Greenhouse evaluation of struvite and sludges from municipal wastewater treatment works as phosphorus sources for plants.
Sewage sludge obtained by a conventional aerobic activated sludge process (CSS), P-rich sewage sludge from an enhanced biological P removal process (PRS), and struvite (MgNH 4PO 4 x 6H 2O) recovered from an anaerobic digester supernatant using a low-grade MgO byproduct from the calcination of natural magnesite as a Mg source (STR) were evaluated as P sources for plant growth. For this purpose, a greenhouse pot experiment was conducted using a P-deficient loamy sand soil and perennial ryegrass ( Lolium perenne L.) as the test crop. The P sources were applied at rates equivalent to 0, 9, 17, 26, 34, and 44 mg/kg P. Single superphosphate (SUP) was used as reference for comparison with the other P sources. The results obtained indicated that STR was as effective as SUP in increasing the dry matter yield and supplying P to ryegrass. Compared to SUP and STR, PRS and especially CSS exhibited less agronomic effectiveness as P sources, which may be attributed, at least partially, to greater soil P fixation because of the larger amount of Fe incorporated with these materials.
Plaza
César
C
Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Científicas, Serrano 115 dpdo., 28006 Madrid, Spain. c.plaza@ccma.csic.es
Sanz
Rafael
R
Clemente
Cristina
C
Fernández
José M
JM
González
Ricardo
R
Polo
Alfredo
A
Colmenarejo
Manuel F
MF
D000383:Agriculture / Q000379:methods*; D005308:Fertilizers; D008129:Lolium / Q000254:growth & development* / Q000378:metabolism; D017616:Magnesium Compounds / Q000008:administration & dosage*; D010710:Phosphates / Q000008:administration & dosage*; D010758:Phosphorus / Q000008:administration & dosage*; D012722:Sewage / Q000737:chemistry*; D000069877:Struvite
D005308:Fertilizers; D017616:Magnesium Compounds; D010710:Phosphates; D012722:Sewage; D010758:Phosphorus; D000069877:Struvite