APLICACIÓN DE FUENTES DE FÓSFORO AL SUELO EN DIFERENTES CORTES DE CÉSPED CULTIVADO APPLYING PHOSPHORUS SOURCES TO SOILS DURING DIFFERENT CUTS OF CULTIVATED GRASS

The objetive of this study was to evaluate the availability of phosphorus (P) in different types of soils in Principado de Asturias, Spain, by applying different P sources with a dose of 200 mg P kg -1 of soil. The grass composition, cultivated in pots, was a mixture of Agrostis tenuis cv. Highland 5 %, Poa pratense cv. Balin 5 %, Festuca rubra cv. Mystic 35 % and Lolium perenne cv. Nui 55 %. The treatments were generated with a complete factorial design of 12 types of soils, four sources of P and three dates of cutting. The sources of P were soil without fertilizer, diammonium phosphate (FD; 18 % N-46 % P 2 O 5 ), P and K complex fertilizer (RF; 20-5 of P 2 O 5 and K 2 O), and simple calcium superphosphate (SF;18 % of P 2 O 5 ), all of them with two repetitions. The grass analysis was carried out at 45, 90 and 135 d after sowing (96 experimental units). Results were analyzed with ANOVA using the SPSS 19 software, and the Tukey test (p£0.05) for the cases that presented significant differences of the primary effects and interactions. A higher production of dry matter and P absorbed in all types of soils was produced with FD. The mean relative yield of dry matter of the grass, available P in the soil, leaf P concentration and total P absorbed showed significant differences between treatments.