The objective of the present study was to assess the development of guava tree cuttings in response to different doses and modes of application of phosphate fertilizer. The guava tree cuttings were transplanted in twin sets of pots (18 x 28 cm plastic bags) containing 2.8 dm³ of the subsoil of a Argisol (Ultisol, Soil Taxonomy; P resin = 1 mg dm-3) in such a way that half of the root system would remain in each pot. A 2x3x2 + 1 factorial arrangement (check, without phosphate) in 5 randomized blocks was used. Doses of 70, 140 and 280 mg of Pdm-3 of soil in form of triple superphosphate were applied in two different manners to the soil (distributed throughout the soil volume or placed only at a depth of 1/3) and in the roots (by dividing the dose equally between the two pots of the set or by applying the total dose to a single pot). The greatest accumulation of P and the greatest production of dry matter was observed 100 days after transplant in the plants that received phosphate fertilizer. The guava cuttings responded positively to phosphate fertilization, with the dose of about 100 mg of Pdm-3 of soil being sufficient for good plant development. Doses above of 200 mg Pdm-3 promoted a reduction of plant growth. Making phosphorus available to half or to the entire root system of the guava plant did not affect the supply of this nutrient to the cuttings or their development. The application of phosphate fertilizer distributed throughout the soil volume in the pot favored a better development of the root system and a lower development of the aerial part of the guava cuttings compared to application of the fertilizer localized at a depth of 1/3.
Psidium guajava; cuttings; fruit tree; phosphorus placement; split-root
