Influence of water source and irrigation system on charcoal rot of sunflower plants

Abstract

The scarcity of arable water is a worldwide challenge. Charcoal rot is an important disease for sunflower plants, a crucial oil crop in Egypt and globally. Field experiments were conducted in Ismailia Governorate, Egypt during the 2020 and 2021 growing seasons in soil naturally infested with Macrophomina phaseolina to study the effect of water source and irrigation systems on charcoal rot development on sunflower plants. River Nil (non-sodic containing 0.84 meq sodium/ L), deep-well (sodic containing 59 meq sodium/L), and surface and drip irrigation were used. The incidence of charcoal rot was increased under well water and drip irrigation more than river water or surface irrigation. Infection increased from 27.5 to 27.3% with river water via surface irrigation to 37.4 and 38.2% with well water via drip irrigation in the first and second seasons respectively. Nitrogen concentration in sunflower leaves was not influenced by water source or irrigation system, while P and K decreased from15.1, 15.4, 24.3 and 24 mg/ gm with river water to13.1, 13.5, 13.3 and 14.3 mg/ gm with well water when surface irrigation used in the first and second season. Seed yield and oil concentration decreased from 43.1 to 44.7 kg seed/ plot; and 57.4 and 47.5% seed oil with river water to 37.4 and 35.8 kg seed/ plot; and 43.6 and 38.2% seed oil with well water via surface irrigation in first and second season.Well water increased sodium accumulation in the soil compared to river water from 1.49 to 1.74 kg/ hectare. Irrigation system did not affect sodium content when river water used, while with well water, drip irrigation increased sodium content more than surface irrigation. Consequently, water quality and irrigation systems affect sunflower plants’ growth, charcoal rot incidence, and may increase sodium accumulation in soil.