IMPACT OF FOLIAR AND SOIL FERTILIZATION ON PRODUCTIVITY AND QUALITY OF SOME SOYBEAN CULTIVARS UNDER CALCAREOUS SOIL CONDITIONS

A field experiment was conducted at Nubaria Agricultural Research Station Farm,  Alexandria, Egypt, during 2015 and 2016 summer seasons  to evaluate the efficiency of three fertilization treatments (i.e. T₁: recommended dose of soil  fertilizers of 48 kg N /ha + 72 kg P₂O₅/ha and 57.6 kg K₂O/ha, T₂: 50% of the previous recommended dose of 24 kg N/ha +36 kg P₂O₅/ha and 28.8 kg K₂O/ha with foliar application of  phosphoric acid (0.025%) and potassin (1.8 ppm). T₃: foliar application of phosphoric acid (0.025%) and potassin (1.8 ppm) only) on growth, productivity and quality of three soybean cultivars, Giza 21, Giza 22 and Giza 111. The results revealed significant differences among studied cultivars in crop growth rate, chlorophyll content, plant height, number of branches/plant, number of pods/plant, 100-seed weight, seed yield/ha, oil and protein yields/ha, Seed oil (%), seed protein content, seed phosphorus (%), seed potassium (%), straw nitrogen (%), straw phosphorus (%) and straw potassium (%) in both seasons and their combined analysis with superiority of Giza 111 in all studied traits followed by Giza 21, while Giza 22 recorded the lowest values for such traits except  plant height, where Giza 22 cv gave the tallest plants  (115.1 cm). Differences due to fertilization treatments were significant   for all   studied traits, where   T₂ treatment (50% of the recommended dose of N, P and K + phosphoric acid and potassin) outperformed the other treatments followed by T₁ treatment, while the T₃ treatment gave the lowest values. The interaction between cultivars and fertilization treatments significantly influenced on No. of branches/plant, chlorophyll content and seed oil (%) in the first season and seed phosphor (%) in both seasons. In general, the highest value of seed yield/ha was obtained from Giza 111 cultivar meanwhile, the treatment of 50% recommended dose of N, P and K + phosphoric acid and potassin gave also the best seed yield/ha. Seed yield (ton/ha), was positively and significantly correlation with each of number of branches/plant (0.834*), number of pods/plant (0.956**), 100- seed weight (0.824*), oil yield (ton /ha) (0.954**), protein yield (ton/ha) (0.988**) and cholorophyll content (0.965**).