CD Tesis
Pengaruh NBPT-DCD (Penghambat Urease Dan Nitrifikasi) Terhadap Kehilangan Nitrogen, Aktivitas Fisiologis Dan Hasil Kelapa Sawit (Elaeis Guineensis Jacq.) Pada Typic Dystrudepts
Typic Dystrudept is widely used for oil palm plantations. However, Typic
Dystrudept is classified as soil with low fertility, so it is necessary to improve the
chemical properties of the soil with fertilization. Currently, fertilizer prices have
increased quite sharply and the level of fertilizer efficiency is still low, so efforts
need to be made to increase fertilizer efficiency. Nitrogen is one of the primary
macronutrients for palm oil commodities. However, its presence in the soil is quite
mobile, so it is easily lost through washing or evaporation and also binds to
compounds that are not available to plants. The large potential for N loss in the soil
requires efforts to reduce this loss. One way to suppress N loss is to inhibit urease
activity and the nitrification process using inhibitors. These inhibitors include
NBPT (urease inhibitor) and DCD (nitrification inhibitor).
The experiment was carried out in January 2021–December 2021 at an oil
palm plantation in Kubang Jaya Village, Kampar. The research aims to analyze N
loss, N uptake, physiological activity and yield of oil palm when using NBPT and
DCD.
The field experiment used a single factor Completely Randomized Design
(CRD) with three replications. The treatment tested was a nitrogen (N) fertilization
package, consisting of 5 treatments, namely N0 urea dose 100% (2.75
kg/palm/year), N1 Urea dose 80% + NBPT-DCD (2.20 kg/palm/year), N2 Urea
60% dose + NBPT-DCD (1.65 kg/palm/year), N3 Urea 80% dose (2.20
kg/palm/year) and N4 Urea 60% dose (1.65 kg/palm/year). The observations made
were environmental conditions, soil analysis variables, vegetative analysis
variables (leaf area index), plant tissue analysis, physiological component analysis
(chlorophyll, photosynthesis rate, transpiration rate, stomatal conductivity and
CO2 concentration in cells), NH3 loss analysis, Analysis of yields and components
of palm oil products (production of fresh fruit bunches, analysis of bunches and
oil). Data analysis was analyzed using analysis of variance (ANOVA) at the 5%
level, then continued with the 5% DMRT further test.
The research results provide information that the use of urea in combination
with NBPT-DCD (urease and nitrification inhibitor) is able to reduce 30.33-
37.48% loss and increase N uptake compared to urea without the NBPT-DCD
combination. Oil palm plants on Typic Dystrudept soil that were applied with a
dose of 80% urea (2.20 kg/palm) combined with NBPT-DCD were able to reduce
N evaporation and increase N uptake, and production was the same as treatment
with a dose of 100% (2.75 kg/palm). So it is more efficient and effective to fertilize
urea on oil palm plants, but the physiological components have not shown the effect
of treatment.
Key words: Typic Dystrudepts, urea (N) fertilizer, NBPT-DCD, and palm oil
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