Effect of biofertilization and organic manuring on soil dehydrogenase activity, macronutrients and essential oil content of marjoram

Two field experiments were carried out at an organic farm [Minoufia Governorate] during 2005- 2006 and 2006-2007 seasons to study the interaction effect of biofertilization and organic manuring on dehydrogenase, polyphenol oxidase and peroxidase activity, macronutrients uptake, oil yield and oil composition of marjoram. Greater activities of dehydrogenase, peroxidase and polyphenol oxidase were obtained in soil and marjoram treated with combination of biofertilizers and organic manure than soil treated with biofertilizers or organic manure. The greatest activities of peroxidase and polyphenol oxidase were obtained with the treatment of biofertilization combined with full dose of organic manure. Similar results trend was observed with N, P and K uptake because N, P and K uptake by marjoram were greater with dual application of biofertilization and organic manure than other treatments. There is no significant difference between oil yield obtained with chemical fertilization treatment and biofertilizers combined with full dose of organic manure treatment. Fourteen compounds, accounting for more than 97% of the total volatiles components in most marjoram samples were detected and identified. Dual application of organic manure and biofertilization to soil and marjoram produced maximum percent of terpincn-4-ol [the major compound in marjoram oil] compound in marjoram

Interactions between soil C/N ratio and saprophytic microorganisms in alluvial and calcareous soils

Farmyard manure [C: N= 24], town refuse compost [C: N=36] or sewage sludge [C: N=8] was added to alluvial [Clay] and calcareous [clay loam] soil at the rate of 2% W./W. To study their effect on the densities of fungi and aerobic cellulose decomposers in soil and the changes in the soil carbon: nitrogen ratio. The numbers of the fungal colonies appearing on the count plates showed lower densities in the treated samples than the control of alluvial soil and the lowest numbers were observed in the sewage sludge treatment. This was attributed to the competition between the bacterial and fungal population. However, the counts of fungi in calcareous soil treated with organic manures were remarkably higher than those in the control treatment. The counts of aerobic cellulose decomposers were enhanced by the application of organic manures to both tested soils. The C: N ratio of the soils treated with sewage sludge showed the highest values followed by farmyard manure and town refuse compost which showed also higher values than control