• ISSN 1008-505X
  • CN 11-3996/S

不同形态氮素添加下三江源区高寒草甸草场氮素分配与利用

Nitrogen allocation and utilization in alpine meadows of the Sanjiangyuan region under exogenous additions of different nitrogen forms

    摘要
  • 摘要:
    目的 研究三江源区高寒草甸牧草对不同形态氮素的吸收利用和残留氮素在土壤中的去向及分配，以期为制定三江源区高寒草甸草场养分科学添加方案提供理论依据。
    方法 于2020年6月至2021年9月，在青海省称多县高寒草甸试验站开展15N田间微区示踪试验，试验设置3个不同氮素形态处理，分别为 (15NH4)2SO4、Ca(15NO3)2、CO(15NH2)2，各处理的氮素施用量均为N 300 kg/hm2。分析了施肥当年和次年不同形态氮素在高寒草甸牧草地上部、地下部中的含量，及在0—15、15—30 cm土层土壤中的去向及分配。
    结果 1)在施肥当年，与Ca(15NO3)2、(15NH4)2SO4处理相比，CO(15NH2)2处理下牧草地上部氮素吸收量分别显著增加了 276.4%、48.1%，地下部分别显著增加了360.3%、129.2%；0—15 cm土层中的氮素残留量分别增加了275.6%、78.4%，15—30 cm 土层分别增加了240.1%、115.6% (P<0.05)。2)在施肥次年，与Ca(15NO3)2、(15NH4)2SO4处理相比，CO(15NH2)2处理牧草地上部分氮素吸收量分别显著增加了206.9%、66.1%，牧草地下部分显著增加了473.2%、234.4%；0—15 cm土层中氮素残留量分别显著增加了635.6%、129.5%，15—30 cm 土层分别显著增加了22.5%、188.2% (P<0.05)。3)在施氮当年，(15NH4)2SO4和Ca(15NO3)2处理氮素去向表现为：15N损失量>15N土壤残留量>15N植物吸收量，而CO(15NH2)2处理为：15N土壤残留量>15N植物吸收量>15N损失量；在施氮次年 (15NH4)2SO4和Ca(15NO3)2处理的氮素去向为：15N损失量>15N植物吸收量>15N土壤残留量，而CO(15NH2)2处理为：15N植物吸收量>15N损失量>15N土壤残留量。
    结论 外源添加CO(15NH2)2能保证较高的氮素吸收率、较低的损失率，且残留氮素能发挥较好的后效作用，因此酰胺态氮为三江源区高寒草甸草场优选的氮素形态。

     

    Abstract:
    Objective We studied the absorption and utilization of different N forms by alpine meadow plants, and the fate of residual N in the soil to provide a theoretical basis for efficient and environmentally friendly fertilization of alpine meadows in the Sanjiangyuan area.
    Methods A field microplot experiment was carried out using the 15N tracer method at the Alpine Meadow Experimental Station in Chengduo County, Qinghai Province, from June 2020 to September 2021. The three N sources tested were (15NH4)2SO4, Ca(15NO3)2, and CO(15NH2)2, applied at N 300 kg/hm2 in early 2020. The N content and uptake in the above- and under-ground parts of forages were measured, and the N content in the 0–15 cm and 15–40 cm soil layers was analyzed in 2020 and 2021.
    Results 1) In the same year of N application, compared with Ca(15NO3)2 and (15NH4)2SO4, CO(15NH2)2 increased N absorption by 276.4% and 48.1% in the aboveground part, 360.3% and 129.2% in the underground part of forages, 275.6% and 78.4% for the N residual amount in the 0–15 cm soil layer, and 240.1% and 115.6% in the 15–30 cm soil layer (P<0.05) . 2) In the following year of N application, compared with Ca(15NO3)2 and (15NH4)2SO4, CO(15NH2)2 increased the N absorption in the aboveground part by 206.9% and 66.1%, 473.2% and 234.4% in the underground part of forages, 635.6% and 129.5% for residual N amount in 0–15 cm soil layer, and 22.5% and 188.2% in 15–30 cm soil layer (P<0.05). 3) In the same year of N application, the fate of (15NH4)2SO4 and Ca(15NO3)2 were in the order 15N loss>15N soil residue>15N plant uptake and 15N soil residue>15N plant uptake>15N loss for CO(15NH2)2. In the following year of N application, the fate of (15NH4)2SO4 and Ca(15NO3)2 were: 15N loss>15N plant absorption>15N soil residue and 15N plant absorption>15N loss>15N soil residue for CO(15NH2)2.
    Conclusion CO(15NH2)2 promotes a high nitrogen uptake rate by forages, lower loss rate, and higher soil residual nitrogen. Therefore, it can be used as the preferred nitrogen form in the alpine meadow pasture in the Sanjiangyuan region.

     

    • HTML全文
    • 参考文献(55)
    • 相关文章
    • 施引文献
  • 资源附件(0)

/

返回文章
返回