大连生态园区春季氮含量变化规律的研究

采用凯氏定氮法测定了前期(4月17日和5月1日)和后期(5月15日和5月29日)4次在大连生态园区采集的植物和土壤样本的含氮量。结果表明:(1)草本植物的平均含氮量最高为33.8g·kg-1,比木本植物高了6.21%,是土壤的5.2倍;木本植物的平均含氮量是土壤的4.9倍;植物平均含氮量为32.8g·kg-1,是土壤的5.0倍;(2)在草本植物中,节节草的平均含氮量为37.4g·kg-1,比山羊草高了19.25%。在木本植物中,槐树的平均含氮量为38.8g·kg-1,比松树高了33.76%;槐树土壤的平均含氮量为7.1g·kg-1,比松树土壤高了18.31%;(3)草本植物的根和茎叶的平均含氮量在前期和后期保持一定水平。在木本植物中,槐树和松树前期的平均含氮量分别为42.8,33.1g·kg-1,比后期分别高了15.42%和44.71%。其中,槐树和松树的根和茎平均含氮量前期分别为63.0,22.5g·kg-1和47.0,29.5g·kg-1,比后期高了30.95%、14.22%和32.98%、91.53%;槐树前期未长叶,后期叶的含氮量为45.8g·kg-1,松树叶的含氮量前期为22.8g·kg-1,比后期高了7.9%。槐树和松树根际土壤含氮量,槐树后期8.3g·kg-1比前期高了27.7%,松树前期6.2g·kg-1比后期高了12.9%;(4)槐树和松树的平均含氮量与其根际土壤的比值分别是前期为7.1和5.3,后期为4.4和3.4。确定生态园区主要组份的含氮量,对调控环境成分的氮水平,建设生态园区具有十分重要的意义。

Research on Changes of Nitrogen Concentrations in Plants and Soil at Dalian Ecological Park in Spring

The nitrogen contents of plant and soil samples collected at the Dalian Ecological Park on April 17, May 1, 15 and 29 were determined by the Kjeldahl. The results were as follows:(1) the average nitrogen content in the herbs was the highest in plants and soils collected ,it was 33.8 g·kg-1, and increased 6.21% than that in woody plants , it was 5.2 times than that of soil. (2) In the herbs, the average nitrogen content in equisetum ramosissimums was 37.4 g·kg-1, it increased 19.25% than that in aegilops. In the woody plants, the average nitrogen content in acacia trees was 38.8 g·kg-1, it inproved 33.76% than that in pine trees; the average nitrogen content in the soils of acacia tree root nearly was 7.1 g·kg-1, and 18.31% higher than it in the soils of pine tree root nearly. (3) The average nitrogen contents in the herbs’ roots, stems and leaves in earlier and later of spring maintained a certain level .In the herbs , the average nitrogen contents in acacia trees and pine trees in the earlier period were 42.8,33.1 g·kg-1, 15.42% and 44.71% higher than them in the later period ,respectively. Specifically, the average nitrogen contents in the roots and stems of acacia trees and pine trees in the earlier period were 63.0,22.5 ,47.0 ,29.5 g·kg-1 ,increased 30.95%,14.22%,32.98% and 91.53% than them in the later period, respectively ;as for acacia trees ,in the earlier period they did not grow out the leaves and in the later the average nitrogen content in their leaves was 45.8 g·kg-1 ; the average nitrogen contents in pine trees’ leaves in the earlier period was 22.8 g·kg-1, increased 7.9% than that in the later period . As for the average nitrogen contents in the soils of acacia and pine tree root nearly, acacia trees in the later period contained 8.3 g·kg-1, increased 27.7% than that in the earlier period , however , pine trees in the earlier period contained 6.2 g·kg-1 ,increased 12.9% than that in the earlier period. (4) The ratios of acacia and pine trees and their rhizosphere soils in the average nitrogen contents were 7.1 and 5.3 in the earlier period, 4.4 and 3.4 in the later period, respectively. It was certain that the nitrogen concentrations in the primary tissues of the Ecological Park were great significance to the environmental nitrogen and construction of the Dalian Ecological Park.