Stimulation of N2-fixation in chickpea by gamma irradiation as affected by different levels of ammonium sulfate fertilizer

Kurdali, F.; Al-Shamma, M.; Ayyoubi, Z.

Stimulation of N2-fixation in chickpea by gamma irradiation as affected by different levels of ammonium sulfate fertilizer

2000

Kurdali, F. | Al-Shamma, M. | Ayyoubi, Z.

A pot experiment was conducted under natural climatic conditions to study the effect of low doses of gamma irradiation (0, 5, 20, and 20 Gy) on the performance of winter chickpea (Cicer arietinum L.) in the presence of increased supply of 15N labeled ammonium sulfate (2, 20, 50 and 100 kg N ha-1). Presowing seed irradiation produced a significant increase in dry matter production (up to 36%) and total nitrogen yield (up to 45%). The stimulative effect of irradiation was more pronounced with the application of NH4(+)-N fertilizer. Seed irradiation increased the amount of N2-fixation by 8-61% depending on the dose and level of NH4(+)-N fertilizer rate. A 10 Gy was found to be the optimal irradiation dose for enhancing N2-fixation. High levels of NH4(+)-N decreased the percentage and the amount of N2-fixation, but did not affect nodule formation. However, the presowing 10 Gy irradiation dose reduced the negative effect of ammonia-N fertilizer on N2-fixation. Therefore, we recommend irradiating chickpea seeds with a 10 Gy dose before planting in soil containing high levels of mineral nitrogen to reduce its negative effect on N2-fixation.

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