MSc

Nano nitrogen application in papaya (Carica papaya L.) for growth,
yield and quality enhancement
The study entitled “Nano nitrogen application in papaya (Carica papaya L.)
for growth, yield and quality enhancement” was conducted in the Department of Fruit
Science, College of Agriculture Vellayani, from 2022 April to 2023 June. Nitrogen
plays a major role within the plant to ensure energy is available when and where the
plant needs it to optimize yield. The present work was undertaken to assess the effect
of foliar applied nano nitrogen on growth, yield and quality enhancement in papaya.
The field experiment was laid out in Randomized Block Design (RBD) with
10 treatments and 3 replications. The papaya variety Arka Surya was selected for the
experiment purpose. Treatments were T1-POP (25% N) (soil) + Nano N (6 foliar
sprays at 2, 4, 6, 8, 10 and 12 MAP), T2-POP (25% N) (soil) + Nano N (5 foliar
sprays at 2, 4, 6, 8 and 10 MAP), T3-POP (25% N) (soil) + Nano N (4 foliar sprays at
2, 4, 6 and 8 MAP), T4-POP (50% N) (soil) + Nano N (6 foliar sprays at 2, 4, 6, 8, 10
and 12 MAP), T5-POP (50% N) (soil) + Nano N (5 foliar sprays at 2, 4, 6, 8 and 10
MAP), T6-POP (50% N) (soil) + Nano N (4 foliar sprays at 2, 4, 6 and 8 MAP), T7-
POP (75% N) (soil) + Nano N (6 foliar sprays at 2, 4, 6, 8, 10 and 12 MAP), T8-POP
(75% N) (soil) + Nano N (5 foliar sprays at 2, 4, 6, 8 and 10 MAP), T9-POP (75% N)
(soil) + Nano N (4 foliar sprays at 2, 4, 6 and 8 MAP), T10-KAU POP (240:240:480
g NPK plant per year) (control). Foliar application of nano nitrogen was given @ 4ml
per litre and FYM was applied at the rate of 10kg per plant as per KAU POP
uniformly to all treatments as basal dose. The requirement of lime, phosphorus and
potassium were met on the basis of calculated value as per initial soil status.
Application of 75% nitrogen through soil along with 6 foliar sprays nano
nitrogen (2, 4, 6, 8, 10 and 12 MAP) in bimonthly interval increased the biometric
characters like height of plants, girth of plants, number of leaves, number of flowers
per cluster, number of female flowers, fruit set and decreased height at first flowering,
days taken for first flowering, and flowering to harvest duration.
The results reveals that yield characters such as fruit weight, fruit length, fruit
girth, fruit volume, pulp percentage, flesh thickness, number of fruits per plant and
total yield per plant was increased and days taken for maturity of fruit was decreased
while application of 75% nitrogen through soil along with 6 foliar sprays of nano
nitrogen (2, 4, 6, 8, 10 and 12 MAP).
Each character among the qualitative ones examined varied significantly.
Application of 75% nitrogen through soil along with 6 foliar sprays of nano nitrogen
(2, 4, 6, 8, 10 and 12 MAP) reduced the titrable acidity and recorded maximum TSS,
total sugar, reducing sugar, ascorbic acid, carotenoid whereas plants treated with 25%
nitrogen through soil along with 4 foliar sprays nano nitrogen (2, 4, 6 and 8 MAP)
reported the lowest values for these characters. Pulp and peel color also improved in
this (T7) treatment.
Application of 75% nitrogen through soil along with 6 foliar sprays nano
nitrogen (2, 4, 6, 8, 10 and 12 MAP) increased the organoleptic qualities like
appearance, colour, taste, flavour and overall acceptability. Shelf life of fruits were
longer with the same treatment.
According to data on the soil analysis there was a reduction in soil available
nitrogen and in plant analysis, nitrogen, phosphorous, potassium,content was the
highest with the plants treated with 75% nitrogen through soil along with 6 foliar
sprays nano nitrogen (2, 4, 6, 8, 10 and 12 MAP). Similarly data on fruit analysis
showed that nitrogen, phosphorous, potassium content was the highest with the T7.
The Foot rot caused by Phytophthora palmivora was noticed in the field with
less than 1 per cent incidence rate. Also red spider mite infestation was noticed in
some plants. The pest and disease incidence were controlled by taking appropriate
remedial measures as and when noticed.
The highest net income and benefit cost ratio was observed while applying
75% nitrogen through soil along with 6 foliar sprays nano nitrogen (2, 4, 6, 8, 10 and
12 MAP) followed by plants that treated with Ad hoc recommendation (240:240:480
g NPK plant per year).
From the above findings, it was concluded that application of 75% nitrogen
through soil along with 6 times foliar sprays of nano nitrogen (2, 4, 6, 8, 10 and 12
MAP) along with the application of organic manure (10 kg FYM plant-1
) increased
the growth, yield and quality characteristics of papaya and it was economically viable
too