|Richard Jr, Edward|
Submitted to: International Symposium on Precision Agriculture
Publication Type: Proceedings
Publication Acceptance Date: 10/16/2007
Publication Date: 10/23/2007
Citation: Johnson, R.M., Viator, R.P., Richard Jr, E.P. 2007. Variability of sugarcane yield in relation to soil variability in commercial Louisiana production systems. In: Proceedings of the IV International Symposium of Precision Agriculture (SIAP 2007), October 23-25, 2007, Vicosa, Brazil. 2007 CDROM.
Technical Abstract: Precision agriculture may offer sugarcane growers a management system that decreases input costs, maximizes profits, and minimizes any potential negative environmental impact. In this study we measured the variability present in three large commercial sugarcane fields in Southern Louisiana that were planted to newly released varieties. The first test was a first-ratoon field of sugarcane cultivar L 97-128, the second test was a plant-cane field of HoCP 96-540 and the third test was a first-ratoon field of HoCP 96-540. Selected rows from each field were harvested in 31-m increments using a single-row chopper harvester, with gross-cane yields determined using a field transport wagon equipped with electronic load sensors. Yield and soils data were analysed by both conventional (univariate, bivariate) statistics and geostatistical techniques. Gross-cane yields from all test sites were not normally distributed and were also significantly skewed with the means smaller than the median. In addition, both first-ratoon tests also exhibited significant kurtosis. The coefficient of variation ranged from 17.9% for the plant-cane HoCP 96-540 to 23.1% for the first-ratoon HoCP 96-540. Soil properties from all tests exhibited a significant degree of variability with the coefficients of variation ranging from 3.2% for soil pH in the first-ratoon L97-128 test to 30.4% for soil P in the plant-cane HoCP 96-540 test. Averaged over all tests, the greatest degree of variability was observed in soil P, followed by soil Mg, OM, K, S, Ca, CEC and pH. Soil pH and S exhibited non-normal distributions in all tests and soil P, K, Ca, CEC and OM exhibited non-normal distributions in at least one test. All of the yield and soil data collected were spatially correlated, with the exceptions of L 97-128 gross-cane yield and soil Mg and S from the HoCP 96-540 plant-cane test. The range of spatial correlation for gross-cane yields from the HoCP 96-540 tests was 33-m for the plant-cane and 330-m for the first-ratoon tests, respectively. Examination of kriged contour maps of soil properties shows a relation between gross-cane yields and soil pH, Ca and K levels. Finally, biomass estimates derived from aerial imagery correlated well with gross-cane yields from direct field measurements. The combined sugarcane yield and soils data indicate that sufficient variability exists in Louisiana commercial sugarcane fields to justify a site specific management approach.