Evaluation of Two Irrigation Scheduling Methods and Nitrogen Rates on Corn Production in Alabama

Table 1

van Genuchten equation parameters from 2014, percentage (sand, silt, and clay), and soil textural class for three soil depths at the TVREC. The parameters from 2014 were used during both growing seasons.

Depth (cm)	0–15	15–30	30–60
θr^ǂ	0.0808	0.0969	0.1048
θs^§	0.4095	0.4779	0.536
α^¶	0.089	0.0132	0.0178
N^£	1.4669	1.365	1.3098
m^¤	0.3183	0.2674	0.2365
θs − θr^¥	0.3287	0.381	0.4312
% sand	16.18	10	9.76
% silt	51.05	43.45	35.74
% clay	32.77	46.55	54.5
Textural class	Silty clay loam	Silty clay	Clay

^ǂ Residual soil water content (cm³ cm⁻³). ^§Saturated soil water content (cm³ cm⁻³). ^¶Parameter related to the inverse of the air entry suction (cm⁻¹); ^£n curve shape parameters (empirical parameter). ^¤m = (1 − 1/n). ^¥θ_r and θ_s are the residual and saturated soil water contents (cm³ cm⁻³).