Study the efficiency of using phosphogypsum with organic and biological fertilization on cotton yield

Phosphogypsum (PG) is considered a by-product from the degeneration of phosphate rock (PR) in sulfuric acid. PG is widely used to improve the physico-chemical properties of soil and increase the amount of soluble nutrients in the soil. The experiment was carried out during the 2021 – 2022 seasons at Sids Research Station, Agricultural Research Center, Bani Sweif, Egypt, using the Giza 95 cultivar to evaluate the effect of PG (1.5 and 2.5 tons/fed) alone or with natural stimulants of farmyard manure (FYM) and phosphate solubilizing bacteria (PSB) on leaves' chemical constituents, growth and yield characteristics, fiber properties, and soil properties after cotton harvesting. The experiment design was a split-plot with three replicates. The main plots included calcium superphosphate and PG applications, and the sub-plots included control, FYM, and PSB applications. The results illustrated that PG application (2.5 tons/fed) recorded the significantly highest values of all studied parameters. Adding FYM achieved the significantly highest results, followed by PSB application compared to control. The interaction between PG application (2.5 ton/fed) and FYM (5 ton/fed) gave the best means on all studied parameters during the two seasons. The positive effect of PG application individually or with FYM and PSB might be related to enhancing soil properties, reducing soil pH, and producing organic and growth hormones, causing an increase in macro-and micro-nutrient uptake by plants and improving cotton plants' growth and development