THE EFFECT OF MULCHING PERCENTAGE AND WATERING FREQUENCY ON Grevillea robusta SEEDLING PRODUCTION: IN THE CASE OF KELEM MEDA NURSERY SITE, SOUTH WOLLO ZONE, ETHIOPIA

Grevillea robusta is recognized by the pinnate and deeply lobed fernlike leaves, dark green adaxial, silky with whitish, by showy yellowish flowers clustered on and by black curved pod. Techniques of seed dormancy avoidance were written for different species by different authors. However, a combined effect of watering frequency and germination percentage for successful germination of G. robusta seed is scantly documented. Therefore, this study was conducted with the aim of evaluating the effect of mulching and watering frequency on seed germination, height and leaf number. The research design was factorial experiment in the arrangement of eight different treatments with three replications. The plot size was 1m by 1m and the spacing between plot and block were 0.4m and 1m respectively. The frequency of watering (w) and mulching (M) percentage results variation in height and germination percentage. M0% with watering in one day gap (w1), M0% with watering all day (wa), mulching above 75% and no mulching generally delay total germination percentages of seedling. The optimum mulching (%) and frequency of water for rate of normal seed germination was between mulching M25% wa to M50% wa. The optimum mulching and frequency of water for seedling height was attended at M50% wa. Therefore, the germination responses of seed of G. robusta vary as per mulching percentage and watering frequency it has. Further study on how mulching and watering frequency improve the soil microbial activity and temperature during seed germination of G. robusta species on the seedbed across Agroecology is needed.