Effect Of Nutrient-Rich Alternatives On Quality Of Compost Made From Market Wastes

ABSTRACT

Globally, chemical fertilizers cause serious environmental pollution and health hazards. Studies

have shown that compost, a product of biodegradable organic matter, is not popular among

Nigerian farmers because of its low quality. Improving compost quality is a challenge and

supplementing it with natural fortifiers may be safer than opting for chemical fertilizers. This study

was therefore designed to explore the effect of nutrient-rich alternatives on quality of compost

made from market wastes.

This was an experimental study design, comprising compost preparation, formulation with natural

fortifiers, farm plot experiments and laboratory analyses. Organically Fortified Fertilizers (OFFs)

comprised: Plant-Based (PB), Animal-Based (AB), Rock-Based (RB), Organic-mixture (OMmixture

of PB, AB and RB), Synthetic/ Chemical (SC) while ordinary compost was used as

control. The plot experiment was a simple plot randomised complete block design with three

replicates. The main plots comprised three crops- maize (cereal), soybean (legume) and yam

(tuber) while five different OFFs at three rates of applications- 2.0 tons, 2.5 tons and 3.0 tons per

hectare and control formed subplots. Formulation characteristics [organic-carbon, Total Nitrogen

(TN), phosphorus and potassium] were determined using spectrophotometeric and other standard

methods. Germination index method was used to assess phytotoxicity of OFFs. Values obtained

for phytotoxicity were compared with Thailand Agricultural Commodity and Food Standard of

≥80 for safe OFFs. Effects of OFFs on Agronomic Parameters (APs) [Number of Leaves (NL),

Plant Height (PH), Stem Girth (SG), Leaf Area (LA) and crop yield] were assessed in plot

experiments. Data were analysed using descriptive statistics and ANOVA at p = 0.05.

Chemical analysis of OFFs revealed organic-carbon (%): 33.2±0.0, 38.4±0.2, 27.7±0.1, 34.8±0.0,

28.4±0.2, 32.8±0.21; TN (%): 5.69±0.0, 5.74±0.0, 5.85±0.0, 6.05±0.0, 6.15±0.0, 3.21±0.0,

phosphorus (%):0.3±0.0, 0.5±0.0, 0.2±0.0, 0.8±0.0, 0.2±0.0, 0.7±0.1 and potassium (%): 0.5±0.0,

0.7±0.0, 0.4±0.0, 1.0±0.0, 0.4±0.0, 0.9±0.0 for PB, AB, RB, OM, SC and control respectively. The

control had significantly higher phosphorus and potassium, and lower TKN than any of the

formulations. Values obtained for phyto-toxicity were higher than 80 with exception of SC that

was toxic to soybean at 3.0 tons/Ha (74.2). Specifically, OM and RB for maize [NL (10.0±1.1;

9.2±1.0), PH (23.9±5.4cm; 22.7±3.6cm), SG (2.2±0.4cm; 2.2±0.4cm), LA (2.7±0.1cm2;

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3.4±0.7cm2)]; AB and RB for soybean [NL (20.3±10.1; 15.3±4.5), PH (12.0±3.5cm; 10.8±5.8cm),

SG (0.4±0.1cm; 0.4±0.1 cm), LA (21.0±15.7cm2; 18.7±7.2 cm2)] and RB for yam [PH

(44.0±24.0cm); SG (0.8±0.1cm)] respectively gave the best crops’ performances in APs among all

the formulations and the control. Rate of application of OFFs showed no significant effects on

APs. However, AB at 2.0 tons/ha followed by PB (2.5 tons/ha) gave the highest soybean yield; RB

(2.0 tons/ha) gave the highest maize yield and OM (3.0 tons/ha) gave highest yam tuber yield.

Nutrient-rich materials sourced from animal, plant and rock changed the chemical composition of

compost made from market wastes and yielded better agronomic performances than the synthetic

fertilizer. Fortification of compost with natural materials which are readily available and

environmentally friendly should be promoted among the farmers.