科尔沁沙地苜蓿根系C、N、P含量对最迟刈割时间的响应

Responses of C、N、P Content of Medicago Sativa root System to the Latest Cutting time in Horqin Sand Land

在相同刈割留茬高度的条件下,探讨霜前最迟刈割时间对根系C、N、P、C/N、C/P和N/P的影响规律,并对其相关性进行分析.结果表明:根系全C含量随最迟刈割时间的延迟呈现先增加后降低的变化趋势,最高值出现在9月7日刈割条件下;全N和全P含量随最迟刈割时间的变化规律基本一致,呈现逐渐降低的变化趋势,最高值均出现在8月23日刈割条件下;N/P比值相对比较稳定,不同刈割时间之间没有表现出显著差异;C/P和C/N相对N/P比值其稳定性较差,随着刈割时间的变化表现出一定差异,且9月7日和9月14日刈割条件下C/P和C/N均要高于其他时间刈割;C含量与各项指标之间相关性均不显著,P和N与各项之间(除N/P之外)均表现出显著或极显著相关关系,说明根系中C、N、P、C/N、C/P和N/P在一定条件下被N和P含量的影响要高于C.

Under the same condition of the latest cutting height,Setting the different treatment time conditions before frost for the latest cutting(8-23,8-31,9-7,9-14and9-21).testing C、N、P content of root system and calculating C/N、C/P and N/P,To discuss the influence regulation of C、N、P、C/N、C/P、N/P content of root system to the latest cutting time before frost and the correlation analysis.To provide theoretical reference for artificial grassland management of Medicago sativa in Horqin sand land.The results showed that the total carbon content of root system present first increase then decrease with the latest cutting time delay,the total carbon content of root system reached the maximum in the treatment of 9-7.the change rules of total nitrogen and total phosphorus content are basically identical with the latest cutting time delay,present gradual decrement trend,both of the maximum all appear in the treatment of 8-23.The N/P content of root system compared relatively stable and showed no significant difference in the different treatment time conditions,To compare N/P the C/N and C/P indicate less stability and there was a difference during the latest cutting time delay,in the cutting treatment of 9-7and 9-14 are higher than the other cutting time,there was no significant correlation between the Carbon content and other indicators,the nitrogen and phosphorus showed significant or extremely significant correlation with other indicators(except N/P),it illustrates the effect of N and P content are higher than the C content to the regulation of C、N、P、C/N、C/P、N/P content of root system Under certain conditions.