Effects of calcium on agronomic parameters and nutritional quality of soybean [Glycine max (L.) Merrill] grown in Ogbomoso, Nigeria

Soybean (Glycine max L.) is a good source of protein and oil for man and livestock usage. The need to provide more quality soybean requires more study; hence, this field experiment was carried out to determine the effect of calcium application on performance and nutritional quality of soybean. The treatment were five levels of calcium application (0, 15, 30, 45 and 60 kg Ca/ha) using gypsum as source and three cultivars of soybean (V1-TGX 1835–10E, V2-TGX 1987–62F and V3-TGX 1910–42F) resulting in a 15 treatment combination replicated three times and arranged in factorial experiment fixed into randomized complete block design (RCBD). The total rainfall and average temperature were 1093.2 mm and 26.4°C within the period under study. Growth responses of soybean to treatments were recorded starting from three weeks after planting at one-week interval. Yield parameters were also taken and data collected were subjected to the analysis of variance and means were separated using least significant difference at 5% probability level. The results showed that calcium application at 0 kg Ca/ha (control) produced the tallest plant (35.57 cm) and highest number of leaves (19.94), and seed weight (1, 694.20 kg/ha). Application 45 kg Ca/ha produced the highest mean pod weight (2, 919.20 kg/ha). TGX 1910–42F produced the highest mean plant height and number of leaves (36.21 cm and 20.92, respectively), while TGX 1835–10E had the highest mean pod and seed weight (3, 187.50 and 1, 770.30 kg/ha, respectively). Also, the highest protein percentage (45.6) was obtained from TGX 1835–10E treated with 60 kg Ca/ha. This experiment showed that application of calcium might not be needed for pod and seed production in the trial area but was required for better nutritional quality.