TITLE:
Effect of Effluent from Biodigestion of Pre-Treated Rice Bran and Animal Manure on the Dry Matter Yield and Nutrient Uptake of Amaranthus viridis
AUTHORS:
Oluwakemi Florence Ojo, Gbolabo Abidemi Ogunwande, Olusola Olajumoke Adesanwo, Francis Tope Olatoberu
KEYWORDS:
Biogas, Rice Bran, Animal Manure, Effluents, Yield, Nutrient Uptake
JOURNAL NAME:
Food and Nutrition Sciences,
Vol.12 No.12,
December
23,
2021
ABSTRACT: The effect of effluents from biodigestion of pre-treated
rice bran in combination with two types of animal manure on dry matter yield of Amarathus viridis was investigated using two pre-treatment methods: Soaking in ordinary distilled
water and boiled in distilled water at 100°C. The pre-treated rice bran and
animal manure were mixed (w/w basis) to give carbon to nitrogen ratio of 35:1
and 37:1 prior to loading into the digester to make eight different treatment
combinations as follow: 1) Cow dung with no rice bran (NRB + CD); 2) Raw rice
bran + cow dung (RRB + CD); 3) Soaked rice bran in ordinary distilled water +
cow dung (SRB + CD); 4) Boiled rice bran + cow dung (BRB + CD); 5) Poultry manure
with no rice bran (NRB + PM); 6) Raw rice bran + poultry manure (RRB + PM); 7) Soaked
rice bran + poultry manure (SRB + PM); 8) Boiled rice bran + poultry manure
(BRB + PM). Samples of different treatment combinations were collected before
digestion, both the samples and resultant effluents were subjected to elemental
analysis using AAS. The effluents from the biodigestion of these combinations
were applied at two rates (80 and 150 kg N ha-1) to 3 kg air-dried
and sieved soil samples (0 - 20) cm in the greenhouse, control (0 kg N ha-1)
and reference pot with NPK fertilizer at the 80 kg N ha-1 were
arranged in a completely randomized design replicated three times. Amaranthus
plants were introduced into each treated pot, left for four weeks before
harvest, dry matter yields were recorded. Results of chemical analysis of raw
materials and effluents obtained after biodigestion revealed the presence of all plant nutrients in both the raw
materials and resultant effluents though the former had higher values in
some nutrients than the effluent, for examples treatment combination of CD, the
values for organic carbon (42.85%), Ca (3.41%) and Mg (0.61%) were higher than
in the resultant effluent for CD, a similar trend was observed with other
treatment combinations. Drastic reduction in heavy metal concentration was
observed after digestion, Pb content in the raw materials for poultry manure
reduced by 94.7% in the resultant effluent from BRB: PM thus making the
effluent a better soil amendment. Raw chicken manure was richer in the
nutrients needed for optimal crop growth however, raw cow dung had the highest.
The amendment of effluent from boiled rice bran with poultry manure at 150 kg N
ha-1 significantly increased the dry matter yield of Amaranthus viridis over control pots,
NPK pots and all other amendments thus making it a good alternative to NPK
fertilizer.