Effect of Drought Stress, Plant Density and Harvesting Satge on Forage Yield and Quality of Kochia (Kochia scoparia L.)

In recent years shortage of water and necessity of forage production have led to a tendency towards low-input plants such as Kochia. Kochia, that plant that, in addition to drought and salinity tolerance, have the potential to produce forage in less favorable environmental conditions. To evaluate forage yield and quality of Kochia as affected by drought stress, plant density and harvesting stage a field experiment was conducted in 2020 and 2021 at the Jupar agricultural research rtation of Kerman. The experiment was carried out as split plot factorial arrangements in randomized complete block design with three replications. Drought stress at three levels; irrigation at 50%, 70% and 90% depletion of soil available moisture were assigned to main plots and two planting density; 33.3 and 16.6 plant m-2 and two harvesting stages; vegetative growth stage (55 days after emergence) and flowering stage as factorial were randomized in sub plots. In irrigation at 50% and 90% soil available moisture depletion dry forage yield was 7.15 and 6.45 ton ha-1, respectively, however, this difference was not significant. Harvesting at the flowering stage with production of 31.30 ton ha-1 of fresh forage and 8.96 ton ha-1 of dry forage was significantly superior in comparison with other treatments. The highest amount of forage protein (10.94%), and the lowest amount of NDF (%50.6) and ADF (%33.8) were obtained in the severe drought stress (90% depletion of soil available moisture). Harvesting at the flowering stage had lower protein and higher NDF than vegetative growth stage. The results of this study indicated that it is possible to produce 4.5 ton ha-1 of dry forage by harvesting at vegetative growth stage and 8.5 t ha-1 of dry forage at the flowering stage by application of irrigation at 70% to 90% soil available moisture depletion.