Cotton

Cotton is a nutrient‑intensive crop with highly specific demands that shift as the plant transitions from vegetative growth to reproductive development. Achieving high lint yield, strong fiber quality, and uniform boll set requires a fertility program that delivers the right nutrients in the right form at the right time. Early‑season nutrition drives root establishment and vegetative vigor, while the squaring and flowering stages place heavy demands on potassium, sulfur, and other key nutrients that support fruit retention, boll fill, and fiber elongation. Because cotton’s nutrient uptake curve peaks during these reproductive stages, consistent, plant‑available nutrition is essential to minimizing stress and maximizing both yield and fiber quality.

Tessenderlo Kerley fertilizers provide readily available, crop‑safe nutrients formulated to match these physiological needs, helping growers maintain a productive canopy and optimize boll development. The following guidelines outline how to integrate our products into a nutrition program throughout the growing season.

Nitrogen (N)

Nitrogen is critical for driving early vegetative growth, establishing boll sites, and maintaining a balanced canopy capable of supporting boll retention. Adequate N supply supports photosynthetic capacity, which in turn fuels boll set and fiber development. However, excess nitrogen, especially later in the season, can delay maturity, stimulate vegetative regrowth at the expense of fruiting, and contribute to poor boll retention.

Controlled‑release nitrogen sources such as N‑Sure®, which contains triazone nitrogen, deliver a steady, predictable supply of N when applied through irrigation or as a side-dress application. The gradual breakdown of the triazone molecule improves uptake efficiency and reduces leaching losses, an important advantage in sandy soils or high‑rainfall environments. When blended with conventional N sources like UAN‑32, triazone helps moderate release patterns and enhances overall nitrogen use efficiency. N‑Sure is also an effective foliar option, providing in‑season nutritional support when tank‑mixed with compatible fertilizers and crop protection products, without overstimulating vegetative growth.
Potassium (K)

Potassium plays a central role in cotton yield and fiber quality, influencing boll retention, fiber elongation, and overall plant stress tolerance. Adequate potassium supports stomatal regulation, water balance, and carbohydrate transport to developing bolls—processes that are critical during peak fruiting. Liquid potassium fertilizers are well suited for fertigation or side-dress systems, allowing targeted applications during squaring, flowering, and boll fill when potassium demand is highest.

KTS® provides readily available potassium along with thiosulfate sulfur, improving nutrient uptake efficiency. The thiosulfate component is particularly beneficial in calcareous soils, where its acidifying effect increases the availability of phosphorus, iron, and manganese—nutrients important for root growth and photosynthetic activity. Thiosulfate is also a proven nitrification inhibitor, when applied in a banded application, thiosulfate can help to improve nitrogen use efficiency and reduce nitrogen losses.

K‑Row 23® is ideal for early‑season starter potassium applications because it is seed‑safe and can be placed close to the seed or young plants. It also supports higher in‑season application rates, which is valuable during periods of rapid boll development. Together, these products allow growers to align potassium supply with crop needs throughout the season, helping ensure strong boll retention and premium fiber quality.

Sulfur (S)

Sulfur supports protein synthesis, enzyme activation, and chlorophyll formation—processes essential for vigorous early growth and sustained boll production. Adequate sulfur also enhances nitrogen use efficiency by improving the balance between amino acid and protein formation. Thio‑Sul® provides a highly soluble, plant‑available source of sulfur that moves efficiently through the soil profile and supports consistent uptake throughout the season. Thiosulfate is also a well‑documented nitrification inhibitor; when banded in the soil, it slows the conversion of ammonium to nitrate, helping retain nitrogen in the root zone, reduce leaching losses, and improve overall N use efficiency. The thiosulfate form found in Thio‑Sul, KTS, and CaTs also promotes better nutrient mobility and can help mitigate bicarbonate issues in alkaline irrigation water. In high‑pH or calcareous soils, thiosulfate sulfur acidifies the rhizosphere, improving the availability of phosphorus, iron, and manganese—nutrients critical for root growth, leaf color, and plant vigor. Maintaining adequate sulfur levels supports balanced nutrition, improved nitrogen efficiency, and the strong vegetative and reproductive growth needed for high‑yielding, high‑quality cotton.
Calcium (Ca)

Calcium is essential for cell wall strength, root development, and overall plant structure in cotton. Adequate Ca supports early root growth, reduces seedling disorders, and contributes to stronger fruiting branches capable of carrying heavy boll loads. Because calcium is relatively immobile within the plant, a consistent supply is needed during early vegetative growth and throughout boll development.

CaTs® improves calcium uptake by supplying a highly soluble, readily available form of Ca that moves efficiently through the soil profile, while its thiosulfate component helps manage high pH and increases the availability of nutrients such as phosphorus and iron. Since CaTs contains no nitrogen, it can be applied during growth stages when additional N should be limited. Additionally, CaTs blends with many forms of nitrogen, and can add both calcium and sulfur when nitrogen is needed. CaTs also supports in‑season salinity management by improving soil structure, enhancing water infiltration, and aiding salt leaching. Maintaining adequate calcium levels strengthens root systems, supports boll set, and improves overall plant resilience.