STUDIES ON NUTRIENT MANAGEMENT IN AEROBIC RICE-BASED CROPPING SYSTEMS
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Date
2013
Authors
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ACHARYA N. G. RANGA AGRICULTURAL UNIVERSITY RAJENDRANAGAR, HYDERABAD
Abstract
Investigations entitled “Studies on nutrient management in aerobic
rice-based cropping systems” were carried out for two consecutive years
(2011-2012 and 2012-2013) at S.V.Agricultural College farm (ANGRAU),
Tirupati (Southern Agro-Climatic Zone of Andhra Pradesh). In these
investigations, sunhemp was raised as a preceding crop to aerobic rice
during summer, aerobic rice during kharif and groundnut, maize and
sunflower were raised during rabi.
The first season (summer) study was laid out in randomized block
design without consisting of any treatments, comprising of sunhemp
uniformly for green manuring as preceding crop to aerobic rice. At 45 days
after sowing, sunhemp was incorporated in-situ. In the second season
(kharif), aerobic rice crop was raised in the same undisturbed layout,
replicated four times with five graded nutrient levels (N1 - 75%
recommended dose of nutrients, N2 - 100% recommended dose of nutrients,
N3 - 125% recommended dose of nutrients, N4 -150% recommended dose of
nutrients and N5 - 175% recommended dose of nutrients). In the third season
(rabi), each of the kharif treatments were sub divided into three plots in the
same undisturbed layout to accommodate groundnut, maize and sunflower.
The graded nutrient levels to kharif rice were considered as main plot
treatments and rabi crops as sub - plot treatments. Recommended dose of
nutrients for the respective crops was applied during rabi.
The results indicated that graded nutrient levels noticeably altered the
growth parameters, yield attributes, yield, nutrient uptake and economic
returns of aerobic rice as well as the post harvest fertility status of soil, with
similar trend during both the years of study.
The growth attributes (plant height, total tillers m-2 and dry matter
production), yield attributes ( panicles m-2, number of grains panicle-1, filled
grains panicle-1 and 1000 gain weight), yield, nutrient uptake, economic
returns of rice and post harvest fertility status of soil were found to be the
highest with N5 (175% recommended dose of nutrients), which were
however, comparable with those under N4 (150% recommended dose of
nutrients) and all of them were at their lowest with N1 (75% recommended
dose of nutrients).
Graded nutrient levels to preceding aerobic rice exerted significant
influence on nutrient uptake, economic yield ( in terms of rice equivalent
yield) and economic returns of rabi crops as well as post harvest fertility
status of soil, with similar trend during both the years of study.
As regards the graded nutrient levels to preceding rice, N5 (175%
recommended dose of nutrients to kharif aerobic rice) has resulted in the
highest nutrient uptake, rice equivalent yield, economic returns of all the
three rabi crops and better post harvest fertility status of soil, which was
comparable with N4 (150% recommended dose of nutrients to kharif aerobic
rice), and all of them were at their lowest with N1 (75% recommended dose
of nutrients to kharif aerobic rice). Among all the rabi crops, groundnut crop
recorded the highest rice equivalent yield, economic returns and post harvest
soil available nitrogen, phosphorus and potassium. Nutrient uptake was
significantly higher with maize crop than the other two rabi crops, while all
of them at their lowest with sunflower.
Among all the cropping systems, sunhemp-rice-groundnut produced
the highest rice equivalent economic yield as well as the highest gross
returns, net returns and benefit cost ratio under the influence of N5 (175%
recommended dose of nutrients) applied to kharif rice. Post harvest soil
status of available nitrogen, phosphorus and potassium was also found to be
highest with the same nutrient level in the same cropping system, which
were comparable with N4 (150% recommended dose of nutrients to kharif
aerobic rice) in the above mentioned cropping system.
In conclusion, the investigation has revealed that sunhemp green
manuring-aerobic rice-groundnut cropping system with 150% recommended
dose of nutrients (120-60-60 N, P2O5 and K2O) to aerobic rice has resulted
in higher productivity and economic returns with improved soil fertility
status, thus satisfying all the criteria of sustainability.
Description
Keywords
STUDIES, NUTRIENT, MANAGEMENT IN AEROBIC, RICE-BASED, CROPPING, SYSTEMS