More fertilizer does not necessarily mean more sugar. This study found that sugarcane did best when nutrients arrived at the right pace, apparently by changing the living community and chemical signals around its roots. Sugarcane is the world's most important sugar crop, but its long growing season requires a large and continuous supply of fertilizer.

That raises cultivation costs for farmers and weakens economic benefits. The challenge is therefore not simply growing more cane; the long growing season demands continuous fertilizer, increasing cultivation costs and reducing farmers’ economic benefits.

Controlled-release fertilizer releases nutrients slowly and continuously to support plant growth. Compared with traditional fertilizer, it releases nutrients at a stable rate over time through special packaging materials. That steadier supply can meet plant needs while reducing nutrient wastage and environmental pollution.

Studies have also linked suitable use with better nutrient use, yield, and crop quality. The central question is how this approach works in sugarcane soil, where soil metabolites and microorganisms may act together under controlled release fertilizer.

The amount of controlled-release fertilizer significantly affected sugarcane growth in the field. The highest fertilizer rate produced the most cane stems, but the highest sugar yield came from a moderate rate called D25. Plant height and stem thickness peaked under different rates, while sucrose content peaked under moderate D25 conditions.

In other words, more stems did not automatically mean more sugar. For better sugar yield and economic returns, D25 was identified as the effective threshold for applying controlled-release fertilizer. The soil around sugarcane roots contains communities of bacteria and fungi, and fertilizer changed some of those communities.

Bacterial diversity differed between fertilizer treatments, while fungal diversity stayed largely unchanged as the rate changed. The bacterial balance also shifted in relative abundance: Proteobacteria decreased under D two, while Actinobacteriota, Firmicutes, and another bacterial phylum increased.

In the fungal community, Basidiomycota decreased when CRF exceeded 1350 kilograms per hectare, while Rozellomycota increased notably under D two compared with other fertilizer rates. This is like adjusting the food arriving at a shared kitchen: change the delivery schedule, and different residents become more or less able to thrive.

The soil is not passive; its living community responds to the fertilizer schedule. The sugarcane root zone contains shifting communities of bacteria and fungi, while its soil chemicals span many biological jobs. That matters because changing fertilizer can reshape both the living community and the chemical processes surrounding the roots.

The main forces shaping the bacterial community were soil acidity, available nitrogen, and soil organic carbon. Which soil nutrients mattered most varied with the amount of controlled-release fertilizer applied. That means the fertilizer rate was connected to the soil conditions that organize the root-zone bacterial community, rather than acting as an isolated input.

The study used heatmaps to examine relationships among bacteria, fungi, and metabolites, and found significant concomitant relationships in sugarcane rhizosphere soils. For example, the dominant bacterium Sphingomonas had a significant negative relationship with several dominant fungal groups.

When one part of this underground community changed, another part tended to change with it. Changing the fertilizer reshaped the sugarcane root-zone community at several levels: particular bacteria, fungi, and small chemical compounds varied together.

This matters because it points to a connected underground response, rather than a change in one isolated group. The strong sugarcane yields led to a closer look at the microorganisms and soil chemicals involved under different fertilizer rates. The study recommends D25 when the goal is to maximize sugar yield and economic returns.

The chemical analysis linked controlled-release fertilizer with substances involved in sugarcane production, growth regulation, and interactions among microorganisms that affect fertilizer breakdown and use in the soil. For a farmer, the practical recommendation is to apply controlled release fertilizer under D twenty-five conditions to maximize sugar yield and economic returns.

Controlled-release fertilizer can improve sugarcane production by coordinating nutrient delivery with changes in the soil life around roots. The practical target is not the biggest dose, but the rate that produces the most sugar and better returns.