甘薯对不同形态氮素的吸收与利用

Absorption and utilization of different nitrogen forms for sweet potato

为探讨氮素形态对甘薯氮素吸收、利用及其氮素生产效率的影响。在大田生产条件下,分别施用酰胺态氮、铵态氮和硝态氮肥料,研究了甘薯生长发育过程中吸收根活力变化和氮素吸收动态、收获期氮素积累量和分配以及块根产量。结果表明,与酰胺态氮处理相比,铵态氮和硝态氮处理的吸收根活力和氮素积累起始势较高,氮素积累量、肥料氮素利用率及其生产效率也较高,块根产量提高了16.37%和10.52%。与硝态氮处理相比,铵态氮处理的氮素积累量较低,肥料氮素在块根中的分配比例较高,块根产量、氮素生产效率和肥料氮素生产效率分别提高了5.30%、13.28%和5.29%。甘薯施用铵态氮肥有利于高产和高效。

The objective of this study was to determine effects of nitrogen forms on nitrogen absorption and utilization,and nitrogen efficiency for storage root production in sweet potato.Three nitrogen forms CONH4N（urea）,NH＋4-N（NH4HCO3） and NO-3-N（CaNO3）,were applied in the field culture experiments,respectively.The changes of absorptive root activity and nitrogen absorption during sweet potato development,accumulation and distribution of nitrogen at the harvest,and yield of storage root were studied.The results show that absorptive roots are more vigorous in NH＋4-N or NO-3-N vs.CONH＋4-N treatment.Plants subjected to NH＋4-N or NO-3-N have a higher level of initial nitrogen,accumulate more nitrogen,and exhibit a higher level of nitrogen fertilizer use efficiency and15N production efficiency（i.e.storage root weight per unit fertilizer-nitrogen）.Plants treated with NH＋4-N or NO-3-N have 16.37% or 10.52% higher storage root yield compared to CONH＋4-N treated plants.Plants subjected to NH＋4-N accumulate lower nitrogen,and exhibit a higher level of15N distribution in storage roots.Plants treated with NH＋4-N exhibit 5.30% higher storage root yield,13.28% higher nitrogen production efficiency（i.e.storage root weight per unit nitrogen） and 5.29% higher15N production efficiency compared to NO-3-N treated plants.NH＋4-N is most suitable for obtaining high yield and high efficiency in sweet potato.