Estimation of nitrate nitrogen content in cotton petioles under drip irrigation based on wavelet neural network approach using spectral indices

Table 5 Quantitative relationship between trilateral parameters and NO₃⁻–N content in petioles

Trilateral parameters	Functional model	Regression equation	R²	RMSE (g/L)
Dr	Linear	y = − 1E + 06x + 21,084	0.64	1.40
	Exponential	y = 59,355e^−160.9x	0.61	1.45
	Quadratic	y = − 2E + 08x² + 6E + 06x − 23990	0.67	2.93
SDr	Linear	y = − 12,321x + 13,673	0.52	2.28
	Exponential	y = 18,355e^−1.876x	0.47	2.59
	Quadratic	y = − 58,926x² + 48,072x − 895.38	0.60	2.53
Dy	Linear	y = − 1E + 08x + 1114.1	0.72	1.08
	Exponential	y = 2691.4e^−17931x	0.67	1.82
	Quadratic	y = − 4E + 12x² − 5E + 08x − 9212.4	0.84	2.73
SDy	Linear	y = − 193,244x − 1139.4	0.73	2.91
	Exponential	y = 1924.3e^−29.42x	0.67	2.54
	Quadratic	y = − 8E + 06x² − 905,730x − 16273	0.79	2.51
Db	Linear	y = 4E + 06x − 836.47	0.80	1.04
	Exponential	y = 2036.5e^619.48x	0.72	1.50
	Quadratic	y = − 3E + 09x² + 2E + 07x − 14359	0.89	1.64
SDb	Linear	y = 498,071x − 9405.9	0.81	1.45
	Exponential	y = 492.37e^78.986x	0.80	1.53
	Quadratic	y = 9E + 06x² − 84,605x − 199.84	0.82	1.98

ISSN: 1746-4811