Use of Biochars Produced from Local Residue Feedstocks to Grow Sugarcane on Sandy Soils in South Florida.

Sugarcane production on sandy soils of South Florida has been gaining interest due to the need to expand sugar and bioenergy production, and to gradually alleviate production in organic soils. Biochar application has the potential to improve soil physiochemical properties of sandy soils with low organic matter by increasing carbon content, water holding capacity (WHC), nutrient retention and cycling. The purpose of this experiment is to provide an alternative use for local feedstocks as biochars and evaluate their potential to improve soil fertility and sugarcane crop productivity. Mill ash and three biochars produced from hardwood yard waste (HY), horse barn shavings with manure (HM), and rice hulls (RH) were incorporated at 1% and 2% (by weight) in 70 gallon lysimeters. The experimental design consisted of a randomized block set-up including four treatments and one control, with four replications of each. Results have shown the control to have higher bulk density, lower WHC and lower organic matter content compared to all treatments. Soil pH shifted from being slightly acidic to neutral or basic with treatment incorporation. Monthly water samples have not shown a specific nutrient concentration trend over time; however, mill ash applied at 1% and 2% have shown lower total phosphorus, total dissolved phosphorus, ortho-phosphate, and dissolved organic carbon in comparison to HM 2% and RH 1% and 2%. Tiller count and dewlap height has shown variable results; however, HM 2% presented significantly lower amount of tillers. Future work will continue to include monthly water samples and plant measurements until harvest, and the analysis of a second and third soil sample. Yield and sucrose content will also be evaluated at the end of the experiment.