Data from: Tropical tree growth is correlated with soil phosphorus, potassium, and calcium, though not for legumes

Tropical forest productivity is widely assumed to be limited by soil
phosphorus (P), but biogeochemical processes that deplete P also could
deplete base cations, suggesting multiple resource limitation. Limitation
by several resources could arise from species and functional diversity,
and variation among groups in resource requirements, including
ecophysiological strategies that minimize P limitation. We hypothesized
that tree growth is positively related to soil base cation and P
availability and negatively related to local competition; Fabaceae growth
is weakly correlated with soil resources if fixed N is used indirectly to
acquire other resources; growth of species with low wood density is more
strongly related to soil resource availability than species with high wood
density. Diameter growth and soil resource availability were measured in
five mapped stands situated across natural soil resource gradients in
lowland wet tropical forest (La Selva Biological Station, Costa Rica).
Soil resource availability, and associated uncertainty, was estimated for
each tree using a Bayesian multivariate spatial regression model, with
individual tree growth a function of diameter, local neighborhood, and
soil resources. Separately, site-level mean tree growth and resource
availability were modeled using linear regression. Individual diameter
growth and site mean basal area increment correlated with soil base
cations and P, but rarely with N; individual growth correlated negatively
with neighborhood index for only three species. Growth of Fabaceae was
unrelated to soil resources both at individual and site levels. When
species were categorized by wood density, growth was related to soil P or
base cation availability, with strongest correlation between
lowest-density species and soil P. Several resources may limit tropical
forest productivity because tree growth was similarly correlated with soil
P and base cations, but functional groups responded differently.
Negligible growth relationships with soil resources in Fabaceae suggest
that N fixation may alleviate mineral nutrient limitations. Correlations
of soil P with growth of low wood density species and base cations with
species of higher density suggests variation in resource demands among
functional groups. Thus, tropical tree growth may be limited by base
cations and/or P, with degree and type of resource limitation dependent on
functional or taxonomic group.

热带森林生产力普遍被认为受土壤磷（P）限制，但耗竭磷的生物地球化学过程同时也会耗竭盐基阳离子（base cations），这提示存在多种资源共同限制的情况。多种资源的限制作用可能源于物种与功能多样性，以及不同类群间资源需求的差异，包括可弱化磷限制的生态生理策略。本研究提出如下假说：树木生长与土壤盐基阳离子及磷的有效性呈正相关，与局部竞争呈负相关；若固氮可间接用于获取其他资源，则豆科（Fabaceae）植物的生长与土壤资源的相关性较弱；木材密度较低的物种，其生长与土壤资源有效性的关联程度强于木材密度较高的物种。研究在哥斯达黎加的拉塞尔瓦生物站低地湿润热带森林中，依托自然土壤资源梯度设置了5个固定样地，测定了树木径生长与土壤资源有效性。研究采用贝叶斯多元空间回归模型（Bayesian multivariate spatial regression model）估算了每棵树所在位置的土壤资源有效性及其相关不确定性，以个体树木生长作为胸径、局部邻域竞争与土壤资源的函数；此外还通过线性回归分别建模了样地水平的平均树木生长与资源有效性。个体径生长与样地平均断面积增量均与土壤盐基阳离子及磷呈显著相关，但极少与氮相关；仅3个物种的个体生长与邻域竞争指数呈负相关。豆科植物的生长无论在个体水平还是样地水平均与土壤资源无显著关联。当按木材密度对物种进行分类后，树木生长与土壤磷或盐基阳离子有效性相关，其中木材密度最低的物种与土壤磷的相关性最强。由于树木生长与土壤磷和盐基阳离子均呈相似的相关性，热带森林生产力可能受多种资源共同限制，但不同功能类群的响应存在差异。豆科植物与土壤资源的生长关联微弱，提示固氮作用可缓解矿质养分限制。土壤磷与低木材密度物种生长的相关性、盐基阳离子与较高木材密度物种生长的相关性，则表明不同功能类群的资源需求存在变异。综上，热带树木生长可能受盐基阳离子和/或磷限制，资源限制的程度与类型取决于功能类群或分类学类群。