Physical and physicochemical characteristics of tomato fruits grown under different irrigation water levels and phosphorus sources and rates

Phosphorus (P) is one of the most limiting nutrients for growth and development of crops, and is important for soil fertility managements, since it affects the quality of fruits. With the hypothesis that different levels of irrigation and phosphorus fertilization interfere in the physical and physicochemical properties of tomatoes, the objective of this experiment was to verify this hypothesis and analyze the behavior of the fruits' responses. The experiment was conducted in a greenhouse at the Hydraulic and Irrigation Laboratory of the Federal Institute of Education, Science, and Technology of the State of Goias, in Rio Verde, Goias, Brazil. A randomized block design was used, with a 4x2x4 split-plot arrangement and three replications, totaling 96 experimental plots. The treatments consisted of four P2O5 rates: 25%, 50%, 100%, and 200% of the recommended rate; two P sources: monoammonium phosphate (MAP) and organo-mineral ( OM); and four IWL: 50%, 75%, 100%, and 125% of the field capacity. The fruits were evaluated for longitudinal (FLD) and transversal (FTD) diameters, potential hydrogen (pH), titratable acidity (TA), total soluble solid (TSS) contents, and TSS to TA ratio (TSS/TA). The effect of the interactions between the factors IWL and P rate, IWL and P source, and P rate and source were significant for FLD and FTD, TSS, TA, and TSS/TA. The effects of the interactions between IWL and P rate, and IWL and P source were significant for pH. The MAP source combined with the rate of 25% and IWL of 125% resulted in tomato fruits with larger FLD and FTD. The rate of 25% combined with IWL of 77% and 100% resulted in tomato fruits with higher TSS and pH. The OM source resulted in tomato fruits with higher TA when combined with IWL of 50%, and larger FLD when combined with IWL of 105% and 125%.