减量施氮对玉米-大豆套作系统土壤氮素氨化、硝化及固氮作用的影响

雍太文,陈平,刘小明,周丽,宋春,王小春,杨峰,刘卫国,杨文钰

Effects of Reduced Nitrogen on Soil Ammonification, Nitrification, and Nitrogen Fixation in Maize-soybean Relay Intercropping Systems

Tai-Wen YONG,Ping CHEN,Xiao-Ming LIU,Li ZHOU,Chun SONG,Xiao-Chun WANG,Feng YANG,Wei-Guo LIU,Wen-Yu YANG

图2 不同种植与施氮方式下土壤硝化作用强度(仁寿大田, 2013) A: 玉米土壤。MMNN: 单作玉米不施氮; MMRN: 单作玉米减量施氮; MMCN: 单作玉米常规施氮; IMNN: 套作玉米不施氮; IMRN: 套作玉米减量施氮; IMCN: 套作玉米常规施氮。B: 大豆土壤。MSNN: 单作大豆不施氮; MSRN: 单作大豆减量施氮; MSCN: 单作大豆常规施氮; ISNN: 套作大豆不施氮; ISRN: 套作大豆减量施氮; ISCN: 套作大豆常规施氮。 横坐标轴为生育时期, 玉米生育时期分别为拔节期(V6)、大喇叭口期(V12)、抽雄吐丝期(VT)和成熟期(R6), 大豆生育时期分别为五节期(V5)、盛花期(R2)、结荚期(R4)、鼓粒期(R6)和成熟期(R8)。同一生育时期下, 相同种植模式不同氮水平间字母不同表明差异显著(LSD, P < 0.05)。

Fig. 2 Nitrifying capacities of soil under different N rates and planting patterns (field trial in Renshou, 2013) A: soil of maize strips. MMNN: monoculture maize with no N; MMRN: monoculture maize with reduced N; MMCN: monoculture maize with conventional N; IMNN: intercropped maize with no N; IMRN: monoculture maize with reduced N; IMCN: intercropped maize with conventional N. B: soil of soybean strips. MSNN: monoculture maize with no N, MSRN: monoculture maize with reduced N; MSCN: monoculture maize with conventional N; ISNN: intercropped maize with no N; ISRN: monoculture maize with reduced N; ISCN: intercropped maize with conventional N. The abscissa is for the growth stages, the growth stages of maize include jointing stage (V6), 12th leaf (bell stage, V12), tasseling stage (VT), full maturity (R6), and the growth stages of soybean include the fifth trifoliolate stage (V5), full bloom stage (R2), full pod stage (R4), full seed stage (R6), full maturity stage (R8). At the same growth stage, bars represented by different letters between N levels are significantly different under the same planting pattern (LSD, P < 0.05).