LIME

Check lime requirements by conducting soil tests. Liming is primarily a method of correcting soil pH, but there are several other benefits to include:

• To adjust soil pH to improve fertilizer use efficiency by maximizing nutrient availability.
• To supply calcium, an essential plant food nutrient. If magnesium is deficient, use dolomitic limestone.
• To reduce aluminum and manganese toxicity.
• To enhance the activity of soil microorganisms.
• To improve the activity of soil applied herbicides.
• To decrease the total amount of lime applied, consider variable rate lime applications.
• Soil pH <5.5 on sandy loam & silt loam soils.
• Soil pH <5.2 on clay loam & clay soils.
• The lime rate should be based on soil test and ideally should raise soil pH to 6.5.
• It is ideal to broadcast lime to fallow fields or in crop during the fall or winter.
• Apply lime after precision leveling.

Lime when:

• Soil pH <5.5 on sandy loam & silt loam soils.
• Soil pH <5.2 on clay loam & clay soils.
• The lime rate should be based on soil test and ideally should raise soil pH to 6.5.
• It is ideal to broadcast lime to fallow fields or in crop during the fall or winter.
• Apply lime after precision leveling.

How long will it take for lime to work?

• The lime reaction rate will depend primarily on the lime quality, which is based on two factors: 1) the chemical purity of the liming material and, 2) the particle size distribution.
• Chemical purity is expressed as the calcium carbonate equivalent (CCE) of the liming material. Pure calcium carbonate has a CCE of 100% and most soil testing labs assume that your liming material has a CCE of 100% when making lime recommendations. If your material has a CCE less than 100%, you will have to apply more lime. For example if your recommendation is for 1 ton of lime with a CCE of 100%. You will need to apply 2 tons of a material with a CCE of 50% (100/50 x 1 ton/A = 2) or 1.33 tons of a material with a CCE of 75% (100/75 x I ton lime/A = 1.33).
• Particle size distribution is expressed as the percentage of the liming material that passes through screens of various sizes. Small lime particles will react more quickly and larger lime particles more slowly. Ideally, your liming material will have a good distribution of particle sizes with both smaller particles to quickly raise the soil pH and larger particles to provide longer term soil pH control. Current Louisiana recommendations for ground lime specify the materials should meet the following minimum standard - Ninety percent shall pass through a ten-mesh sieve, fifty percent shall pass through a sixty-mesh sieve, and twenty-five percent shall pass through a one-hundred-mesh sieve. The larger the screen size, the smaller the lime particles.
• Typically, with a good quality lime, the biggest change in pH after application will occur within 3-4 months. The pH may continue to increase for 6-12 months.

MICRONUTRIENTS, ZINC (Zn)

• Apply only if soil tests or tissue analyses indicate deficiencies. 

Prepared by Dr. Kenneth Gravois, Sugarcane Specialist, LSU AgCenter, from information obtained from research conducted at both the LSU AgCenter and USDA-ARS, Sugarcane Research Unit. Research supported in part by funding from the American Sugar Cane League. 

NITROGEN

• For efficient nitrogen utilization, it is important that soil pH is slightly acidic to neutral (ideally 6.0 to 6.5) and adequate plant available P & K are available.
• Nitrogen recommendations are based on tests where UAN 32% was the primary nitrogen source.
• Recommendations are based on data with commercial varieties and on light and heavy soils at multiple locations on plant-cane through third stubble crops.
• Higher than recommended rates of nitrogen may increase tons of cane per acre, but also decrease sugar per ton of cane. Recommended rates will maximize sugar per acre yields with optimum sugar per ton of cane.
• Apply nitrogen between April 1 and April 30 – earlier if the crop is more advanced and later if the crop is less advanced.
• Avoid excess levels of nitrogen to reduce rust severity.

PHOSPHOROUS (as P205)

• When phosphorous prices are high consider applying only when soil test levels are low or very low.
• Sugarcane removes approximately 1 lb. of P2O5 per ton of cane from the soil. Availability of phosphorous depends upon soil pH & soil type. Optimal soil pH for best phosphorous availability is 6.2.
• Excess phosphorous may lead to increased rust severity.

POTASSIUM (as K2O)

• Recommendations are based on soil tests.
• When potash prices are high, consider applying only when soil test levels are low or very low. Although not specifically recommended above, if one is not considering applying potassium at all, consider applying 60 lbs/acre to fields testing very low or low.
• Sugarcane removes approximately 3 lbs of K2O per ton of cane from the soil.

  SULFUR (S)

• Recommendations are based on soil test results.
• Stubble cane is more likely to respond to sulfur fertilizer than plant-cane.
• Response is more likely on medium-heavy to heavy textured soils.
• Excess sulfur may lead to increased rust severity.