春玉米田施用双氰胺和硫包衣尿素的节本减排效果分析

Effect of Dicyandiamide and Sulfur Coated Urea on Saving Cost and N_2O Emission Reduction in Spring Corn Field

氧化亚氮(N2O)是一种重要的温室气体,农田土壤是其重要的排放源。本研究利用温室气体自动测定系统,对华北平原春玉米农田尿素(U)、尿素添加10%双氰胺(DCD1)、尿素添加5%双氰胺(DCD2)、硫包衣尿素(SCU)和不施肥(CK)5个不同施肥处理土壤进行N2O测定,以分析双氰胺和硫包衣尿素对土壤N2O排放的影响。结果表明,(1)各处理N2O排放总量顺序为U>SCU>DCD2>DCD1>CK,各处理的排放系数在0.20%～0.71%,与单施尿素相比,DCD1、DCD2分别减少N2O排放59.5%、47.1%,硫包衣处理的N2O排放与尿素处理差异不显著,但两者的N2O排放均极显著高于添加DCD的处理(P<0.01)。(2)排放高峰是伴随土壤孔隙含水量(WFPS)明显上升而发生的,各施肥处理N2O的排放通量与土壤WFPS呈极显著相关关系(P<0.01)。(3)DCD2施肥方案每减排1tCO2-eq的同时可减少支出约178元,表明此方案可作为减少春玉米农田N2O排放的技术措施。

Nitrous oxide （N2O） is an important greenhouse gas and agricultural soil is a major source of N2O emission. Effect of different fertilization treatments on N2O emissions of spring corn fields in North China plain was continuously monitored using an automatic sampling and analyzing system. Fertilizer treatments included urea （U） , urea mixed with 10% and 5% by N -weight of dicyandiamide （DCD1, DCD2） , sulfur coated urea （SCU） , and non - fertilizer （CK）. Experiment results showed that, （ 1 ） the total N2O emissions of the five treatments were U 〉 SCU 〉 DCD2 〉 DCD1 〉 CK. The emission factors ranged from 0. 20% to 0. 71%. In DCD treated plots, soil N2O fluxes were 59.5% （DCDI） and 47.1% （DCD2） lower than N2O fluxes in urea plots. There was no significant difference between SCU plots and U plots on N2O fluxes. The N2O fluxes of SCU plots and U plots were significantly higher than DCD plots （P 〈0. 01）. （2） The peak of N2O emissions occurred while WFPS（Water Filled Pore Space） increased significantly, N2O fluxes of all treatments and soil WFPS correlated significantly （ P 〈 0. 01 ）. （3） The DCD2 treatment could save about 178 yuan while reducing It CO2 equivalent. It can be used as a technical measure to reduce N2O emissions from spring corn field.