施加不同量外源氮和互为伴生种下碱蓬和盐地碱蓬生物量变化的野外模拟实验

Biomass Changes of Suaeda glauca and Suaeda salsa under Reciprocal Companion and Different Additive Amount of Extraneous Nitrogen:A Field Simulation Experiment

2017年5月2日～6月27日,在黄河三角洲滨海湿地生态试验站中,采用野外模拟实验方法,布设了108根PVC管,在盐地碱蓬(Suaeda salsa)和碱蓬(Suaeda glauca)互为伴生种条件下,移栽两种植物,在每根管中,优势种的种植密度分别为4株和2株,伴生种的种植密度为1株;在无伴生种条件下,优势种的种植密度为1株。考虑黄河三角洲地区氮沉降情况,以尿素作为外源氮,设置了0 g/m^2氮、15 g/m^2氮和30 g/m^2氮3种外源氮输入量,开展了碱蓬和盐地碱蓬的生物量变化研究。研究结果表明,在有伴生种条件下,当每根PVC管中优势种的种植密度为4株和2株时,随着氮输入量提高,碱蓬和盐地碱蓬平均单株生物量都显著增高;在无伴生种的条件下,当外源氮输入量为15 g/m^2氮和30 g/m^2氮时,碱蓬生物量[(58.050±2.560) g/株和(58.740±3.170) g/株]显著高于无外源氮输入[(20.850±0.640) g/株],盐地碱蓬生物量[(82.640±1.330) g/株和(111.960±6.400) g/株]显著高于无外源氮输入[(37.500±1.750) g/株]。外源氮输入量提高促进了盐地碱蓬和碱蓬生物量的积累,盐地碱蓬生物量增加幅度更大,对盐地碱蓬生长的促进作用更强。

To reveal the biomass changes of Suaeda glauca and Suaeda salsa as reciprocal companion under different additive amount of extraneous nitrogen, a field simulation experiment was conducted in the Yellow River Delta ecology research station of coastal wetland from May 2 to June 27, 2017. The two species were transplanted in to PVC pipe, with overall 108 PVC pipes laid. There were 3 planting densities (4 plants of dominant with 1 plant of companion, 2 plants of dominant with 1 plant of companion, and only 1 plant of dominant) were set in the experiment. Considering the situation of nitrogen deposition in the Yellow River Delta, 3 kinds of additive amount of extraneous nitrogen (0 g/m^2 nitrogen, 15 g/m^2 nitrogen, 30 g/m^2 nitrogen) were set, urea was as the nitrogen resource of extraneous nitrogen. The results showed that the average biomass accumulation of Suaeda salsa and Suaeda glauca both enhanced significantly along with increasing extraneous nitrogen input when planted 4 plants of dominant and 2 plants of dominant in each PVC pipe. When the additive amount of extraneous nitrogen were 15 g/m^2 nitrogen and 30 g/m^2 nitrogen, the biomass of Suaeda glauca was (58.050±2.560) g per plant and (58.740±3.170) g per plant, which were both significantly higher than that [(20.850±0.640) g per plant] without extraneous nitrogen addition. The biomass of Suaeda salsa was (82.640± 1.330) g per plant and (111 .960±6.400) g per plant separately when the additive amount of extraneous nitrogen was 15 g/m^2 nitrogen and 30 g/m^2 nitrogen, which were also both significantly higher than that [(37.500± 1.750) g per plant] without extraneous nitrogen addition. Increasing additive amount of extraneous nitrogen promoted the biomass accumulation of Suaeda glauca and Suaeda salsa with an higher increase degree of the biomass of Suaeda salsa, indicating that increasing extraneous nitrogen promoted the growth of Suaeda salsa more strongly.