2021-12-01

Autores

Barcelos, Jéssica P.Q.

Mariano, Eduardo

Jones, Davey L.

Rosolem, Ciro A.

Tipo

Artigo

Resumo

Alleviation of subsoil acidity with lime or gypsum increases carbon (C) accumulation in deep layers by stimulating root growth and C and nitrogen (N) inputs at depth. However, the effects of these amendments combined with N fertilization on soil CO2 emissions remain controversial. We evaluated the effects of superficial lime and gypsum application and N-fertilizer on C and N dynamics and microbial C use efficiency (MicCUE) in samples taken from the topsoil (0–10 cm) and subsoil (40–60 cm) of a no-till field experiment carried out in Brazil. We performed a short-term laboratory incubation with 14C-glucose and 14C-arginine to assess C and N mineralization dynamics. Liming increased topsoil pH but had no effect on subsoil acidity. A higher content of organic C, total N, and microbial biomass C and N were found in the topsoil. The addition of soil corrective (lime and gypsum) and N fertilizer had no effect on MicCUE of added 14C-glucose. However, the MicCUE of 14C-arginine was affected by the soil layer, and was higher in the subsoil. After the addition of arginine, net NH4+-N production was highest in the topsoil control, while net NO3−-N content was highest with lime + gypsum plus residual N in the same layer. We conclude that while lime and gypsum ameliorate soil acidity, they have minimal effect on C cycling through the microbial biomass, particularly in the subsoil.