秸秆还田和氮肥用量对冬小麦产量和氮素利用的影响

王新媛,赵思达,郑险峰,王朝辉,何刚

Effects of Straw Returning and Nitrogen Application Rate on Grain Yield and Nitrogen Utilization of Winter Wheat

WANG XinYuan,ZHAO SiDa,ZHENG XianFeng,WANG ZhaoHui,HE Gang

图3 秸秆还田和氮肥用量对冬小麦收获期0—200 cm土层的土壤硝态氮残留量影响 箱形图的实线和虚线分别表示中位数和平均值。箱形图的上边界和下边界分别表示75%和25%的四分位数。箱形图的上缘和下缘分别表示95%和5%的百分位数。不同小写字母表示玉米秸秆不还田条件下不同氮肥用量的土壤硝态氮残留量差异显著（a）。不同大写字母表示玉米秸秆还田条件下不同氮肥用量的土壤硝态氮残留量差异显著（b）

Fig. 3 The effect of N application rate on soil NO3--N in 0-200 cm soil layer at winter wheat harvest with straw returning (a) and without straw returning (b) Solid and dashed lines in this figure indicate the median and mean, respectively. The box boundaries indicate the 75% and 25% quartiles, and the whisker caps indicate the 95th and 5th percentiles. Different small letters indicate that there is a significant difference between N application rate in controlling treatment (without straw returning) at P<0.05. Different capital letters indicate that there is a significant difference between N application rate in maize straw returning at P<0.05