• 研究报告 •

### 长江上游马尾松人工林采伐林窗对土壤磷含量的初期影响

1. （四川农业大学生态林业研究所， 四川生态林业工程重点实验室， 成都 611130）
• 出版日期:2014-03-10 发布日期:2014-03-10

### Early influence of forest gap harvesting on soil phosphorus in Pinus massoniana plantation in a hilly area of the reaches of Yangtze River.

OU Jiang, LIU Yang, ZHANG Jian**, ZHANG Jie, CUI Ning-jie, DENG Chang-chun, JI Tuo-wei, HE Run-lian

1. (Key Laboratory of Ecological Forestry Engineering of Sichuan Province, Institute of Ecology & Forestry, Sichuan Agricultural University, Chengdu 611130, China)
• Online:2014-03-10 Published:2014-03-10

Abstract: The seasonal variations of soil microbial biomass phosphorus (MBP), available phosphorus (AP) and total phosphorus (TP) were observed in seven size gaps (G1: 100 m2, G2: 225 m2, G3: 400 m2, G4: 625 m2, G5: 900 m2, G6: 1225 m2, G7: 1600 m2) of a masson pine plantation in a hilly area of the upper reaches of Yangtze River. The results showed that the soil MBP in the forest gaps was most sensitive to cutting disturbance, followed by soil AP, while TP was relatively stable. The effects of gap size were significant on soil MBP and AP, but not on soil TP. The center of forest gap with a size of 625-900 m2 was more conducive to increase soil MBP, the center of larger gap (900-1600 m2) had a higher level of soil AP as well as the edge of medium-sized gap (225-625 m2), and the center of forest gap (625 m2) had a high level of soil TP. MBP and AP had significant changes in different periods of the growing season, but TP had no significant changes. Soil MBP of the centers of all gaps and the edges of gaps less than 625 m2 was lower in the early period, but that of other areas was higher in early and lower in middle of growing season. Soil AP in the gap center was higher in the middle and lower in the early of the growing season, while lower in the early stage of gap edge. In addition, the interaction of gap size and seasonal variation had significant impacts on soil MBP. The location within forest gap had no significant influence on MBP, AP and TP, but the soil AP and TP of all gaps in the middle and late growing season were higher than in the understory soil, while the soil MBP of large-sized gap was only lower in the middle growing season. It is suggested that soil phosphorus was improved in a certain degree after the formation of forest gaps. Correlation analyses showed that soil MBP was significantly positively correlated with TP, but significantly negatively correlated with soil temperature, and soil MBP and TP were significantly positively correlated with soil water content. Therefore, soil temperature and moisture were major environmental factors affecting soil phosphorus in early formation of forest gaps.