To obtain a drip irrigation fertilization model for high yield,water-saving,and nitrogen oxide(N2O)emission reduction in sugarcane,as well as explore how different drip irrigation fertilization models affect the relevant factors of nitrogen oxide emissions in sugarcane field soil.Two drip irrigation water levels were set up in the field experiment:W1:60%～70%field water capacity(θf)during the seedling and mature stages,and 70%～80%θf during tillering and elongation stages;W2:70%～80%θf during seedling and maturity stages,and 80%～90%θf during tillering and elongation stages.And two drip irrigation fertilization levels:D1:N 250 kg/hm2,P2O5 150 kg/hm2,K2O 200 kg/hm2,and D2:N 300 kg/hm2,P2O5 180 kg/hm2,K2O 240 kg/hm2.The soil N2O emission flux,ammonium nitrogen(NH4+-N),nitrate nitrogen(NO3+-N)content,urease(URE),nitrate reductase(NR),nitrite reductase(NiR)and hydroxylamine reductase(HyR)activity in sugarcane fields were measured in different treatments of sugarcane yield,water use efficiency,and four different growth stages(seedling stage,tillering stage,elongation stage,maturity stage).The sugarcane yield of the W2D1 treatment was the highest,reaching 97.0 t/hm2.The water use efficiency of W1D2 and W2D1 treatments was better,reaching 21.46 kg/m3 and 20.59 kg/m3,respectively.At the tillering stage,the activities of NR,NiR,and HyR in all treatments basically reached the maximum,and the denitrification enzyme activity in the W2D1 treatment was higher.There is a significant positive correlation between N2O emission flux in sugarcane field soil and the activities of URE and NiR,with correlation coefficients of 0.502 and 0.709,respectively.There is a significant negative correlation between N2O emission flux and NO3--N content and NR activity,with correlation coefficients of-0.581 and-0.591,respectively.This indicates that the NO3--N content,URE,NR,and NiR activities in sugarcane field soil significantly affect N2O emission flux.W2D1 treatment(70%～80%θf during seedling and mature stages.80%～90%θf during tillering and elongation stages.N 250 kg/hm2,P2O5 150 kg/hm2,and K2O 200 kg/hm2)is the optimal drip irrigation fertilization mode,which can improve sugarcane yield and water use efficiency,and have important significance for N2O emission reduction.
Sugarcane yieldIrrigation and fertilizationNitrous oxideInorganic nitrogen contentEnzyme activity
NETL
NSTL
维普
万方数据
