福建省马尾松和杉木针叶中7种营养元素含量特征

为了解福建省马尾松和杉木人工林养分需求特征,选取25个马尾松(Pinus massoniana)林和31个杉木(Cunninghamia lanceolata)林,测定了针叶中7种主要营养元素(C、N、P、S、K、Ca、Mg)含量。结果表明,马尾松针叶K、Ca、Mg含量显著低于杉木,分别是杉木的68%、14%、50%,表明杉木对矿质养分尤其Ca的需求远高于马尾松,提示马尾松比杉木更能适应矿质养分尤其Ca较贫瘠的立地。两树种针叶C、N、P、S含量及其化学计量比均表现出相似的内稳态特征,而Ca、Mg、K含量及其化学计量比的变异大,表明这3种矿质元素受立地条件的影响较大。两树种对N、P、K需求表现为协同正相关关系,N与Ca含量则为负相关关系,暗示持续N沉降或营林实践中长期施N肥可能抑制Ca的吸收。

Characteristics of Seven Nutrient Elements in Needles of Pinus massoniana and Cunninghamia lanceolata Forests in Fujian Province

In order to understand the characteristics of nutrient requirement in Pinus massoniana and Cunninghamia lanceolata forests in Fujian, China, the concentrations of seven nutrient elements, including C, N, P, S, K, Ca, and Mg, in needles collected from 25 P. massoniana plots and 31 C. lanceolata plots were determined. The results showed that the concentrations of needle K, Ca and Mg in P. massoniana were only 68%, 14% and 50% of those in C. lanceolata, respectively, indicating the demand for mineral elements, particular Ca, were markedly higher by C. lanceolata than by P. massoniana, with an important implication that P. massoniana has much higher potential adaptability to poor nutrients, particular Ca impoverished sites than C. lanceolata. Both tree species showed similar homeostasis either in concentrations of C, N, P and S or in their stoichiometric ratios. In contrast, large variabilities of Ca, Mg and K concentrations and their stoichiometric ratios were observed in both species, revealing the large influence of site condition on these elements. Both species showed positive synergy relationships for the demands of N, P and K, while negative correlations were observed between N and Ca. This suggests that atmospheric N deposition or long-term application of N fertilizers through forest management may cause the inhibition of Ca uptake.