- Solid waste is a big issue to many countries. Energy problem, is also a critical issue with the declining of the useable fossil-fuels and world is now moving toword the reniverble ennergy. Feeding the ever increasing world population through sustainable crop cultivation is a challenge and biogas units give great solutions for them. Biogas slurry is a by-product of biogas production, containing abundant nutrients, so this may be good for use as a fertilizer or same times as organic fertilizer. Biogas effluent (slurry) is lower in pollution potential, has less odor, contains fewer viable weed seeds, has fewer pathogens than the input and is an excellent bio-fertilizer. But still not much information are available on biogas slurry use as fertilizer in Sri Lankan condition, so research was forcused to find out the way to use biogas slurry as a fertilizer, in effective and efficant manner. Different type of biogas slurry (AKitchen waste slurry, B- Cow dung slurry, C- Herbal waste slurry, D-Hotel waste slurry and E- Recommended fertilizer mixture) was applied to Bush Bean (“Phaseolus vulgaris”) plants and observe crop growth and yield differentiations. Slurry application methods were changed (B-bulk application, S-Split application, LLiquid fertilizer spray weekly) to discover the differentiations in performance. Randomize Complete Blog Designing (RCBD) was employed to carry out field experiment. Shoot-length, Root-length, Leaf area, Shoot dry weigh, Root dry weigh, Leaf dry weigh were measured. Two Factor Factorial model and Analysis of variance (ANOVA) are used for the analysis. Crop growth are significantly different to each other according to the, Shoot length (P=0.001), Root length (P=0.002) and Shoot dry weigh (P=0.00) considering the 95% confident interval. Even though shoot length, root length, and shoot dry weigh change with time those parameter are not significantly varied with the subTreatment (P=0.84, 0.664 and 0.68). Root dry weigh (P=0.01), Leaf dry weigh (P=0.00), Shoot to root ratio (P=0.00) and Leaf area (P=0.00) also significantly change with the slurry type but only the shoot to root ratio is significantly affected (p=0.03) by the slurry application method. Type of biogas slurry significantly affects to the crop growth. Cow dong slurry can replace the recommended fertilizer mixture effectively and Hotel waste slurry also capable of replacing the inorganic fertilizer to some extent. But Herbal waste slurry is week in this parameter. Slurry application method does not significantly affect to the all most all parameters excluding shoot to root ratio. Even though there are not much prominent different with application methods still Bulk application and Split application methods are superior to liquid (spring) application. Most suitable method is Bulk application method.

Keywords : Biogas-slurry, Organic-Fertilizer, Solid waste management. Crop growth, Phaseolus vulgaris.