INFLUENCE OF NUTRIENT MANAGEMENT PRACTICES AND MICROBIAL INOCULANTS ON PRODUCTIVITY AND SOIL QUALITY OF LOWLAND RICE IN EASTERN HIMALAYAS
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Date
2017
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DIVISION OF AGRONOMY ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
A field study entitled “Influence of nutrient management practices and
microbial inoculants on productivity and soil quality of lowland rice in eastern
Himalayas’’ was conducted during Kharif 2016 at the research farm of ICAR
Complex for NEH Region (Umiam) Barapani, Meghalaya. The soil of the
experiment site was sandy clay loam in texture, acidic (5.0) in nature and having low
available N (252.98 kg/ha) and P (8.19 kg/ha), but high available K content and soil
organic carbon (2.51%) content. The experiment was laid out in a split plot design
with three main plots and four sub-plot treatments with three replications. The
popular rice variety ‘Shahsarang 1’ was taken. Main plot treatments included 3
nutrient management practices viz., organic, inorganic (mineral fertilizer at RDF of
N80P40K40) and integrated nutrient management (INM) having 75% mineral + 25%
organic. In sub plot 4 microbial inoculants viz., control, Azospirillum, Azospirillum+
Phosphate Solubilizing Bacteria (PSB) and Azospirillum+ PSB + Zinc Solubilizing
Bacteria (ZnSB) were taken. Results showed that among the nutrient management
practices, highest plant height, leaf area index and dry matter accumulation were
observed in INM practice followed by inorganic and organic nutrient management.
The similar trend was also observed in case of yield attributing characters viz.,
tillers/m2
, grains/panicle, panicle length and fertile grains/panicle. The highest grain
yield (4.27 t/ha) was recorded in INM followed by inorganic (4.08 t/ha) and organic
(3.65 t/ha) nutrient management and the difference between both INM and inorganic
was statistically at par. This was the first year of organic farming in that field and
there was a yield advantage of 12% and 17% in inorganic and INM over organic
management, respectively. Among the three nutrient management practices, the
highest cost of cultivation (₹ 28854/ha) was recorded under organic nutrient
management followed by INM and inorganic treatment in reducing order. However,
the highest gross return (₹ 74399/ ha) and net return (₹ 52508/ ha) were observed in
INM practice with combined inoculation of Azospirillum+ PSB+ ZnSB. Benefit: cost
(B: C) ratio also showed the same trend like gross and net return and it was ranging
between 1.03 (organic- control) to 2.41 (INM with Azospirillum+ PSB + ZnSB).
Higher enzymatic activity, root growth parameters and better grain quality of grains
were observed in organic nutrient management practice followed by INM and
inorganic nutrient management. Microbial inoculants significantly influenced the
plant growth, yield attributes, yields and nutrient uptake of rice over the control
treatment. The highest (4.25 t/ha) and lowest (3.72 t/ha) grain yields were obtained in
Azospirillum+ PSB+ ZnSB and control treatments, respectively. There was a yield
advantage of 5.9%, Whereas 10.2% and 14.2% due to the inoculation with
Azospirillum alone, Azospirillum+ PSB and Azospirillum+ PSB+ ZnSB as compared
to control treatment. Among the soil microbiological parameters, the highest value of
soil FDA (11.80 µg fluorescein/g soil/hr), alkaline phosphatase activity (162.58 µg
p-NP/g soil/ hr), soil microbial biomass carbon (MBC) (174.49 g/g dry soil) were
higher in organic treatment compared to inorganic and INM. All the microbial
activities were higher at 60 DAT as compared to crop harvest stage. The availability
status of the N, P, K and Zn in soil at crop harvest was highest in INM practice
followed by inorganic and organic management, the highest soil organic carbon
(2.62%) was recorded in organic nutrient management followed by INM (2.55%) and
inorganic (2.52%) treatment. Among microbial inoculation treatments, all the three
inoculation treatments recorded significantly higher available N and P over the
control. It was concluded that farmers may adopt INM including 75% mineral
fertilizer with 25% organic input for higher crop productivity, profitability and grain
quality of low land rice under eastern Himalayas.
Description
t 9637
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