CONTENTS

J.Res. ANGRAU 41(2) 42-45, 2013
INTEGRATED EFFECT OF ORGANIC MANURES AND INORGANIC
FERTILIZERS ON SOIL UREASE ACTIVITY AND YIELD OF
MAIZE-SPINACH CROPPING SYSTEM
I. USHA RANI. G. PADMAJA AND P. CHANDRASEKHAR RAO
Department of Soil Science and Agricultural Chemistry
Acharya N.G. Ranga Agricultural University, Rajendranagar, Hyderabad- 500 030
Date of Receipt : 26.11.2012 Date of Acceptance : 20.02.2013
ABSTRACT
A field experiment was conducted on a red sandy loam soil during rabi and summer seasons of 2009-2010
with a view to study the effect of organic manures, inorganic fertilizers and their integration on soil urease activity and
yield of maize (rabi) - spinach (summer)cropping system. Among the different treatments application of 75% RDF +
25% through vermicompost (VC) recorded significantly highest grain and stover yield (52.4, 60.8 q ha -1 ) at harvest
but, on par with 75% RDF + 25% through poultry manure and 75% RDF + 25% through FYM. The spinach crop
responded favourably to the residual and cumulative treatments and the highest fresh leaf yield (14.7 and 12.4 t ha -
1
) was recorded in cumulative and residual treatments. The soil urease enzyme activity at different growth stages of
maize and at final harvest of spinach revealed that there was increase in enzyme activities upto active growth stages
of crops and later showed a decrease. Significantly highest urease activity was found in T 4
(100% VC) with a value
of 246.7, 308.2 and 138.7 ìg of NH 4+
-N released g -1 soil h -1 at vegetative, tasseling and at harvesting stage of maize,
which was on par with T 8
, T 11
,T 12
, T 2
, T 6
and T 10
and was significantly different from other treatments in maize crop. The
cumulative and residual effects of spinach revealed that the urease activity was higher in cumulative than residual
treatments.
INTRODUCTION
Increased use of chemical fertilizers in an
unbalanced manner has created problem of multiple
nutrient deficiencies, diminishing soil fertility and
sustainable crop yields. Hence integration of organic
manures and inorganic fertilizers is imperative for
improving soil health in cropping systems.
The enzyme urease (urea amidohydrolase)
is an important extracellular enzyme which influences
the availability of plant utilizable forms of nitrogen in
soils. Urease is a unique enzyme because it catalyses
the hydrolysis of urea to ammonia (NH 3
) which is
subsequently transformed to ammonium (NH 4+
) and
nitrate (NO 3-
) ions. Nitrogen fertilizer use efficiency
is influenced by the activity of this enzyme, the
determination of urease activity in soils provides a
good index about the ability of soils to hydrolyze urea.
In general, the urease activity increases with increase
in organic carbon in soils.
Keeping in view the significance of integrated
nutrient management for better nitrogen management,
an experiment was conducted to study the effect of
organics, inorganics and their integration on urease
enzyme activity at different growth stages of maize
and at final harvest of spinach in maize-spinach
cropping system.
MATERIALS AND METHODS
A field experiment was conducted on a red
sandy loam soil at College Farm, College of
Agriculture, Rajendranagar, Hyderabad during rabi
and summer seasons of 2009-2010, with maize and
spinach, respectively. Field experiment was laid out
in randomized block design with 12 treatments,
replicated thrice. The treatments include, T 1
(Control),
T 2
(50% RDNF through inorganic fertilizer + 50%
RDNF through vermicompost), T 3
(75% RDNF
through inorganic fertilizer + 25% RDNF through
vermicompost), T 4
(100% RDNF through
vermicompost), T 5
(100% RDNF through inorganic
fertilizer), T 6
(50% RDNF through inorganic fertilizer
+ 50% RDNF through poultry manure), T 7
(75% RDNF
through inorganic fertilizer + 25% RDNF through
poultry manure), T 8
(100% RDNF through poultry
manure), T 9
(50% RDNF through inorganic fertilizer
+ 50% RDNF through farm yard manure), T 10
(75%
RDNF through inorganic fertilizer + 25% RDNF
through farm yard manure), T 11
(100% RDNF through
farm yard manure), and T 12
(25% RDNF through
inorganic fertilizer + 25% RDNF through
email: usha.soilscience@gmail.com
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