Co-application of biochar and urea to improve nutrient use efficiency and yield of Oryza sativa L. in tropical acid soil
Excessive use of nitrogen (N) fertilizer in sustaining high rice yields due N dynamics in tropical acid soils has necessitated the exploitation of nutrients addition and retention properties of organic amendment such as chicken litter biochar to increase lowland rice yield and to also reduce N fe...
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| Format: | Thesis |
| Language: | English |
| Published: |
2015
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/78353/1/FSPM%202015%204%20ir.pdf |
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| Summary: | Excessive use of nitrogen (N) fertilizer in sustaining high rice yields due N dynamics in
tropical acid soils has necessitated the exploitation of nutrients addition and retention
properties of organic amendment such as chicken litter biochar to increase lowland rice
yield and to also reduce N fertilization by improving soil nutrients availability and plant
nutrients use efficiency. Biochar (5 t ha-1) and different rates of urea (100%, 75%, 50%,
25% and 0%) only were evaluated in pot and field trials. Selected soil and rice plants
physicochemical properties were analyzed using standard procedures. Dielectric
response of the soil samples at 20, 40, 55, and 75 days after transplanting of rice plants
were determined using an inductance-capacitance-resistance meter HIOKI 3522-50 LCR
HiTESTER.
Soil nutrients availability, plants nutrients uptake, nutrients use efficiency, crop recovery
and agronomic efficiency of applied N, and dry matter yield in the pot and field trials
were significantly increased due to co-application of urea with biochar. This was
confirmed by the magnitude, shape, and pattern of spectral response of dielectric
conductivity and permitivity. Biochar and N rates stimulated the availability of other
nutrients especially available P and K. Grain yield of co-application of biochar with 75%
urea of the first and second cycles (7.56 t ha-1 and 9.06 t ha-1) were 44.31% and 44.37%,
respectively, higher than that of recommended fertilization (4.21 t ha-1 and 5.04 t ha-1).
However, the grain yield of co-application of biochar with 100% urea and co-application
of biochar with 75% urea in the field trials were not significantly different although coapplication
of biochar with 100% urea had 25% more N fertilization than that of coapplication
of biochar with 75% urea indicating that, biochar can be used to improve
grain yield and as well as reducing N fertilization in rice cultivation on tropical acid soils.
Yield of co-application of biochar with 75% urea was higher due to the differences in
number of panicles as a result of the effect of biochar on nutrient availability and N use
efficiency.
Dielectric conductivity and permitivity of soil samples measured before transplanting
rice plants were higher than that of soil samples measured during the cultivation of the
rice plants due to low moisture content of the soil samples. Dielectric conductivity of the
soil samples was dependent on frequency and nutrients concentration in soil solution.
Permitivity of the soil samples was inversely proportional to frequency but directly proportional to N concentration in soil solution. The conductivity measured at 1000 Hz
to 100000 Hz correlated positively with rice grain yield suggesting that dielectric
measurement can be used to estimate rice yield and soil nutrients concentration. This
study may only be applicable to tropical acid soils and will contribute to improvement in
nutrients use efficiency as well as reducing usage of chemical fertilizers. The use of
dielectric technology to measure soil nutrients especially N in rice fields contributes to
efficient application and utilization of chemical fertilizers, however, further studies are
required to establish a stronger correlation between conductivity and N concentration in
rice fields. |
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