| A field experiment was conducted to evaluated NH3 volatilization and N2 O emission fluxes from rice paddy fields at southeast Hubei in central China using venting method and static chamber gas chromatographic techniques, respectively. Analyze the impact of different types of nitrogen fertilizer and tillage on NH3 volatilization and N2 O emission rate of seasonal variation, aims to provide a scientific basis for guiding rational fertilization, improve nitrogen efficiency and reduce environmental paddy nitrogen pollution. Treatments were established following a split-plot design of a randomized complete block with N sources(no nitrogen(N0), inorganic nitrogen fertilizers(IF), organic nitrogen fertilizers(OF), organic with inorganic nitrogen fertilizer(OF+IF); slow-release fertilizer with inorganic fertilizer(SR+IF), as the main plot and tillage practices(tillage and no-tillage) as the split-plot treatment.Our main findings are as follows:(1) Accumulation of NH3 volatilization in no-tillage paddy was significantly higher than plowing paddy, increased by 9.6%. Compared with N0 treatment, nitrogen fertilizer application was significantly increased NH3 volatilization, and the cumulative NH3 volatilization in seedling stage is the largest in four stages after fertilization of the whole rice growth period, which occupied 74.8% ~ 84.7%. Compared with the IF treatment, OF, OF + IF and SR + IF reduced cumulative NH3 volatilization by 28.3%, 17.0% and 31.0%, respectively.(2) The way of cultivation has different influence on N2 O emissions within different treatments from paddy fields. Specific performance are: no-tillage treatments promoted N2 O emissions with the increase of 13.6% at IF treatment and 14.3% at OF+IF treatment; no-tillage treatments reduced N2 O emissions at SR+IF treatment by 16.1%; no-tillage treatments have no significant effects on N2 O emissions at OF treatment. Compared with N0 treatment, nitrogen application significantly increased N2 O emissions with a range from 273.3% to 633.0%, and the cumulative N2 O emissions in seedling stage is maximum value in four stages after fertilization of the whole rice growth period, which accounting for 54.5% ~ 77.7%. Compared with the IF treatment, SR+IF treatment significantly reduced the cumulative emissions of N2 O by 22.1%; OF+IF treatment significantly increased the cumulative emissions of N2 O by 52. 9%; OF has no significant difference in the cumulative N2 O emissions.(3) Compared with tillage, no-tillage teatments reduced N recovery efficiency(NRE) by 19.5%, but increased N physiological efficiency(NPE), N agronomic efficiency(NAE) and N partial factor productivity(NPFP) by 116.8%, 74.7% and 7.6% in paddy fields, respectively. Compared with IF treatment, OF treatment increased NRE by 63.6%, but reduced NPE, NAE and NPFP by 7.9%, 51.2% and 69.2%, respectively; OF+IF treatment increased NRE, NAE and NPFP by 74.0%, 87.8% and 13.5%, respectively; SR+IF treatment increased NRE, NAE and NPFP by 178.2%, 86.4% and 13.3%, respectively, while reduced 35.2% of the NPE.(4) Rice yield of no-tillage paddy was significantly higher than conventional tillage with an increase of 4.9%; OF+IF and SR+IF treatment own the highest yield of 9733 kg/ha and 9862 kg/ha compared with other treatments respectively, and increased production 11.8% and 13.3% compared with the IF treatment, respectively. Compared with the IF treatment, OF treatment significantly reduced the rice yield of 7.9%.(5) The correlation analysis showed that, NH3 flux had significantly positively correlated with ammonium nitrogen, inorganic nitrogen of soil and flood water. N2 O flux had a significant positive correlation with inorganic nitrogen of soil and flood water. NRE had significant negative correlation with NH3-N and total gaseous N loss. NPE had a significant positive correlation with NH3-N, N2O-N and total gaseous N loss.In summary, we conclude that: inorganic fertilizers with organic fertilizers can effectively reduce NH3 volatilization loss, improve nitrogen recovery efficiency and increase production. So this measure can be served as an effective stimulation to increase rice production, but coinstantaneously increased emissions of the greenhouse gas N2 O. Controlled release fertilizers with inorganic fertilizers can reduce NH3 volatilization loss and N2 O emissions, and improve nitrogen recovery efficiency and rice yield, can be used as an environmentally friendly fertilization program. |
PDF Full Text Request