Effect of crude and composted olive cake as organic manures on growth of corn plants grown on a sandy soil

الملخص EN

A greenhouse pot experiment was conducted using a light texture soil as growth media for corn plants (Zea maize) variety Giza-2 grown for 90 days to evaluate olive cake waste as organic manure.

Soil samples were taken from rhizosphere area at periods of 0, 60 and 90 days from cultivation to identify influence of phenolic compounds containing crude olive cake on microflora.

The main results can be summarized as follows: The dry matter yield of corn plants was pronouncedly increased due to addition of all treatments compared to the control treatment, > except for the treatment of crude olive cake.

The percentages of increase in dry weight of corn plants grown for periods of 60 and 90 days from seedling were 37.4% and 29.8%, respectively.

On contrary, the dry weight was decreased by percentages of 4.5% and 8.15%, due to addition of crude olive cake, at the same periods, respectively.

The concentrations of N, P and K in corn plants increased due to all treatments.

Except the treatment of crude olive cake which negatively effected N, P and K concentrations in corn plants as compared with the corresponding ones of the control treatment.

Total counts of bacteria, actinomycets and fungi were significantly affected with growth periods and different treatments as well as the interaction between them.

However, the treatment of crude olive cake decreased the microflora population density at growth periods of 0, 60 and 90 days.

The concentrations of total and free phenols in corn plants were significantly affected with all treatments.

High concentrations of phenolic compounds in corn plants were obtained due to application of the crude olive cake.

On the contrary, corresponding lowest values were achieved due to application of the composted olive cake.

Keywords: Total phenols, free phenols, NPK, rhizosphere, corn plants, dry weight, organic fertilizers.