不同频次刈割对羊草碳、氮、磷化学计量特征的影响

Effects of Different Frequency Mowing on C,N and P Characteristics of Chemical Measurement of Leymus chinensis

以生长季中期羊草成熟叶片为试材,采用C/N元素分析仪和钼蓝比色法测定其C、N、P元素浓度,并计算C、N、P化学计量比值,分析了不同频次的刈割处理对羊草C、N、P化学计量特征的影响,以期揭示刈割对植物养分状况的影响。结果表明:刈割后羊草叶片C浓度与对照(不刈割)相比有降低的趋势,N、P元素浓度有显著升高的趋势。随着刈割频次的加重C浓度逐渐降低,不同刈割频次间差异不显著;N、P浓度随着刈割强度的增加逐渐升高。刈割后C/N和C/P与对照相比显著下降,且随刈割频次的加重,比值逐渐变小,刈割频次间差异不显著。刈割后N/P与对照相比也有下降的趋势,且随刈割频次的加重,比值逐渐变大。对照与不同频次刈割处理的N/P均大于16。说明不同频次刈割对羊草叶片N/P的影响很小,羊草生产力主要受P元素限制。高频次的刈割会导致生物量下降,养分流失严重,植物生长速度与植物氮和磷的利用效率受到影响,刈割1年休1年是最好的管理措施。

Via the analysis of the C,N and P elements concentration in Leymus chinensis leaves of the growing season medium-term,using the C/N element analyzer measurement and molybdenum blue colorimetric method to determine the concentration of C,N,P element,and calculate the C,N and P the stoichiometric ratio,different frequency of mowing treatment on L.chinensis C,N and P characteristics of chemical measurement were studied.The results showed that after mowing Leymus chinensis leaf C concentration compared with control（not mowing）had a tendency to reduce,N,P element concentration had a tendency to rise.As mowing frequency increasing C concentration decreased gradually,no significant difference between different mowing frequency;N and P concentration increased with the increase of mowing intensity.After mowing C/N and C/P compared with contrast decreased significantly,and with the increase of mowing frequency,the ratio gradually became smaller,no significant difference between the mowing frequency.After mowing N/P compared with control also had a downward trend,and with the increase of mowing frequency,the ratio increased gradually.Control with different frequency tationally cutting processing of N/P were greater than 16.Showed different frequency of mowing on L.chinensis leaves N/P was small,the influence of L.chinensis productivity was mainly restricted by P element.High frequency of mowing could cause lead to decreased biomass,plant growth and plant nitrogen and phosphorus use efficiency affected,cradling an annual leave one year was one of the best management practices.