Effect of drought stress and different levels of potassium on quantitative and qualitative forage yield of Kochia (Kochia scoparia L.)

In order to study the effect of potassium fertilizer under drought stress conditions on growth and forage quality of kochia (Kochia scoparia L.) a field experiment was conducted in split plot design based on complete randomized block with three replications at the Institute of Agricultural Research, University of Zabol, in 2011. The main plots were included three irrigation levels as follows irrigation after 50 percentage depletion of soil water (I1, control), irrigation after 70 percentage depletion of soil water (I2) and irrigation after 90 percentage depletion of soil water (I3), and sub plots were included four levels of potassium fertilizers (control, 75, 150 and 225 kg.ha potassium sulfate). The results showed that drought stress reduced fresh and dry weight, plant height, dry matter digestibility, crude protein and increased water soluble carbohydrate forage. The potassium fertilizer, increased fresh and dry weight, plant height, dry matter digestibility forage, but both treatments had no effect on number of branches. The maximum amount of fresh and dry weight, plant height, dry matter digestibility, water soluble carbohydrate and number of secondary branches forage obtained from treatment with application 225 kg.ha potassium fertilizer. The interaction of experimental factors on all traits was significant except on number of secondary branches. In general, the results of this experiment showed that the highest quantitative and qualitative forage yield obtained from irrigation after 50 percentage depletion of soil water (control) and application of 225 kg.ha potassium fertilizer.