|Richard Jr, Edward|
Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/18/2004
Publication Date: 7/25/2005
Citation: Johnson, R.M., Richard Jr, E.P. 2005. A Comparison of Conventional and Variable Rate Lime Application Methods in South Louisiana Sugarcane Fields. CD-ROM. ASA-CSSA-ASSA, Madison, WI. Proc. of the 7th International Conference on Precision Agriculture. p. 173 Interpretive Summary:
Technical Abstract: Louisiana sugarcane producers continue to face increased economic pressure. Growers must find ways to decrease costs and maximize profits, while minimizing potential negative environmental impacts. Precision agriculture, specifically, variable rate lime and fertilizer application, may offer an important tool to accomplish this objective. Two studies were conducted in plant-cane crops at commercial sugarcane farms in South Louisiana. The first study was initiated in 2002 at a 20-ha field in Terrebonne parish and the second study in 2003 at a 12-ha field in Plaquemine parish. In each study, a conventional (uniform rate) lime application method was compared to a variable-rate application method and a no lime control. Prior to lime application, soil samples (0-20 cm) were taken from each site on a 0.4 ha grid. A random soil sample was also collected from each field to determine the lime rate, based on current recommendations, for the conventional treatment. Variable rate application maps were constructed from the soil data using variogram analysis and kriging. Soil properties determined included: OM, pH, buffer pH, Ca, Mg, K, P, CEC, and S. Treatments were applied in strips that were 14 rows (~ 25 m) wide and ranged from 300 to 450 m in length. Lime for both conventional and variable rate treatments was applied with an Ag-Chem Terra-Gator at recommended rates. Each plot was harvested in 30-m sections to enable mapping of results. Plots were harvested with a single row, chopper sugarcane harvester with weights determined using a weigh wagon. In addition to weights, a random grab sample of cane billets was obtained from each section for sugar quality analysis. Yield, quality, and soils data were analyzed by both conventional statistics and geostatistical techniques. Kriged maps of sugarcane yield, quality, and soil properties were constructed to evaluate the effectiveness of the treatments.