The effects of nitrogen, phosphorus, and potassium levels on the yield and fiber quality of cotton cultivars

The objective of this work was to evaluate the effects of nitrogen (N), phosphorus (P), and potassium (K) levels on the yield and fiber quality of cotton cultivars with different maturation cycles and chemical fertility gradients. The experimental design was a randomized block design with five replicates. The treatments consisted of a combination of 13 cotton cultivars (FM 910, FM 993, IMA 12427, IMA 1595, IMA 1600, IMA 2059, IMA 278, IMA 2968, IMA 3869, IMA 474, IMA 6035, IMA 690, and IMA 8276) at three levels of fertilization (50%, 100%, and 150% of the recommended dose of each nutrient) with nitrogen, phosphorus, and potassium. Cultivars IMA 2059, IMA 2968, and IMA 8276 had little or no response to increase fertility levels. However, they all produced more than 1000 kg ha(-1) of lint. Cultivars IMA 1600, IMA 3869, IMA 474, IMA 6035, and IMA 690 presented higher yields at the 150% level when compared to the 50% level, but these same yields were achieved with just the 100% recommended dose. IMA 6035 was the most productive. It had a lint yield of 1500 kg ha(-1). In general, the use of 100% or 150% of the recommended nitrogen (N), phosphorus (P) and potassium (K) dose increased fiber quality, though this did not apply to micronaire values. These values decreased with increased fertility in 70% of the analyzed cultivars. We concluded that the level of soil fertility affects cotton yield and fiber quality responses. We found that demanding cultivars may increase yield. However, increasing the dose of nutrients can increase the cost of production in less demanding cultivars.