NITROGEN DYNAMICS AND NITROGEN USE EFFICIENCY WITH NEEM COATED UREA IN RICE CULTIVATION
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Date
2017
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Acharya N.G. Ranga Agricultural University
Abstract
A field experiment entitled “Nitrogen dynamics and nitrogen use
efficiency with neem coated urea in rice cultivation” was conducted at
Agricultural College Farm, Bapatla during kharif, 2016. The experimental soil
was clay in texture, slightly alkaline in reaction and non-saline. The soil was
medium in organic carbon and available nitrogen, high in available phosphorus
and potassium and sufficient in sulphur. The soil was high in zinc, copper,
manganese and iron.
The experiment was laid out in RBD with nine treatments replicated thrice.
The treatments comprised of T1- Control, T2-100% RDN through urea in 3 split
doses, T3 - 75% RDN through neem coated urea in 3 split doses, T4 - 100% RDN
through neem coated urea in 3 split doses, T5-125% RDN through neem coated
urea in 3 split doses, T6-100% RDN through urea in 2 split doses, T7-75% RDN
through neem coated urea in 2 split doses, T8-100% RDN through neem coated
urea in 2 split doses, T9-125% RDN through neem coated urea in 2 split doses.
Well decomposed farmyard manure @ 10 t ha-1
was applied to the field as
per recommended dose ten days before transplanting. The inorganic nitrogen
through urea and neem coated urea was applied in 3 splits (as basal and at tillering
and panicle initiation stages) to four treatments i.e T2 to T5 and applied in 2 splits
(as basal and in between tillering and panicle initiation stages) to four treatments
i.e T6 to T9. Entire quantity of P2O5 in the form of SSP and K2O in the form of
MOP were applied to all the treatments as basal dose at the time of transplanting.
(Recommended dose of fertilizers was 120-60-40 kg NPK kg ha-1
).
The influence of various treatments on growth parameters, yield attributes,
yield, soil properties (physical, physico-chemical properties and available
nutrients), nutrient contents and uptake at different stages and forms of nitrogen at
every three days and one week after application of fertilizers were determined by
standard procedures.
All growth parameters, productive tillers m-2
, filled grains per panicle,
grain and straw yield were markedly influenced by the application of neem coated
urea. Maximum grain yield was recorded with 125%RDN through neem coated
urea in three split, which is on par with 100%RDN and 75%RDN through neem
coated urea. The maximum nitrogen use efficiency and apparent N recovery was
recorded in treatment 75% RDN through neem coated urea in 3 splits, while grain
yield is on par with 125% RDN through neem coated urea.
The soil properties viz., bulk density, pH, EC and organic carbon and
micronutrients were not markedly influenced by the imposed treatments. There
was a significant influence of the treatments on available nitrogen and
phosphorus, but not on potassium. The available nitrogen and phosphorus
contents were markedly influenced by the application of neem coated urea at all
the crop growth stages.
The nitrogen content of rice plants at all growth stages was markedly
influenced by the treatments with highest N recorded in treatment supplied with
125% RDN through neem coated urea in three spits. The effect of treatments on
other nutrients in plants was non-significant.
The uptake of N, P, K, S and micro nutrients at all growth stages was
markedly influenced by the treatments with higher values recorded with 125%
recommended dose of neem coated urea in three spits which was at par with 100%
RDN through urea applied in three and two splits.
Application of neem coated urea showed significant influence on forms of
nitrogen. Neem coated urea proved to be more efficient in maintaining the
maximum amount of ammoniacal – N, total nitrogen and mineralizable – N and
lower amount of nitrate – N than urea and control where no nitrogen was applied.
Description
D5452
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