施肥对土壤及黄瓜中稳定性氮同位素丰度的影响

STUDY ON THE EFFECT OF DIFFERENT FERTILIZER ON THE STABLE NITROGEN ISOTOPE OF SOIL,LEAF AND CUCUMBER

研究不同肥料配施对土壤、黄瓜及其叶片中稳定性氮同位素丰度(1δ5N‰)及硝酸盐和硝酸还原酶活性的影响。结果表明,随着配施有机肥比例的降低,黄瓜中1δ5N呈现先低后高再低的趋势;各处理单施化肥初期时黄瓜中1δ5N与有机肥60%和40%配施处理间差异显著(P<0.05),中期时与有机肥60%、40%配施处理及对照间的差异显著(P<0.05),末期时与有机肥60%配施处理间有差异(P<0.05),与其他不同配施时差异不显著(P>0.05);相同处理的不同采摘时期黄瓜中1δ5N差异不显著(P>0.05)。不同处理时叶片与黄瓜间的1δ5N呈正相关(r=0.9836),其1δ5N主要受不同肥料配施处理的影响。随着有机肥比例的降低,黄瓜中硝酸盐含量逐渐降低,与黄瓜中1δ5N间的线性相关性差(r=0.6568);而叶片中硝酸还原酶活性逐渐提高,其中对照处理、100%、80%和60%有机肥处理时与叶片中δ15N丰度呈正相关(r=0.9187);60%、40%、20%有机肥和100%化肥处理时与叶片中1δ5N呈负相关(r=-0.9773)。总体来看,可以初步利用1δ5N作为标记来区分有机肥和化肥种植的黄瓜,但需要进一步研究1δ5N在作物中的分馏和分布规律。

The effect of combined application of organic and chemical fertilizers on stable nitrogen isotope abundance（δ^（15）N-‰）,nitrate and nitrate reductase active was studied for the soil,cucumber and leaf,respectively.The results showed that the δ^（15）N of cucumber was with the trend of low,high and low as the application rate of organic manure decreased,and it was significantly different（P0.05） between pure chemical fertilizer treatment with 60% and 40% organic manure treatment for the first sampling,also with CK for the second sampling,and only with 60% organic manure treatment for the final sampling,however which was not significantly（P0.05） for the other treatments.The δ^（15）N of cucumber was not significantly different during different harvest time（P0.05）for the same treatment.The correlation of δ^（15）N between the cucumber and the leaf was 0.9836 for the different treatment,whose δ^（15）N was more affected more by the fertilizer and less by the soil.The content of nitrate in cucumber was reducing with the rate of organic manure decreasing,which had a bad correlation（r=0.6568） with the δ^（15）N of cucumber;however the active of nitrate reductase was increasing which had a positive correlation with the treatments of control treatment,100%,80% and 60% of organic manure applied（r=0.9187）,and a negative correlation with the treatments of 60%,40%,20% of organic manure and 100% chemical fertilizer applied（r=-0.9773）.To sum up,the δ^（15）N can be used as marks to discriminate the cucumbers grown with organic manure and chemical fertilizer,but the pattern of fractionation and distribution of the stable nitrogen isotope should be further studied.