Nutritional value and foliar fertilization in soybean

Soybean is a member of pulses and probably the most valuable crop in world. Fertilization is one of the main economic and health-promoting factors in crop cultivation. Foliar application during the flowering stage using 4 phosphorus (P) doses (4, 6, 8 and 10 kg ha-1) as experiment-1 and 4 sulphur (S) doses (5, 10, 15 and 20 kg ha-1) as experiment-2 except control in the soybean variety Nova was performed in Konya, Turkey, in two years (2013 and 2014), in a randomized block design with 3 replications. The investigated nutrition parameters were protein (316.5-368.3 g kg-1), mineral components (in mg kg-1): P (6200-7350), K (8141-8302), Mg (951-1267), Ca (1083-1419), Fe (61.20-97.90), Cu (22.10-35.60), Zn (62.30-85.30), Mn (3.600-18.90) and fatty acids (in g kg-1): myristic (0.76-0.81), palmitic (109.3-115.1), stearic (41.32-50.12), oleic (229.4-266.7), linoleic (487.4-520.3), linolenic (70.58-85.32), arachidic (3.77-4.32), gadoleic (2.49-4.05), eicosadienoic (0.43-0.63), eicosatrienoic (3.76-4.11), lignoceric (1.33-1.46), nervonic (0.13-0.58) and docohexaenoic (0.24-0.68) acid. Statistical analysis showed significant levels for Mn (P applied at 5% level), myristic acid (S at 1% level), palmitic (P at 1% level), stearic (P at 1% level), linolenic (P at 1% level), nervonic (P at 5% level) and for docohexaenoic acid (P and S at 5% level). In general, the content of protein, Mg, Mn, palmitic, linoleic and linolenic acids showed an increasing tendency with the increased doses of phosphorus. Additionally, protein, Cu, Zn, palmitic, linolenic, gadoleic, eicosadienoic and docohexaenoic acids showed an increasing tendency with the increased doses of sulphur. Consequently, the response of soybean plants to foliar application of S and especially P during the flowering period entailed significant changes, especially in protein and essential fatty acids. The results can be used in nutritional medicine and by farmers, food companies, breeders, etc.