Production of N, P, and K humates from palm oil mill effluent sludge and their effects on corn growth
Substantial loss through ammonia volatilization from surface-applied urea reduces urea-N use efficiency in plant production, pollutes environment and burdens economy. This problem could be minimized through the use of agricultural wastes such as palm oil mill effluent (POME) sludge. POME sludge c...
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| Format: | Thesis |
| Language: | English |
| Published: |
2011
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/77997/1/FSPM%202011%202%20ir.pdf |
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| Summary: | Substantial loss through ammonia volatilization from surface-applied urea reduces
urea-N use efficiency in plant production, pollutes environment and burdens
economy. This problem could be minimized through the use of agricultural wastes
such as palm oil mill effluent (POME) sludge. POME sludge could reduce this
volatilization in view of its acidic nature and high cation exchange capacity (CEC)
present in it the form of humic acids (HA) and fulvic acids (FA). The objectives of
this study were to: (I) Evaluate if N, P and K humates produced from POME sludge
could minimize ammonia volatilization from urea as well as improving retention of
soil exchangeable ammonium and nitrates in laboratory condition and (ii) Evaluate
the effect of N, P, and K humates on soil pH, exchangeable ammonium, available
nitrate; N, P, and K concentrations, their uptake and use efficiency in corn (Zea
mays) cultivation under greenhouse condition. HA and FA were isolated from air-dried POME sludge using 0.5 M KOH and 6 N
H2SO4. Daily ammonia loss was measured for 15 days using a closed-dynamic air
flow system. Ammonia released was estimated using boric acid indicator traps which
were replaced every 24 h and titrated with 0.01 N HCl. Soil samples were evaluated
for pH, exchangeable ammonium and available nitrate. Under greenhouse condition,
formulated fertilizers were applied 10 days after planting (DAP) in each pot
containing 10 kg of soil. Soil and plant samples (stems, leaves and roots) were
sampled at 31 DAP. Soil samples were analyzed for pH, ammonium and nitrate
content. Plant samples were analyzed for dry matter production, N, P, and K
concentrations, N, P, and K uptake, and their use efficiency. From the laboratory
study, Urea-TSP-MOP-HA, Urea-TSP-MOP, urea-FA, Urea-TSP-MOP-FA, Ureaacidified
(HA+FA) and Urea-TSP-MOP-acidified (HA+FA) mixtures significantly
reduced ammonia by 13, 20, 23, 30%, and 100% (of the N added as urea),
respectively. These treatments also caused significant retention of soil exchangeable
ammonium. When the treatments were further tested in a greenhouse, Urea-TSPMOP,
urea-FA, Urea-TSP-MOP-Humin, Urea-TSP-MOP-acidified(HA+FA), Urea-
TSP-MOP-FA and Urea-TSP-MOP-HA mixtures had significant effect on dry matter
production, N, P, and K uptake and use efficiency of the test crop (Zea mays)
compared to urea alone. Urea amended with HA, FA, TSP and MOP minimized
ammonia volatilization, as well as improving soil exchangeable ammonium, and
urea-N use efficiency. It must be stressed that results obtained in the laboratory and
greenhouse experiments may only be applicable to similar acid soils. |
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