| The Administrative Committee of Xiongan New District of Hebei issued a bulletin,hoping that all sectors of society can put forward targeted treatment plans for the comprehensive utilization of Phragmites australis.Most of the schemes focus on how to improve the economic benefits of reeds.Few people make rational distribution and use of resources from the perspective of giving full play to the ecological functions of reeds in Baiyangdian Lake.At present,Baiyangdian reeds has different management modes in different areas,such as harvesting,no harvesting and burning.However,there is no specific study on the impact of different management modes on the growth characteristics of Baiyangdian reed and the ecological functions such as nitrogen and phosphorus absorption.In order to reveal the effects of different management methods on the growth characteristics and ecological functions of reeds in Baiyangdian,from April to November2017,we sampled the reeds of Baiyangdian and unharvested areas every half month,and collected two at the end of the reed growth period.Soil samples from two plots(0-40 cm)were collected at the end of the growth period of reeds,and the growth characteristics(including density,plant height and diameter)of reeds were observed and counted respectively during the The contents of nitrogen and phosphorus in reed components and soil layers were measured,and the reserves of nitrogen and phosphorus in reed were calculated to compare the two plots.The results showed that the density of reeds in harvested plots was higher than that in non-harvested plots during the investigation period,and there were significant differences among the three sampling times.The plant height of reeds in harvested plots was lower than that in non-harvested plots from April to June,and gradually exceeded that in non-harvested plots after July,but did not reach significant level in sampling.The diameter of reeds in harvested plots was higher than that in unharvested plots,and 7 of 11 sampling times had significant difference.The biomass and net photosynthetic rate of reeds in harvested plots were higher than those in non-harvested plots.The difference of biomass was not significantfrom April to June in the early growth stage.The difference increased gradually after mid-July.The difference reached significant level in four sampling periods of July 19,August 30,September 15 and November 3.The difference of net photosynthetic rate reached significant level in three sampling periods of April 25,May 12 and August 3.Level.Although the total nitrogen and phosphorus content of reed in the early growth period(April-May)was lower than that in the non-harvested area,the total nitrogen and phosphorus reserves of reed in the harvested area were higher than those in the non-harvested area due to the higher biomass.The nitrogen and phosphorus reserves of leaf and stem were significantly different in the peak growth season(July-August).Reed harvesting can not only significantly reduce the total nitrogen and total phosphorus content in surface soil(0-10 cm),but also affect the vertical distribution of total nitrogen and total phosphorus content in soil.The average content of total nitrogen and total phosphorus in different depths of soils in the harvesting area(0-40 cm)was lower than that in the uncultivated area.The surface soil was the most obvious(0-10 cm).The difference of total nitrogen content between the harvesting area and the uncultivated area reached a significant level,while the total phosphorus content between(0-10 cm)and(>10-20 cm)soil layers was significant.In addition,the content of total nitrogen and total phosphorus decreased with the increase of soil depth.The sample plots of harvesting area and non-harvesting area were burned in winter of2017,so they were changed to burning harvesting area and non-harvesting area when they were sampled in 2018.At the same time,two reed plots in platform and water were selected for monthly sampling survey.The results showed that the difference of growth characteristics and nitrogen and phosphorus uptake between harvested and uncultivated areas was reduced by fire treatment,which indicated that the uneven growth of reed could be balanced by fire treatment.During the whole investigation period(May-September),the density,plant height and diameter of reeds were significantly different between the platform and the water.The density of reeds in the platform was significantly lower than that in the water,while theplant height and diameter were significantly higher than that in the water.The aboveground biomass of reeds was higher than that of reeds in water.There was no significant difference between May and July,but the difference increased after July.The difference reached a significant level in the three sampling periods from August to October.The total nitrogen and phosphorus contents of reed in water were significantly higher than those of platform reed,but at the beginning of growth,the nitrogen and phosphorus reserves of platform reed were higher than those of water reed because of its biomass.Then,with the rapid increase of reed density in water,the nitrogen and phosphorus reserves increased,and there was no significant difference between the two plots.Harvesting management mode is more conducive to promoting the good growth of reed,increasing net photosynthesis rate of leaves,and strengthening the removal ability of nitrogen and phosphorus in the surrounding environment of reed;fire treatment can balance the growth of reed,fire management of reed is more common in winter,but fire not only easily causes fire,but also releases a large number of harmful gases;Reed Growing in water reduces reed growth.The purifying capacity of nitrogen and phosphorus was improved obviously.It is suggested that the management of reed in Baiyangdian should be based on local conditions,take into account comprehensively and rationally,so that reed resources in Baiyangdian can be utilized scientifically in order to give full play to the ecological service function of reed. |
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