Physiological responses of tomato plants subjected to various combinations of irrigation levels with mineral and organomineral sources of phosphorus

The objective of this study was to evaluate physiological characteristics and productivity of tomato plants, in response to different irrigation depths associated with doses and sources of mineral and organomineral phosphorus (P). This research is justified by the importance of cultivation with greater water use efficiency, as well as the environmental importance of the use of organomineral fertilizers, especially aiming nutrient recycling. The experiment was conducted in a greenhouse with tomato plants in plastic pots filled with 23 L of soil. The treatments consisted of four doses of phosphorus pentoxide (P 2 O 5 ) (25%, 50%, 100% and 200% of the recommended dose); two P sources (monoammonium phosphate—MAP and organomineral phosphate—OM), and four irrigation depths [50%, 75%, 100% and 125% of field capacity (FC)]. The physiological characteristics of the plants at different times after planting and the fruit yield at the end of the crop cycle were evaluated. The P dose of 25% and application of the MAP source provided higher absolute and relative growth rate of plant in height, at 66 and 96 days after planting (DAP). For the OM source, the P doses of 118% and 136% provide, respectively, higher chlorophyll b and total chlorophyll indexes of plants at 51 DAP. The 125% depth provided the highest water use efficiency (WUE) for the recommended dose (100%) of P, while the 50% depth provided the highest WUE for the tomato plants by adding 50% of the recommended P dose. The highest fruit yield was observed at the dose of 100% P, regardless of the source, associated with an irrigation depth of 125% of field capacity.