Like other plants, sugarcane requires quite a few nutrients in the soil to grow healthily. As the plants grow, they use up nutrients in the soil. Growers generally replace these nutrients by adding fertilizers. Over time, scientific research has determined optimum fertilizer amounts for the healthiest and most productive sugarcane plants.
Sugarcane requires fewer nutrients than many other crops, so it also requires less fertilizer than some other plants. For example, it uses around half as much phosphorous as sweet corn and a quarter of the amount of phosphorous that lettuce uses. Growing sugarcane can pollute the environment less than crops that require more fertilizer, because there is less of a chance for fertilizer-polluted runoff. Fertilizer helps sugarcane grow to a certain point, but too much fertilizer stops helping it grow and may even harm plants.
Sugarcane needs nitrogen, phosphorous, potassium, magnesium, sulfur, calcium, iron, copper, chlorine, zinc, boron, molybdenum and manganese to grow; growers need to provide some of these nutrients more than others. Nitrogen is one of the most important nutrients for sugarcane growth, because it helps the plant grow leaves and produce sugar. Magnesium and phosphorous in the right amounts also help plants produce the most sugar they can. Sulfur can help keep the soil at the right pH for sugarcane, and silicon makes sugarcane more resistant to droughts, pests and diseases.
Research shows that up to 150 lbs. of nitrogen per acre can increase sugarcane yields, but that more than 150 lbs. does not continue to help plants produce more sugar. Sugarcane in sandy soils requires more fertilizer than sugarcane in heavier clay soils, and as little as 80 lbs. of nitrogen fertilizer per acre can be enough.
Research from the University of Florida Institute of Food and Agricultural Sciences shows that up to 32 lbs. of phosphorous per acre can increase sugarcane production in phosphorous-poor soils. Additional phosphorous over 32 lbs. will not help sugarcane. Soils with naturally moderate or high phosphorous contents may require less than 32 lbs. of phosphorous per acre, so farmers should test their soil nutrients before applying fertilizers.
Soil Testing and Fertilizer Amounts
Before applying fertilizer, have soil nutrient levels and pH tested at a lab or university. Experts can measure nutrients in the soil and recommend how much fertilizer to add. Some nutrients, such as sulfur, alter the soil pH. The U.S. Environmental Protection Agency recommends 24 lbs. of sulfur per acre of sugarcane, but only if soil tests reveal that the soil needs sulfur. Other nutrients, like iron, manganese and aluminum, can harm plants in excess amounts, so get a test-based recommendation on these nutrients too. Use caution when applying fertilizers, because excessive use can harm plants and create polluted water runoff.