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Phosphorus and Nitrogen Fertilization Effect on Phosphorus Uptake and Phosphatase Activity in Ryegrass and Tall Fescue Grown in a Chilean Andisol

Research output: Contribution to Journal/MagazineJournal articlepeer-review

<mark>Journal publication date</mark>05/2011
<mark>Journal</mark>Eurasian Soil Science
Issue number5
Number of pages7
Pages (from-to)245-251
Publication StatusPublished
<mark>Original language</mark>English


A series of short-term experiments were carried out to assess the effect of phosphorus (P) and nitrogen (ammonium [NH(4) (+)-N] or nitrate [NO(3)(-)-N]) fertilization on P uptake and phosphatase activity in ryegrass and tall fescue cultivated under greenhouse conditions. Ryegrass or tall fescue plants were grown in an acidic Andisol in the presence or absence of P and increasing doses of NO(3)(-)-N or NH(4)(+)-N fertilizers. At the end of the experiment, soil phosphatase activity (P-ase(Rhiz)), pH, and Olsen-P were determined in the rhizosphere soil. Plant biomass, P uptake, and root surface phosphatase (P-ase(Root)) were also assayed for both plant species. Furthermore, soil incubation experiments at increasing doses of P, NO(3)(-)-N, or NH(4)(+)-N were performed to evaluate the fertilizer effect on soil phosphatase activity (P-ase(Bulk)) and microbial biomass carbon in the bulk soil. In the absence of plants, P-ase(Bulk) was inhibited and microbial biomass carbon was raised at increasing P supply levels. In the greenhouse experiments, P uptake by tall fescue was about 67% higher than that of ryegrass at low soil P availability, which suggests that tall fescue was less sensitive to P deficiency than ryegrass. For both plant species, P-ase(Rhiz) did not vary as a consequence of P addition. On the other hand, fertilization with the highest NH(4)(+)-N dose strongly decreased soil pH and shoot P content, as well as it increased P-ase(Root) activity. This fact denotes that P-ase(Root) behaved as a strategic response parameter to P stress with insufficient impact on plant P nutrition in both plant species.