Artificial Neural Networks for Estimating Soil Water Retention Curve Using Fitted and Measured Data

Table 3

Sensitivity analysis of developed ANNs by substituting step by step each input parameter by its mean value.

ANN 1
(−cm)	Model’s; RMSE	Bulk density			Particle density		Porosity		Sand		Silt		Clay
		RMSE	Var (%)		RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)
0	0.064	0.089	39.478		0.065	1.242	0.075	16.638	0.064	0.052	0.064	−0.523	0.069	7.5083
10	0.057	0.084	46.749		0.058	1.278	0.065	13.704	0.062	8.581	0.055	−3.819	0.058	1.718
20	0.056	0.079	40.550		0.056	0.859	0.065	16.952	0.067	12.082	0.056	−0.784	0.059	5.105
30	0.051	0.068	32.408		0.051	0.038	0.061	17.870	0.064	25.153	0.051	−0.019	0.056	8.416
50	0.049	0.064	27.561		0.050	−0.012	0.054	8.511	0.069	37.830	0.050	0.168	0.055	11.216
100	0.069	0.077	11.004		0.069	0.082	0.072	3.507	0.087	25.205	0.070	1.290	0.075	7.759
200	0.082	0.088	8.418		0.081	−0.690	0.084	2.557	0.100	23.078	0.081	−0.197	0.086	5.539
500	0.083	0.089	7.373		0.082	−0.605	0.084	1.654	0.096	15.955	0.083	0.320	0.088	6.276
1000	0.078	0.085	8.0672		0.077	−1.006	0.079	1.377	0.091	15.824	0.077	−1.178	0.083	6.041
ANN 2
(−cm)	Model’s; RMSE	Bulk density			Particle density		Porosity		Sand		Silt		Clay
		RMSE	Var (%)		RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)
0	0.062	0.090	44.795		0.065	3.495	0.074	18.984	0.061	−1.4383	0.063	0.735	0.071	13.825
10	0.054	0.079	45.688		0.055	1.939	0.066	21.240	0.054	−0.346	0.061	11.0896	0.066	21.544
20	0.055	0.082	48.997		0.056	1.218	0.062	13.777	0.064	16.515	0.053	−4.713	0.056	1.897
30	0.055	0.079	44.116		0.055	0.319	0.060	8.939	0.065	18.440	0.055	1.269	0.057	4.422
50	0.060	0.075	25.927		0.061	1.625	0.065	9.170	0.068	14.038	0.063	6.347	0.067	11.943
100	0.075	0.086	13.880		0.075	0.528	0.077	2.454	0.082	8.963	0.080	6.047	0.082	8.753
200	0.098	0.103	5.356		0.098	0.001	0.102	3.909	0.107	9.005	0.101	3.209	0.105	7.686
500	0.087	0.095	8.460		0.087	−0.027	0.089	1.565	0.097	11.781	0.088	0.728	0.091	4.904
1000	0.084	0.086	3.339		0.083	−0.141	0.088	5.358	0.087	4.246	0.086	2.633	0.092	10.162
ANNo
Model’s; RMSE	Bulk density		Particle density		Porosity		Sand		Silt		Clay
	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)	RMSE	Var (%)
0.080	0.094	17.065	0.080	−0.075	0.085	5.7464	0.081	1.255	0.080	0.037	0.082	2.641	0.118	46.825

Var (%) means the increasing (+) or decreasing (−) in the RMSE value of an output (matric potentials, ) due to the substitution of a specific input parameter by its mean value.