Soil Respiration, Nitrification, and Denitrification in a Wheat Farmland Soil under Different Managements

A field experiment was conducted during the 2010 to 2011 winter wheat-growing season to understand the soil respiration (R-s), nitrification, and denitrification rates in winter wheat farmland soil under no-tillage (NT) treatment with rice straw incorporation. The experimental treatments include NT, NT with rice straw covers on the surface (NTS), conventional tillage (CT), and CT with straw incorporation (CTS). No-tillage and straw incorporation treatments did not change the seasonal patterns of R-s , gross nitrification (Gn), and denitrification (D) rates compared with CT. Compared with the CT treatment, the NT, NTS, and CTS treatments significantly reduced R-s (P < 0.01), and the NT and NTS treatments significantly increased Gn and D (P < 0.01). CTS also significantly increased Gn (P < 0.01) but had no significant effect on D (P > 0.05). Further analysis showed that the temperature sensitivity of soil respiration (Q(10)) of CT, NT, NTS, and CTS were 4.26, 1.86, 3.25, and 2.36, respectively. Our findings suggest that, compared with CT, the NT and straw incorporation treatments reduced R-s and Q(10) and increased Gn and D.