Objectives Nitrogen supply is necessary for the rapid and healthy growth of cotton, however lint cotton production is sensitive to excessive N supply. We investigated the appropriate nitrogen (N) application rates for efficient lint cotton production and nutrient absorption, to provide theoretical basis for efficient yield and nutrient management of cotton.

Methods  A field experiment with split-plot design was conducted in 2019 and 2020 in Anyang, Henan Province.The main plot was N application rate: 0, 60, 120, 180, 240, 300, and 360 kg/hm²; the sub-plot was two cotton cultivars, Jimian228 (middle maturity) and Lumianyan28 (mid-early maturity), which were the main high-yielding cultivars grown in the areas of the Yellow River Valley. The shoot biomass, yield, and above ground N, P and K contents were determined.

Results The shoot biomass of Jimian228 increased significantly with the increase of N application rates from 0 to 240 kg/hm², but was not affected by N application rates which exceeded 240 kg/hm². The shoot biomass of Lumianyan28 started decreasing when N application rates exceeded 180 kg/hm². N application significantly increased the accumulation of N, P, and K in the shoots of Jimian228 and Lumianyan28. The increment for Jimian228 were 37.5%, 23.5%, and 29.2%, where as for Lumianyan28, it was 47.2%, 34.0% and 35.5%, respectively, and Lumianyan28 was higher than in Jimian228. The increase of shoot biomass and NPK concentent contributed 65.9%–82.4% and 17.6%–34.1% to the increase of N, P and K accumulation in cotton shoot. The boll number per plant of Jimian228 and single boll weight of Lumianyan28 initially increased and then decreased with increasing N application rates. Simulated with a linear-plateau model, the optimal N application rates for the two cultivars were 180 kg/hm² and 188 kg/hm², which corresponded with lint yield of 1661 kg/hm² and 1538 kg/hm², respectively. The lint production efficiency of N, P and K generally decreased significantly with increasing N application rates. The lint production efficiency of P and K showed significantly positive relationship with that of N. The yield harvest index was negatively correlated with the accumulation of N, P and K, but positively correlated with the harvest index of N, P and K, indicating that it can be used as an indirect index of fertilizer use efficiency.

Conclusions N application increased NPK contents and the dry matter of cotton shoot, both NPK content and dry matter brought about enhanced shoot NPK accumulation, with the contribution rate of 65.9%–82.4% by dry matter and 17.6%–34.1% by higher NPK content. The lint cotton production efficiency of N was closely related to that of P and K. Therefore, N application could stimulate the absorption and utilization of P and K. Under conditions similar to the study area, the optimal N application rate for high yield and high use efficiency of nutrient for Jimian 228 and Lumianyan 28 are 180 and 188 kg/hm², respectively.