Effects of coated urea fertilizers on growth and yield of MR219 rice (Oryza sativa L.)
Urea is widely used as a nitrogen fertilizer. However, the efficiency of urea is generally low due to the rapid hydrolysis which has resulted in the low N uptake and contributed to the hazardous environmental effect. The improvement in urea efficiency can be achieved by coating the urea with sele...
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| Format: | Thesis |
| Language: | English |
| Published: |
2016
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/69985/1/ITMA%202016%2024%20IR.pdf |
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| Summary: | Urea is widely used as a nitrogen fertilizer. However, the efficiency of urea is generally
low due to the rapid hydrolysis which has resulted in the low N uptake and contributed
to the hazardous environmental effect. The improvement in urea efficiency can be
achieved by coating the urea with selected coating materials. The coated fertilizer is
known as a slow release fertilizer which ultimately can reduce fertilizer consumption
and minimize the environmental pollution. Experiments were conducted under
laboratory incubation and glass-house conditions with the following objectives (i) to
determine the losses of nitrogen from urea coated fertilizers via ammonia volatilization
and nitrogen mineralization, (ii) to determine the growth performance and yield of
Oryza sativa (MR219) in response to various dosages of urea coated fertilizers. The
optimization of the rate and the time of N fertilizer application as well as investigation
of different N fertilizer formulation were conducted to determine the effects of these
parameters on growth performance in terms of N release in accordance to the rice plant
requirement. The incubation studies were conducted to investigate nitrogen losses via
ammonia volatilization and mineralization (nitrate leaching). The fertilizers labeled as
uncoated urea (U), sulfur coated urea (SCU), gypsum and sulfur coated urea using
rotating drum (GSCUD). The rates of fertilizer used were 50, 100, and 200 kg N/ha. The
results revealed that sulfur coated urea (SCU) was the best fertilizer since it reduced the
rate of ammonia volatilization followed by GSCU and U. The ammonium and nitrate
accumulations were also studied using the same nitrogen fertilizers including control (no
fertilizer added) at 100 kg N/ha. Coating the urea with either 100% sulfur as in the
commercial SCU or 50:50 ratio of gypsum and sulfur in GSCUD demonstrated the
reduction in urea losses via both ammonia volatilization and nitrate leaching. As much
as 25% reduction in ammonia losses via volatilization was observed using SCU and 14%
using GSCUD. The results from this study also showed that the losses via nitrate in
solution are relatively lower compared to ammonium in solution (4.35 mg/L compared
to 0.73 mg/L). The effects of three fertilizers (Urea, SCU, GSCUD) using five rates (0,
50, 100, 150, 200 kg N/ha) and two times of application (single application at 25 DAT
(Day after Planting) and two times application at 25, and 55 DAT) were evaluated under
glass-house conditions. The plants were harvested at 120 DAT. A glass-house study of first planting showed that fertilizer with a single application at the rate of 100 kg N/ha
showed acceptable plant growth performance in terms of vegetation and yield
parameters particularly for GSCUD fertilizer. Using GSCUD (100 kg N/ha with single
application) resulted in 100 grain weight of 4.21 g/pot compared to the other treatments.
However, as expected two times of application showed higher productivity. Using
GSCUD (two-times; 200 kg N/ha) gave higher plant biomass 65.43 g/pot and markedly
higher in grain yield at 39.52 g/pot. Moreover, the highest level for two-times application
increased the uptake of nitrogen by plant up to 52.55 g/pot for the treatment using
GSCUD. The second planting was also carried out under glass-house condition, to repeat
the earlier glasshouse experiments and adding few other new coated fertilizers. The rate
of application was at 100 kg N/ha, single application. Six different types of fertilizers
were tested, namely U, SCU, GSCUP (gypsum and sulfur coated urea using rotating
pan), GSCUD (gypsum and sulfur coated urea using rotating drum), DCU (dolomite
coated urea), and KCU (kaolinite coated urea). The outcomes showed that the
application of DCU to the crop improved the growth as well as the productivity of the
rice yield. The use of DCU increased the plant biomass to 31.60 g, grain yield at 14.84
g/pot and higher in nitrogen uptake at a 16.36 g/pot. The next best fertilizers were
GSCUD and KCU fertilizer. The grain yield was 13.01 g/pot and 13.31 g/pot, plant
biomass at 34.96g and 24.82g, and nitrogen uptake 14.65 g/pot and 13.83 g/pot,
respectively. |
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