Phosphorus and Biofertilizer Application Effects on Growth Parameters, Yield and Chemical Constituents of Broccoli

Broccoli is a popular vegetable throughout the world and contains important nutritional features. This study was conducted to evaluate the effect the fertilization with different phosphorus sources (i.e., soil application of rock phosphate (RP) at 428 kg ha⁻¹, calcium superphosphate (CSP) at 670 kg ha⁻¹, phosphoric acid (PA) at 126 L ha⁻¹ and monoammonium phosphate (MAP) at 334 kg ha⁻¹) combined with biofertilizers (i.e., inoculation with phosphorin or mycorrhiza) on plant growth aspects, antioxidants enzyme activity, chemical constituents, yield and quality of broccoli leaves and heads (<i>Brassica oleracea</i> var. <i>italica</i> Plenck). The experiment was performed according to the randomized complete block design with three replications (<i>n</i> = 3), for two growing seasons (2018–2019) at the experimental farm of Benha University, Egypt. The obtained results showed that the highest values of plant height, leaf area, fresh and dry weight of leaves/plant, head weight and diameter, and the highest yield of heads ha⁻¹ were recorded in plants that received MAP fertilizer and were inoculated with mycorrhiza. On the other hand, the highest value of head length, total carbohydrate and total soluble solids (TSS) content were observed in plants fertilized with PA and inoculated with mycorrhiza. The highest leaf nitrogen % and head ascorbic acid content, as well as the lowest head total phenol content were recorded in plants supplemented with MAP fertilizer and inoculated with mycorrhiza. Moreover, broccoli plants fertilized with PA and inoculated with mycorrhiza showed promising results in terms of phosphorus, potassium and total carbohydrate content, antioxidant activity and dehydrogenase activity. In conclusion, phosphorus may affect plant growth, yield and chemical parameters in broccoli plants depending on the fertilizer source, while inoculation with mycorrhiza may also have a beneficial impact on these parameters.