杉木人工林林木养分的季节变化及养分间的相互关系

作者于1988年在枫树山林场浮东分场林龄和立地条件不同的杉木人工林中采集针叶样品分析 N、P、K、Ca、Mg和S浓度以探寻杉木人工林的营养特性、养分的季节变化动态及不同养分之间的相互作用关系。结果表明,幼、壮、中龄林不同生育期养分的季节变化规律相似。针叶N、P、K、Mg和S浓度均为生长初期最低或较低,幼林针叶全氮及幼、壮、中龄林针叶全磷、全钾和全硫均在第一个生长高峰期(6月中旬)达到最大值,壮、中龄杉木针叶全氮及幼、壮、中龄杉木针叶全镁则在第二个生长高峰期(9月中旬)达到最大值。速生期杉木针叶全钙较低,尤其是第一个生长高峰期,初期和末期较高或最高。杉木植株氮、磷代谢之间存在明显的正相关关系。氮、硫代谢相互促进。钾、钙、镁营养之间存在显著的颉颃作用。

SEASONAL CHANGES OF NUTRIENT CONCENTRATIONS AND NUTRIENT INTERACTIONS IN NEEDLES OF CHINESE FIR PLANTATIONS

Current or 1 - year - old needles from dominant , average and depressed trees in different Chinese fir stands at Fudong Branch of Fengshushan Forest Station were sampled in different seasons in 1988, and nutrient concentrations of N, P, K, Ca, Mg and S in needles were analyzed to reveal the nutritional characteristics, nutrient dynamics and the interaction between various nutrients in the Chinese fir plantations. The nutritional status in the Chinese fir plantations was closely related to stand age and site quality. There were similar seasonal changes of nutrient concentrations in 5-, 10-, and 20-year-old Chinese-fir stands. Total N, P, K, and Mg were lowest and total S was lower during bud flush; total N in needles of 5-year-old stands and total P, K, and S in needles of 5-, 10-, and 20-year-old stands were highest during the first fast growing season (mid-June) total N in needles of 10-and 20-year-old stands and total Mg in needles of 5-, 10-, and 20-year-old stands were highest during the second fast growing season (mid-September). Total Ca in needles was lower during fast growing seasons, especially the first fast growing season, and higher or highest during bud flush or pre-dor-mancy. There was a significantly positive interaction between N and P nutrition in Chinese fir plantations and a positive relationship between N and S metabolism but significant antagonism between K, Ca and Mg. On the windward slope, N and P nutrition in the Chinese fir plantations were depressed, total Ca and total Mg in needles declined but K nutrition was strengthened.