Differential responses and mechanistic controls of soil phosphorus transformation in Eucalyptus plantations with N fertilization and introduced N₂‐fixing tree species

Abstract

Summary Introducing N2‐fixing tree species into Eucalyptus plantations could replace nitrogen (N) fertilization to maintain high levels of N consumption and productivity. However, N enrichment may exacerbate phosphorus (P) limitation as Eucalyptus robusta Smith is extensively planted in P‐poor tropical and subtropical soils. We conducted a field experiment in a pure plantation of Eucalyptus urophylla × grandis to investigate the impacts of N fertilization and introduced an N2‐fixing tree of Dalbergia odorifera T. Chen on soil P transformation. Nitrogen fertilization significantly enhanced soil occluded P pool and reduced the other P pools due to acidification‐induced pH‐sensitive geochemical processes, lowering Eucalyptus leaf P concentration with higher N : P ratio. By contrast, introduced N2‐fixing tree species did not change soil pH, labile inorganic P pool, and Eucalyptus leaf N : P ratio, even enhanced organic P pools and reduced occluded P pool probably due to altering microbial community composition particularly stimulating arbuscular mycorrhiza fungal abundance. Our results revealed differential responses and mechanistic controls of soil P transformation in Eucalyptus plantations with N fertilization and introduced N2‐fixing tree species. The dissolution of occluded P pool along with organic P accumulation observed in the mixed plantations may represent a promising future to better manage soil P availability.

Differential Responses of Soil Phosphorus Fractions to Nitrogen and Phosphorus Fertilization: A Global Meta‐Analysis

“…By contrast, N addition decreased soil available Pi in both tropical and subtropical areas. In agreement, several new studies also reported that acid addition-induced pH reduction increased the occluded P fractions and decreased the labile P fraction in tropical soil (Hu et al, 2022;Yao et al, 2023). The likely explanation for this pattern is that soil acidification accelerates the solubility of minerals and also results in enrichment of highly charged exchangeable cations in strongly weathered tropical soils (X. M. Wang et al, 2013), thus enhancing the binding of dissolved Pi to their surfaces.…”

Effects of Different Altitudes on Castanopsis hystrix, the Top Community-Building Species in Southern Subtropical China: Rhizospheric Soil Chemical Properties and Soil Microbiota

“…The study area was situated along the southern edge of the south subtropical zone (Figure 1), bordering the northern tropics, and is characterized by a south subtropical monsoon climate [32]. It spans from 21 C as the warmest month.…”

“…(Figure 1), bordering the northern tropics, and is characterized by a south subtropical monsoon climate [32]. It spans from 21°57′47″ N to 22°19′27″ N and from 106°39′50″ E to 106°59′30″ E. The average annual temperature is 21.5 °C, with January averaging 13.5 °C as the coldest month and July averaging 27.6 °C as the warmest month.…”

Structural Equation Modeling of Phosphorus Transformations in Soils of Larix principis-rupprechtii Mayr. Plantations

“…A detailed investigation of P dynamics and bioavailability requires the separation and identification of different forms of P in soils [12]. Sequential fractionation is one of the most commonly used methods to study soil P dynamics owing to its advantages of low operating cost, small amount of samples needed, and practicality [13,14]. The P fractionation procedure of Hedley et al [15] and its modification by Tiessen and Moir [16] are the most commonly used [17][18][19].…”