Table 4. Correlation coefficients between grain yield and soil P fractions, enzyme activities across 2012 and 2014.

Factors	Grain yield	NaHCO3-Pia	NaHCO3-Poa	NaOH-Pi	NaOH-Po	HCl-P	Residue-P	Total-P	Dehydrogenase	β-glucosidase	Acid phosphatase	Urease
Grain yield	1	0.51**	0.26	0.49**	−0.17	−0.06	−0.09	0.38*	0.25	0.34*	0.56***	0.54***
NaHCO3-Pi		1	0.36*	0.58***	0.13	0.17	−0.09	0.60***	0.21	0.64***	0.43**	0.59***
NaHCO3-Po			1	0.59***	0.05	0.27	0.43**	0.65***	0.59***	0.60***	0.56***	0.33
NaOH-Pi				1	−0.08	0.43**	0.26	0.73***	0.39*	0.54***	0.46**	0.35*
NaOH-Po					1	−0.1	0.27	−0.06	0.11	0.07	0.02	−0.02
HCl-P						1	0.29	0.64***	0.26	0.11	0.08	−0.16
Residue-P							1	0.32	0.52**	0.11	0.2	−0.1
Total-P								1	0.47**	0.52**	0.53***	0.36*
Dehydrogenase									1	0.24	0.38*	0.08
β-glucosidase										1	0.49**	0.51**
Acid phosphatase											1	0.51**
Urease												1

^aPi: inorganic P, Po: organic P.

*Significant P < 0.05, ^**Significant P < 0.01, ***Significant P < 0.001.