Table 1.

Design and results of Box–Benhnken experiment.

Run	Concentration of Sucrose	Concentrations of Ammonium Sulfate and Soybean Residue	Concentration of Tricalcium Phosphate	Concentration of Inorganic Salt	Phosphate-Solubilizing Capacity (mg/L)
	0	−1	0	1	85.47
2	0	0	1	1	65.77
3	0	1	1	0	65.99
4	1	0	−1	0	79.00
5	0	1	−1	0	96.67
6	1	−1	0	0	42.09
7	0	0	−1	−1	90.00
8	0	−1	0	−1	50.95
9	0	0	0	0	120.67
10	−1	0	0	1	92.16
11	1	0	0	−1	50.44
12	1	0	0	1	93.00
13	0	−1	−1	0	56.57
14	1	1	0	0	68.76
15	−1	−1	0	0	76.91
16	0	−1	1	0	46.42
17	0	1	0	1	98.05
18	0	0	1	−1	60.09
19	−1	0	1	0	53.62
20	0	0	0	0	123.72
21	0	0	0	0	116.12
22	−1	0	0	−1	90.93
23	1	0	1	0	42.17
24	0	0	−1	1	101.72
25	0	1	0	−1	96.00
26	0	0	0	0	108.23
27	−1	1	0	0	100.98
28	−1	0	−1	0	102.13
29	0	0	0	0	115.55