Abstract
A field experiment was carried out to study the effect of different rates of potassium (K) fertilizer [0, 50, 100, and 150 potassium oxide (K2O) ha–1] in the presence of increased supply of nitrogen (N) (120, 180, and 240 kg N ha–1) on cotton (Gossypium hirsutum L.) yield and the N and K use efficiencies using the 15N isotopic dilution technique. Potassium fertilizer increased cotton yield, which was significant and more pronounced with the application of N in the high level (N3). The greatest cotton yield (6442 kg ha–1) was obtained in N2K3 treatment with an increase of 14% over the control. In addition, K fertilizer significantly increased N uptake efficiency in the N2 and N3 treatments. The greatest N uptake efficiency (98%) was in N2K3 treatment. The greatest K uptake efficiency (42%) was occurred in N3K1 treatment. In conclusion, the use of K fertilizer could be useful when growing cotton in soils of moderate to high N content to improve N uptake efficiency and consequently increase cotton yield.
Acknowledgments
The authors thank the director general and head of the Agriculture Department, Atomic Energy Commission of the Syria, for their encouragement and financial support.