Use of a Digital Camera to Monitor the Growth and Nitrogen Status of Cotton

Table 4

Exponential equations showing the relationships between canopy cover and the three crop properties of two cotton cultivars grown with five N rates in experiment 1.

Crop parameter	N rates	k (mean ± S.D.)	b (mean ± S.D.)	RMSE	𝑅^2
Aboveground total N content	N0	0.497±0.034	4.238±0.042	1.793 g m^−2	0.949**
	N1	0.549±0.021	4.241±0.032	1.459 g m^−2	0.965**
	N2	0.632±0.027	4.248±0.025	1.328 g m^−2	0.975**
	N3	0.752±0.024	4.256±0.023	1.287 g m^−2	0.978**
	N4	0.801±0.037	4.265±0.034	1.384 g m^−2	0.957**
Leaf area index	N0	0.368±0.079	2.596±0.257	0.565 m^2 m^−2	0.864*
	N1	0.384±0.043	2.896±0.157	0.508 m^2 m^−2	0.910**
	N2	0.46±0.057	2.907±0.211	0.194 m^2 m^−2	0.9618**
	N3	0.465±0.048	2.959±0.129	0.265 m^2 m^−2	0.966**
	N4	0.481±0.086	2.988±0.227	0.496 m^2 m^−2	0.939**
Aboveground biomass	N0	20.043±11.741	3.465±0.596	348.664 g m^−2	0.758*
	N1	23.769±10.431	4.378±0.499	225.427 g m^−2	0.885*
	N2	27.519±14.982	4.632±0.699	139.005 g m^−2	0.864**
	N3	28.283±8.986	4.674±0.388	124.954 g m^−2	0.948**
	N4	28.736±6.956	4.697±0.377	192.813 g m^−2	0.938**

Note: ∗∗indicates significant difference at 𝑃<0.01; ∗indicates significant difference at 𝑃<0.05.