ABSTRACT
In many tropical ecosystems, phosphorus (P) is a scarce limiting nutrient. Yet Yao et al. (2018) found that transformation of nitrogenous compounds and the assimilation of sulfur and proteins for the degradation of phospholipids and phosphorus-containing nucleic acids, as well as the decomposition of labile carbon and nitrogen, were highly represented in phosphorus-deficient soils, while microbial communities in phosphorus-rich soil had a gene abundance for the degradation of aromatic compounds, transformation of nitrogenous compounds, and the assimilation of sulfur. Furthermore, sugarcane regrowth is improved in P-efficient varieties under P-deficiency conditions (Zambrosi et al. (2015), a finding of practical relevance as such ability might benefit the productivity and the longevity of sugarcane ratoons in low-P tropical soils (Zambrosi et al. 2017). Thus Yao et al. (2018) concluded that their results demonstrate the adaptive allocation of genes and proteins where there are shifting nutrient constraints. Also, without attributing causation, Zambrosi et al. (2015) correlated the typically larger leaf area of some sugarcane varieties with efficient phosphorus uptake under low-phosphorus soil conditions. Hence “such finding might be explained by the positive effect of improved leaf P concentration on leaf area and net CO2 assimilation, which in turn contributed to sustaining improved plant performance under a low P supply” (Zambrosi et al. 2015). However, despite such demonstrated P-efficiencies, phosphorus remains limiting for crop yield on >30% of the world’s arable land and, by some estimates, world resources of inexpensive P may be depleted by 2050 (Vance et al. 2003; FAO 2004).
