Trocas gasosas e teores foliares de NPK em meloeiro adubado com biofertilizantes

Abstract

The aim of this study was the evaluation of biofertilizing with different biofertilizer types applied in different doses. We tested gas exchanges and leaf NPK contents on the melon plant (Cucumis melo L.). The experiment was conducted at the experimental area of the UFC (Universidade Federak do Ceará), in Fortaleza, in the period from September (2011) to December (2011). The experimental design was that of randomized blocks in a factorial 2 × 4 + (2) arrangement, corresponding to two types of liquid biofertilizer (mixed aerobically fermented biofertilizer and simple anaerobically fermented bovine biofertilizer) and four fertilizer doses (0.5, 1.0 , 1.5 and 2.0 L plant -1 week-1), with two additional treatments (control and recommended mineral fertilization). We analyzed the following variables: transpiration, stomatal conductance, photosynthesis and leaf Nitrogen (N) content, leaf phosphorus (P) content and leaf potassium (K) content. Plants biofertilized with simple bovine biofertilizer showed higher photosynthetic and transpiration rates, while the mixed biofertilizer was more efficient in terms of stomatal conductance. The simple bovine biofertilizer provided higher leaf phosphorus contents, while mixed biofertilizer provided higher leaf nitrogen and leaf potassium contents, when compared to control and to mineral fertilization. At the end of the production cycle, the plants fertilized with mixed biofertilizer and simple were supplied in N and P, and deficient in K.