Phytotoxicity assessment of compost-type Biofertilizer using Co-Composting and Post Composting Fortification Methods

Phytotoxicity sets in when immature and not well prepared compost is used on the farm. This research work was targeted at preparing compost from different organic material combination and assessing the phytotoxic effects of different compost combinations. Compost of organic materials was prepared and fortified giving the following combinations: PM+RB+BM+GL, PM+SD+BM+GL, PM+RB+GL and PM+SD+GL. The carbon and nitrogen sources were combined using 1:3 ratio, the combination was sprinkled with water. Data such as ambient temperature of each pile was taken daily, while pH and electrical conductivity tests were taken on samples fortnightly. On maturation of the compost, post fortification technique was carried out hereby creating two more combinations tagged PM+RB+GL (BMP) and PM+SD+GL (BMP). The six compost combinations were tested in terms of their germination percentage, after which data on germination %, relative germination %, root length, weight gained and germination index were taken and analyzed using anova, their mean were separated using Duncan Multiple Range Test (DMRT) at 5% probability level.Fortification with phosphorus source at the onset of composting promoted plant growth hence no sign of phytotoxicity while fortification with phosphorus source after maturation increased phytotoxicity. (SD = Sawdust, RB = Rice bran, GL = Glyricidia sepium and BM = Bone meal).