Avaliação agronômica e qualidade bromatológica do brócolis sob cultivos sucessivos, fontes e doses de fertilizantes especiais para fornecimento de fósforo no Cerrado

Abstract

The Organomineral fertilizers (FOs) and polymer-coated minerals (FMRs) have been presented as a new option for reducing losses due to leaching and adsorption of phosphorus (P) in weathered soils in tropical regions for longer-cycle crops, but they still need to be better evaluated for vegetables. The objective of this study was to evaluate the agronomic performance, nutritional status of the plant, and physicochemical characteristics of broccoli grown under different doses and sources of special fertilizers for P supply in Uberaba, MG. The study was conducted in a randomized block design, in subdivided plots, in which three sources of P were evaluated: 1 - conventional monoammonium phosphate (CMP); 2 - polymer-coated monoammonium phosphate (PCMP); 3 - Granulated organomineral fertilizer (GOF). Four doses were evaluated: 0 (no P application), 50 (200 kg ha-1 of P2O5), 75 (300 kg ha-1 of P2O5), and 100% (400 kg ha-1 of P2O5) of the recommended dose of P for broccoli cultivation, in three consecutive cycles, with four replicates. The nutritional status of the plant, soil fertility at harvest, number of leaves (NL), fresh mass (HFM) and dry mass of the head (HDM), and yield (YLD) of broccoli were evaluated. In the third cycle, the physical-chemical quality of the production was also evaluated. It was observed that in the first cycle, broccoli presented higher values for NL (24), HFM (1.05 kg plant-1), HDM (0.27 kg plant-1), and YLD (18.81 Mg ha-1) where PCMP was applied, which was, respectively, 5, 25, 8, and 23% higher than the GOF and 20, 25, 14, and 34% higher than the CMP; In the second cycle, the highest values for NL (23), HFM (1.85 kg plant-1), HDM (0.26 kg plant-1), and YLD (33.01 Mg ha-1) occurred where GOF was applied, which was 4, 15, 8, and 5% higher when compared to CMP and 2, 24, 4, and 14% higher when compared to PCMP, respectively; In the third cycle, the highest values for HFM (0.91 kg plant-1), HDM (0.29 kg plant-1) and YLD (22.82 Mg ha-1) occurred where GOF was applied, which was 5, 10 and 6% higher when compared to PCMP and 24, 10 and 10% higher when compared to CMP, respectively; The best agronomic performance, the highest phosphorus content in the soil and plant, and the best physical-chemical quality of broccoli occurred at the dose of 100% (400 kg ha-1 of P2O5) of the recommendation for the crop, in the three fertilizers evaluated; The moisture, ash, protein, lipid, total titratable acid, and ascorbic acid contents were not significantly affected by the fertilizers used. On the other hand, total soluble solids and pH presented the highest and lowest values in CMP, respectively; GOF provided the best agronomic performance of broccoli and the greatest residual effect on the soil in the second and third cycles compared to PCMP and and CMP.