What Is the Best Fertilizer for Sugarcane?

There is no single “best” fertilizer for sugarcane because the crop’s needs shift with soil type, climate, and where you are in the harvest cycle. That said, nitrogen is consistently the most important nutrient, followed by potassium, with phosphorus playing a supporting role that matters less in many soils. Field trials across the tropics converge on that ranking, though how you deliver those nutrients and what you combine them with can make as much difference as which nutrients you choose.

Nitrogen Comes First

If you had to pick one nutrient to get right, it would be nitrogen. In a trial on sandy soil in Northeast Thailand, plots receiving nitrogen and potassium but no phosphorus produced roughly 87% more aboveground biomass than unfertilized controls, while plots receiving phosphorus and potassium but no nitrogen managed only about 26% more. Nitrogen was clearly the dominant limiting factor, with potassium a meaningful but distant second and phosphorus showing little effect on its own.¹ That pattern holds broadly across sugarcane-growing regions: the crop is a heavy feeder, and nitrogen is the nutrient it runs through fastest.

Getting the rate right matters. Research on Pakistani sugarcane found that the highest stripped-cane and sugar yields came at about 252 kg of nitrogen per hectare, applied in two equal splits. Pushing to 336 kg per hectare did not produce a statistically meaningful improvement. Meanwhile, sugar concentration in the juice peaked at a moderate rate of about 168 kg per hectare and actually trended downward at higher nitrogen levels, because excess nitrogen can delay maturity and dilute sucrose.² In other words, more nitrogen grows more cane up to a point, but it does not always grow sweeter cane. If you are paid on sugar content, blasting nitrogen is counterproductive.

Timing and Splitting Nitrogen Applications

How you time nitrogen can be as important as how much you apply. The same Pakistani study found that putting all the nitrogen down at planting, or waiting until 90 days after sowing to apply it all at once, both underperformed split applications. When the full dose went on at planting, much of it leached away before the crop could use it later in the season. When it all went on late, early growth suffered and the late-season nitrogen excess interfered with maturity.² Two equal splits, half at planting and half around 90 days, struck the best balance.

Controlled-release urea offers another way to solve the timing problem. A Chinese trial comparing conventional urea to a controlled-release formulation found that the slow-release version raised cane yield by about 7% while cutting nitrogen input by over 46%. When combined with organic fertilizer, the system achieved the highest sugar yield in the trial and improved beneficial soil microbial communities at the same time.³ For growers who can absorb the higher per-unit cost of controlled-release products, the savings on total nitrogen needed and the yield bump can more than compensate.

Potassium Is the Second Priority

Sugarcane pulls large quantities of potassium out of the soil. In that Northeast Thailand trial, the control plots removed about 39 kg of potassium per hectare in a single season, which represented roughly 15% of the soil’s available supply.¹ Potassium supports stalk strength, water regulation, and sugar transport within the plant. A field that grows sugarcane year after year without adequate potassium replacement will see declining yields, particularly on lighter or sandier soils that hold less potassium to begin with.

Potassium deficiency tends to show up as yellowing and browning of older leaf margins, and it becomes especially costly in ratoon crops, which rely on the same root system drawing from soil that has already been partially depleted. In practice, most balanced sugarcane fertilizer blends include potassium at rates comparable to nitrogen, though the exact ratio depends on what the soil already provides.

Phosphorus Plays a Smaller but Real Role

Phosphorus is essential for root development and energy transfer, but field trials consistently show it is less of a yield driver in sugarcane than nitrogen or potassium. That Thai trial found adding phosphorus without nitrogen barely moved the needle. Where phosphorus does matter is in the ratoon crop, when roots need to re-establish vigor after harvest. A Brazilian study on first-ratoon sugarcane found that combining a mineral phosphorus source (triple superphosphate) with poultry litter at modest rates produced the best overall development, with the recommended combination being about 2 tonnes per hectare of poultry litter plus 180 kg per hectare of triple superphosphate.⁴

The takeaway for phosphorus is that a soil test should guide your decision. On soils already well-supplied, extra phosphorus is wasted money. On soils that lock up phosphorus (highly weathered, acidic, iron-rich), organic sources like poultry litter can slowly release phosphorus and improve availability more than dumping mineral fertilizer alone.

Sulfur and Micronutrients

Beyond the big three of nitrogen, potassium, and phosphorus, sulfur is the secondary nutrient most likely to pay off in sugarcane. A multisite Brazilian study found that applying sulfur boosted stalk yield by an average of 5 to 7 tonnes per hectare in the first ratoon. The gains persisted into the second ratoon as a residual effect, increasing yield by 7 to 9 tonnes per hectare even without reapplication. Sulfate-based fertilizers worked faster, while elemental sulfur showed promise for longer-term supply.⁵ If your nitrogen source is urea rather than ammonium sulfate, you are not getting sulfur as a byproduct, and supplementation becomes worth considering.

