Refinement of Existing Soil Test Based NPK Recommendation for Yield Maximization in Irrigated Maize
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Date
2012
Authors
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Journal ISSN
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Publisher
UAS, Dharwad
Abstract
A survey was conducted during May 2010 in maize growing area of zone-III to study
the physico – chemical properties and nutrient status of surface soil samples. Soils were
neutral to alkaline in reaction (PH: 7.60 to 8.50), and non saline (EC: 0.61 to 3.73 dS m-1),
available nitrogen status was low (89.0 to 224.0 kg ha-1), available P2O5 was low to high (5.6
to 119.5 kg ha-1), but available K2O was medium to high (120.0 to 1470.0 kg ha-1). All the
micronutrient cations were above critical limit except iron.
A field experiment was also conducted during kharif 2010 on Vertisol to study the
effect of different levels of fertilizer recommendation based on soil test values on yield of
hybrid maize under irrigation in the farmer’s field at Savadatti village in Northern Dry Zone
(Zone-III) of Karnataka representing predominantly low–high–high (LHH) fertility status
with respect to N (171 kg ha-1), P2O5 (69.2 kg ha-1) and K2O (367 kg ha-1) respectively.
The experiment consisted of six treatments with four replications having different
levels of fertilizer recommendation based on soil test values. The STCR dose of NPK
(327:166:201 N, P2O5 and K2O kg ha-1 respectively) recorded highest grain yield which was
on par with modified RDF2
treatment that received 225:37.5:19 N, P2O5 and K2O kg ha-1
,
respectively. The stover yield, weight of 100 grains, number of seeds per row, number of
seed rows per cob, girth of cob and length of cob were maximum in STCR treatment and on
par with modified RDF2. Highest B:C ratio (2.38) was recorded in the treatment having
modified RDF2
(+50% N, -50% K2O and -25% P2O5 of RDF).
The nutrient content in the index leaf (N, P, K, Zn, Fe, Mn, and Cu) was higher with
STCR dose followed by modified RDF2 over rest of the treatments. The (grain + stover)
uptake of N, P, K by maize plant and available of N, P2O5, K2O in soil were also higher under
STCR dose followed by modified RDF2 over rest of the treatments.