Studies on Potassium Dynamics and Fertigation Scheduling for Kinnow
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Date
2011
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Publisher
IARI, Division of Agricultural Engineering
Abstract
Kinnow (Citrus reticulata Blanco), a hybrid of King and Willow leaf mandarin,
is a rich source of Vit-C and commercially important fruit crop in India. The cultivar
holds a unique position among all varieties of citrus due to its economic earnings in the
country. In recent years Kinnow has become the most favourable cultivar among citrus
growers in Northern India and at the same time drip irrigation has gained popularity
among the citrus growers. However citrus growers are unaware about the quantity of
water and fertilizers to be applied to citrus crops at different growth stages under drip
fertigation. Field experiments were carried out at the farm of Centre for protected
cultivation Technology, Indian Agricultural Research Institute, New Delhi during 2010
and 2011 to study the effect of different levels of fertigation on fruit yield and quality
parameter of kinnow and dynamics of water and potassium under drip fertigation using
Hydrus 2D model. The experiment consisted of nine treatments with three levels of
irrigation amount i.e 60, 80 and 100% of ETc and three levels of potassium fertilizer i.e
600 g K/plant/year (F1), 700 g K/plant/year (F2) and 800 g K/plant/year (F3). The
maximum yield (32.67 t/ha) was observed at 80% of ETc and 700 g/plant/year K
followed by 100% of ETc and 800 g/plant/year K (32.18 t/ha). Minimum yield was
obtained with 60% of ETc and 600 g/plant/year K (19.79 t/ha).The maximum TSS
(12.03 %) and fruit juice content (46.8%) were found under 80% of ETc and 700
g/plant/year K and 100% of ETc and 800 g/plant/year K treatments and minimum under
60% of ETc and 700 g K/plant/year and 60% of ETc and 800 g plant/year K treatment
respectively. The treatments with 60% ETc were different from 80 and 100%, however
80% and 100% ETc treatments had same effect on yield, TSS and juice content. Water
and potassium dynamics in the root zone of kinnow crop were simulated for T5 (80%
ETc and 800 g/plant/year K) treatment as highest yield was obtained under this
treatment. The field data for observed water content and potassium were collected at
24, 48 and 72 h after fertigation to calibrate the Hydrus 2D model. The simulation
results for sandy loam soil showed that moisture content in the active root zone was near
to field capacity at 24 and 48 hrs after irrigation but there was decline in moisture
content after 72 hrs. The irrigation frequency was 72 hrs which indicated that moisture
was readily available in the active root zone of the kinnow plants and was ideal for
healthy crop growth. Potassium concentration at 24, 48 and 72 h after fertigation was
found higher in upper layer of soil (15-30 cm) and lower in deeper layer (45-60 cm).
From the simulation studies it was revealed that 4 lph dripper optimised the potassium
concentration between depth of 15-30 cm. So results clearly indicated that potassium
was efficiently utilized with 4 lph dripper, as the active root zone (highest root density)
of the kinnow was found between 15-30 cm depth. Results indicated that 4 lph dripper
was the optimum discharge size for potassium fertigation in sandy loam soils. Based on
the experiment conducted to study the effect of different levels of Fertigation on fruit
yield and quality parameters, the treatment with 80% ETc and 700 g K/plant/year of was
chosen as optimum dosage to increase the yield and quality of kinnow fruits. This study
helped in choosing the optimum dosage of water and fertilizer which was used for
developing an optimal fertigation schedule for kinnow plants. The fertigation schedule
involved month wise application of number of irrigations and application of the
fertilizer dosage based on different crop growth stages of kinnow
Description
T-8444
Keywords
irrigation, fertigation, fruits, potassium, yields, fertilizers, crops, nutrients, trickle irrigation, marketing