Soil Organic Matter and Macronutrient Levels after Mill Mud Application to Sugarcane Growing in a Sand Soil.

Authors: Morris, Dolen; GILBERT, R - UNIV FL-EREC,BELLE GLADE; RAINBOLT, C - UNIV FL-EREC,BELLE GLADE; PERDOMO, R - FL CRYSTALS CORP,SOUTH B; POWELL, G - FL CRYSTALS CORP,SOUTH B; EILAND, B - FL CRYSTALS CORP, SOUTH B; MONTES, G - FL CRYSTALS CORP, SOUTH B

Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 5/2/2007
Publication Date: 6/13/2007
Citation: Morris, D.R., Gilbert, R.A., Rainbolt, C.R., Perdomo, R.E., Powell, G., Eiland, B., Montes, G. 2007. Soil organic matter and macronutrient levels after mill mud application to sugarcane growing in a sand soil. American Society of Sugar Cane Technologists. 70(1):17-18.

Interpretive Summary: Mill mud contains high nutrient levels and is often applied to sugarcane grown in sand soils at high rates. The potential for nutrient leaching into the subsoil is not known. An experiment was conducted to assess soil organic matter and macronutrient movement into three soil depths (0- to 6-, 6- to 12-, and 12- to 18-in depths) after three sugarcane harvests. Treatments consisted of all combinations of three cropping system practices before planting sugarcane (fallow, soybean green manure, and soybean forage removed), two mill mud rates (none and 110 tons acre-1 applied one time before planting), and two fertilizer practices (low-enough to keep the plants alive and adequate-extension service recommendations). Cropping system practices generally had little effect on soil nutrient levels. Also, fertilizer effects were small compared to effects due to mill mud. After 3 years, mill mud application increased soil organic matter (OM), total N, and total C compared with no mill mud by 1.2, 0.02, and 0.52%, respectively, in the 0- to 6-in depth. In the 6- to 12-in soil depth, OM, N, and C increases of mill mud treatments compared to no mill mud treatments were smaller (0.2, 0.01, 0.1%, respectively). In the 12- to18-in depth after 3 years, changes in OM, N, and C were minor. Extractable P, K, Ca, and Mg were increased by 117, 16, 1154, and 53 ppm in the surface soil after 3 years when comparing mill mud to no mill mud treatments. But in the 6- to 12-in depth, only P, Ca, and Mg were increased slightly (8.4, 146, 8.2 ppm, respectively) due to mill mud application. There was little effect of mill mud on P, K, Ca, and Mg in the 12- to 18-in soil depth. Extractable Si was little affected by mill mud application at any soil depth. Soil pH was increased by mill mud application after 3 years at all 3 soil depths. Soil pH increases of mill mud treatments above no mill mud were 1.1, 0.8, and 0.8 pH units for 0- to 6-, 6- to 12-, and 12- to 18-in depths, respectively. The data suggest that when mill mud is applied to sugarcane on a sand soil, organic matter is conserved and macronutrients are not readily leached into subsoil. Mill mud is an effective liming material for sand soils that can increase soil pH to an 18-in depth. [GRACEnet Publication]

Technical Abstract: Mill mud contains high nutrient levels and is often applied to sugarcane grown in sand soils at high rates. The potential for nutrient leaching into the subsoil is not known. An experiment was conducted to assess soil organic matter and macronutrient movement into three soil depths (0- to 6-, 6- to 12-, and 12- to 18-in depths) after three sugarcane harvests. Treatments consisted of all combinations of three cropping system practices before planting sugarcane (fallow, soybean green manure, and soybean forage removed), two mill mud rates (none and 110 tons acre-1 applied one time before planting), and two fertilizer practices (low-enough to keep the plants alive and adequate-extension service recommendations). Cropping system practices generally had little effect on soil nutrient levels. Also, fertilizer effects were small compared to effects due to mill mud. After 3 years, mill mud application increased soil organic matter (OM), total N, and total C compared with no mill mud by 1.2, 0.02, and 0.52%, respectively, in the 0- to 6-in depth. In the 6- to 12-in soil depth, OM, N, and C increases of mill mud treatments compared to no mill mud treatments were smaller (0.2, 0.01, 0.1%, respectively). In the 12- to18-in depth after 3 years, changes in OM, N, and C were minor. Extractable P, K, Ca, and Mg were increased by 117, 16, 1154, and 53 ppm in the surface soil after 3 years when comparing mill mud to no mill mud treatments. But in the 6- to 12-in depth, only P, Ca, and Mg were increased slightly (8.4, 146, 8.2 ppm, respectively) due to mill mud application. There was little effect of mill mud on P, K, Ca, and Mg in the 12- to 18-in soil depth. Extractable Si was little affected by mill mud application at any soil depth. Soil pH was increased by mill mud application after 3 years at all 3 soil depths. Soil pH increases of mill mud treatments above no mill mud were 1.1, 0.8, and 0.8 pH units for 0- to 6-, 6- to 12-, and 12- to 18-in depths, respectively. The data suggest that when mill mud is applied to sugarcane on a sand soil, organic matter is conserved and macronutrients are not readily leached into subsoil. Mill mud is an effective liming material for sand soils that can increase soil pH to an 18-in depth. [GRACEnet Publication]