Abstract:
Phosphate sorption studies was carried out at the University of Agriculture Makurdi to determine
the influence of poultry manure on Phosphorus sorption in some Alfisols of Benue State. Surface
soil samples (0 - 20 cm) were collected from three different locations in Benue State (Daudu,
TseKough and Ayange) and Poultry manure sourced from the University of Agriculture Makurdi
Livestock Teaching and Research Farm. The physical and chemical properties of the soils and
poultry manure were determined using standard procedures. Phosphate sorption characteristics of
the soils and the influence of poultry manure was determined by equilibrating 5 g sub samples of
2 mm sieved soils from each location in two sets of 60 cm3
sample bottles. Volumes of 40 cm3
of
0.01 M CaCl2 solution containing 0, 15, 25, 40, 100, 200, 400, and 800 mg l-1P as K2HPO4 were
distributed to each set of the sample bottles. Poultry Manure was added to one set at the rate of 6
t ha-1
(11.85 g) and the other set left without poultry manure and the soils incubated for 6 weeks
after which the samples were equilibrated. The supernatant was filtered and P in the solution
analyzed by the modified method of Murphy and Riley. The Freundlich adsorption equation was
used to evaluate the adsorption data. Results indicate that the adsorption capacities of the soils
were 35.58 mg kg-1
for Daudu, 35.43 mg kg-1
for TseKough and 33.12 mg kg-1
for Ayange.
Addition of poultry manure however, reduced the adsorption capacities of the soils to 33.10 mg
kg-1
, 34.26 mg kg-1
and 33.00 mg kg-1
representing 6.97 % decrease for Daudu soil, 3.36 % for
TseKough and 0.36 % for Ayange. The phosphorus buffering capacities (PBC) of the soils
ranged from 115.26 mg kg-1
at Tse-Kough, 126.33 mg kg-1 at Ayange to 130.28 mg kg-1
at
Daudu. Upon addition of Poultry manure, PBC increased to 126.28 mgkg-1
,137.85 mg kg-1
and
133.65 mg kg-1
for Tse-kough Ayange and Daudu respectively. It was concluded that addition
of poultry manure would increase the phosphate buffering and reduce the adsorption capacities
of the soils. |