Among micronutrients, iron and zinc have drawn the most research attention in sugarcane. An Egyptian study testing nano-scale iron and zinc found that nano-iron applied to the soil increased fresh stalk weight by about 27% and total fresh weight by roughly a third compared to nano-zinc treatments.⁶ Iron deficiency is not common in all sugarcane soils, but on calcareous or high-pH soils where iron becomes unavailable, targeted supplementation can pay off substantially.

Foliar Feeding as a Supplement

Foliar application of mixed nutrients is gaining traction as a mid-season boost rather than a replacement for soil-applied fertilizer. A large-scale Brazilian investigation across 13 field experiments tested two foliar sprays: one during active vegetative growth (containing nitrogen, potassium, sulfur, boron, copper, manganese, molybdenum, and zinc) and a second at the maturation stage (containing phosphorus, potassium, magnesium, sulfur, and boron). The combination increased bagasse, straw, and total energy production by roughly 8 to 10% compared to unsprayed controls, and improved photosynthetic and antioxidant enzyme activity within the plant.⁷

Foliar sprays are not a substitute for solid fertility programs, but they address a real limitation: by the time sugarcane reaches peak canopy, root uptake of some micronutrients slows, and leaf application bypasses that bottleneck. The economics depend on your spray infrastructure. If you already have equipment making field passes for pest or herbicide control, adding a foliar nutrient tank-mix costs relatively little.

Organic and Biological Alternatives

Organic amendments are not just a phosphorus play. A study in Egypt tested filter-cake compost enriched with phosphate-solubilizing bacteria and mycorrhizal fungi (beneficial root-colonizing fungi that extend the plant’s nutrient-scavenging network). The best-performing treatment achieved a cane yield of about 48.8 tonnes per hectare, roughly 2.5 times the unfertilized control and comparable to a full mineral fertilizer program.⁸ Sugar quality was also high, with a commercial cane sugar content of over 15%. The biological agents made the organic material work harder by solubilizing phosphorus and improving root access to soil nutrients.

Sugarcane also has a natural partnership with nitrogen-fixing bacteria, particularly a species called Gluconacetobacter diazotrophicus that lives inside the plant’s tissues and converts atmospheric nitrogen into a usable form. This bacterium is found in sugarcane-growing regions worldwide and contributes meaningful amounts of nitrogen to the crop without any fertilizer input.⁹ Commercial inoculants based on this and similar bacteria are available in some markets, and while they are unlikely to replace mineral nitrogen entirely, they can reduce the total amount you need to apply.

Why Ratoon Crops Need Different Attention

Sugarcane is typically harvested multiple times from the same root system. The initial planting is the “plant cane,” and subsequent harvests from the regrowing stubble are called ratoons. Yield tends to decline with each successive ratoon, and nitrogen deficiency is part of the reason. Research on sugarcane grown in heavy clay soils in Guadeloupe showed that nitrogen deficiency worsened with each ratoon crop, and the efficiency with which the plant actually captured applied nitrogen varied wildly, from as low as 6% to about 34%. A large fraction of the fertilizer, 30 to 40%, ended up immobilized in the soil organic matter rather than taken up by the plant.¹⁰

The practical implication is that later ratoons need more nitrogen per tonne of cane produced, and simply repeating the plant-cane fertilizer recipe for every ratoon leaves yield on the table. Many growers increase nitrogen rates by 10 to 20% for each successive ratoon, and some use tissue testing or diagnostic tools to fine-tune the rate rather than guessing. Eventually, the declining efficiency hits a point where replanting becomes more economical than fertilizing an aging ratoon.

Soil pH and Liming

Fertilizer selection does not matter much if your soil pH locks nutrients away before the plant can reach them. Sugarcane grows best in a slightly acidic to neutral pH range, roughly 5.5 to 7.0. On strongly acidic soils, aluminum becomes soluble and toxic to roots, and phosphorus binds into unavailable forms. Agricultural lime is the standard corrective, but its low solubility means the benefits are usually limited to the top layer where it is mixed in. Research on Brazilian sugarcane soils found that combining deep tillage with lime placement pushed the correction further into the root zone, sharply reducing the exchangeable aluminum fraction at depth and improving the overall production environment.¹¹

If you have never limed your sugarcane ground and your soil pH sits below 5.0, lime may do more for your yield than adding another bag of fertilizer. It is one of those interventions that does not show up on a fertilizer label but fundamentally changes how well the fertilizer you do apply actually works.

