|Richard Jr, Edward|
Submitted to: International Society of Sugarcane Technologist Agronomy Workshop
Publication Type: Abstract Only
Publication Acceptance Date: March 3, 2009
Publication Date: May 24, 2009
Citation: Johnson, R.M., Viator, R.P., Richard Jr, E.P. 2009. Determination of Yield and Soil Variability in Louisiana Sugarcane Using Selected Tools of Precision Agriculture [abstract]. International Society of Sugarcane Technologists Agronomy Workshop, Abstracts of Communications. pp. 42 - 43. Technical Abstract: Precision agriculture is a production strategy that may help sugarcane producers decrease input costs, maximize profits, and minimize any negative environmental impact through better management of soil and crop variability. To determine the extent of variability present in commercial sugarcane fields in Southern Louisiana, we measured yield variability in several commercial fields that were planted to newly released sugarcane cultivars L 97-128 and HoCP 96-540. These tests were conducted from 2006 to 2008 and included plant-cane and ratoon crop fields. In each study, selected rows from each field were harvested in 15-30 m increments using a single-row chopper harvester, with gross-cane yields determined using a field transport wagon equipped with electronic load sensors. In 2007 and 2008, aerial imagery was also obtained from several of the fields to determine if it could be used to estimate gross cane levels prior to harvest. Soil samples were collected (0-15 cm) from each field and analyzed for major chemical properties. In 2008, a Veris® soil pH and electrical conductivity (EC) mapping system was also used to document the soil EC and pH variability present in a 25-ha fallow sugarcane field and to determine the utility of this system to the Louisiana Sugarcane Industry. In all cases, yield and soils data were analyzed by both conventional (univariate, bivariate) statistics and geostatistical techniques. Aerial imagery was compared to block-kriged yield maps using GIS techniques. Results indicated that gross-cane yields from the majority of test sites were not normally distributed and were also spatially correlated. The range of spatial correlation for gross-cane yields for the two varieties varied from 0 to 330 m. Soil properties also exhibited a significant degree of non-normality and spatial correlation, with soil P showing the greatest degree of variability. A high degree of variability was also documented with the Veris® mapping system with soil pH varying from 4.5 to 7.4 and soil EC from 0 to 80 mS m-1. At a speed of 5 km h-1 the system obtained 42 pH samples ha-1 and continuous soil EC data. Finally, biomass estimates derived from aerial imagery were well correlated with gross-cane yields from direct field measurements. These combined results clearly document that sufficient variability exists in Louisiana sugarcane production systems to justify a precision agriculture approach. The Veris® EC and pH system appear to be well suited to mapping variability in these properties at a field level and may assist producers in developing lime variable rate application maps. These data also indicate that it may be possible to utilize remote sensing techniques to estimate cane yields prior to harvest. This would allow growers and mills to more effectively manage harvest schedules to insure maximum yields from individual fields.