Comparative Study of the Effects of Corn Wastes and Poultry Dropping Composts with Inorganic Fertilizer on Soil N and P Mineralization, PH and Microbial Activities under Laboratory Conditions.

Abstract

The comparative effects of corn waste and poultry droppings composts with inorganic fertilizer on N and P mineralization, pH and microbial activities in soil were assessed in a laboratory incubation study with a view of studying the effectiveness of corn waste compost as amendment for a degraded soil. The study was conducted in the Soil Microbiology Laboratory, Department of Soil Science and Land Resources Management, Obafemi Awolowo University, Ile-Ife, Nigeria. The experiment was arranged in a Completely Randomized Design (CRD) with 3 replicates. The treatments were: control, three corn waste composts (corn waste boiled with salt, corn wastes boiled with water alone, corn waste not boiled all), poultry droppings compost and inorganic fertilizer (N.P.K. 20:10:10). The composts were added at the rate of 5t/ha while the NPK was added at the rate of 25 kg N/ha. Mineralized N and P as well as CO2 evolution were assessed in the incubated soil fortnightly over a period of 16 weeks. Soil pH was also evaluated at the end of the incubation period. Corn wastes and poultry dropping composts increased N and P contents over the control throughout the period of incubation, with the highest values obtained in the unboiled corn waste compost, with values of 2.53 and 151.56 mg/kg, respectively. Corn wastes and poultry droppings composts improved soil pH and increased microbial activities in the soil over the control throughout the period of incubation with the highest values observed in corn waste compostthatwasnotboiled(F3)whichgave71.1mgC/100g.Applicationof unboiledcornwastecompost(F3) givingthehighestcontentforNandPnutrientsisthereforerecommended.. Italsorecommendedasitgavethe highest pH though all the composts had liming effects as against inorganic fertilizer that showed acidifying capacity. Microbial activities was highest at 4th week of incubation as maximum CO2 evolution was observed at that time for all the compost incubation. Application of corn waste composts without any major heat treatment could therefore be recommended for soil fertility parameters improvement rather than leaving them on the farm to constitute environmental hazard.