Delivering Fertilizer More Efficiently

How fertilizer reaches the root zone matters as much as what is in the bag. Subsurface drip irrigation combined with fertigation, where dissolved nutrients are fed through the irrigation system, has shown strong results in Indian trials. In Tamil Nadu, subsurface drip at full pan evaporation replacement with the full recommended dose of nitrogen and potassium delivered through the drip line produced significantly higher yields than conventional surface methods, while also saving up to about 35% of irrigation water.¹² Fertigation essentially delivers small, frequent doses of nitrogen and potassium directly where roots are active, reducing leaching and volatilization losses.

On the diagnostic side, tools like DRIS (Diagnosis and Recommendation Integrated System) use leaf nutrient ratios rather than single-nutrient thresholds to identify which nutrients are most out of balance. In a Florida study, fertilizing according to DRIS recommendations produced higher cane and sugar yields than programs guided by conventional soil testing or standard foliar analysis, because the approach prioritized overall nutrient balance rather than chasing individual deficiencies.¹³ A balanced nutrient supply matters more than getting any single nutrient to its maximum level.

Runoff and Environmental Tradeoffs

Sugarcane fertilization has an environmental dimension worth thinking about, especially if your fields drain toward sensitive waterways. Nutrient and sediment runoff from sugarcane fields can degrade water quality in rivers, estuaries, and coastal ecosystems.¹⁴ A Louisiana study tracking sugarcane-derived runoff into coastal bayous found that both nitrogen and phosphorus concentrations in the receiving water exceeded levels associated with eutrophication, and isotope analysis confirmed the nitrogen came from fertilizer rather than natural sources.¹⁵

The fertility strategies that help reduce runoff losses are largely the same ones that improve efficiency for the grower: split applications so less nitrogen sits unused in the soil during heavy rains, controlled-release products that meter out nutrients gradually, fertigation that places nutrients precisely in the root zone, and maintaining crop residue or trash blankets on the soil surface to slow water movement. Erosion control is especially critical on sandy soils, where the Thai research emphasized that conserving the nutrient-rich topsoil layer is as important for sustainable production as the fertilizer program itself.¹ In regions where environmental regulations are tightening around agricultural nutrient loading, these efficiency measures are becoming less optional and more mandatory.

1
Tropical Agriculture and Development. Effect of NPK Application on Growth, Yield and Nutrient Uptake by Sugarcane on a Sandy Soil in Northeast Thailand
2
ResearchGate. Effect of Nitrogen on Growth and Yield of Sugarcane
3
Industrial Crops and Products. Combined controlled-release urea and organic fertilizer boost sustainable sugarcane productivity by optimizing soil C–N properties and microbial communities
4
Nature. Agronomic performance of the first ratoon of sugarcane under phosphorus supply from a mineral and an organic source
5
Agronomy Journal. Sulfur fertilization sources for multisite sugarcane fields in Brazil
6
Sugar Tech. Sugarcane Response to Two Different Application Methods of Nano-Iron and Nano-Zinc
7
Agronomy Journal. Foliar nutrient application improves sugarcane bioenergy production by boosting photosynthetic enzyme activity and the antioxidant system
8
Scientific Reports. Impact of bio-organic amendment supplemented with phosphate-solubilizing bacteria and arbuscular mycorrhizal fungi on sugarcane cultivation
9
IOP Conference Series: Earth and Environmental Science. Isolation and nitrogen fixing efficiency of Gluconacetobacter diazotrophicus associated with sugarcane
10
Nutrient Cycling in Agroecosystems. Efficiency of nitrogen fertilizer in the sugarcane-vertical system in Guadeloupe according to growth and ratoon age of the cane
11
Geoderma. Effectiveness of deep lime placement and tillage systems on aluminum fractions and soil chemical attributes in sugarcane cultivation
12
Current Agriculture Research Journal. Optimization of Irrigation and Fertigation Scheduling for Sustainable Sugarcane Initiative through Subsurface Drip Irrigation in Western Zone of Tamil Nadu
13
Agronomy Journal. Soil Testing, Foliar Analysis, and DRIS as Guides for Sugarcane Fertilization
14
Soil and Tillage Research. Impacts of sugarcane soil and fertiliser management practices on nutrients and sediment in plot-scale runoff from simulated rainfall
15
PubMed. Nonpoint source of nutrients and herbicides associated with sugarcane production and its impact on Louisiana coastal water quality