The main goal of this study was to determine the optimum irrigation scheduling method for cotton production in the southeastern coastal plain soils utilizing site-specific irrigation management. Soils in southeastern coastal plains have high variability that affects productivity and efficient farming. Advances in technology related to precision agriculture in the recent years have shown promise in site-specific irrigation.; Specifically, this study developed a protocol for generating a field water application map that accounts for soils spatial variability. The generated application maps were then remotely linked to a modified variable rate linear-move sprinkler irrigation to compare four irrigation scheduling methods. The five scheduling methods compared in this study were; Time Domain Tansmissometry (TDT) soil moisture sensors (Gro-point sensors), tensiometers, reference Evapotrispiration model (Jensen-Haise), automated evaporation pan, and no-irrigation (control).; The protocol for generating the site specific water application map were formulated as follows; (1) collecting and measuring the fields soil spatial parameters needed for irrigation scheduling; (2) dividing the field into management zones based on the spatial variability (3) selecting a scheduling method for each management zone; (4) calibrating the irrigation system for applying site-specific irrigation; (5) calibrating sensors and equipments under field conditions; (6) calculating irrigation depths and create field application map; (7) managing the site-specific irrigation system to irrigate the field based on the application map.; The soil electrical conductivity (SEC) and soil texture data were used successfully to divide the test field into 5 management zones (classes). There were no significant differences in plant available water (PAW) among the five soil classes except for class III and V. Based on the pressure plate tests, there were no significant differences in water holding capacity of the areas of the test field with higher clay contents compared to areas with less clay and high sand contents. The average available soil moisture for the test field (Varina soil) was 0.10 cm/cm. The depth to the Bt horizon varied between 25 to 47 cm in the test field. There was a strong correlation between the depth to the Bt horizon and SEC. The calibration equations for different types of TDT sensors and tensiometers were developed under actual field conditions. Procedures for calculating the irrigation depth for each irrigation scheduling method were developed.; There were no significant differences in seed cotton yield between the four irrigation scheduling treatments. (Abstract shortened by UMI.)
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