INTEGRATED NUTRIENT MANAGEMENT IN RICE–BUCKWHEAT CROPPING SEQUENCE
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Date
2020-06
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Publisher
AAU, Jorhat
Abstract
A field experiment entitled “Integrated Nutrient Management in Rice -
buckwheat cropping sequence” was conducted during kharif of 2016 and 2017 and rabi
of 2016-17 and 2017-18 at Krishi Vigyan Kendra (KVK) farm of Kokrajhar district
under Lower Brahmaputtra Valley Zone (LBVZ) of Assam. The treatment consisted of
Integrated Nutrient Management (INM) viz., T1 (control), T2 (100% RDF), T3 (100%
RDF + FYM @ 10 t ha-1), T4 (75% RDF + 25% N through FYM), T5 (75% RDF +
25% N through vermicompost), T6 (50% RDF + 50% N through FYM), T7 (50% RDF +
50% N through vermicompost) and T8 (FYM @ 1 t ha-1 + mixture of Azospirillium
amazonens A-10 and Bacilllus megaterium P-5 @ 4 kg ha-1, + Rock phosphate@ 10 kg,
MOP @ 40 kg ha-1) applied to kharif rice (as main-plot treatment in rabi season) in
randomised block design and replicated three times. In succeeding rabi season, each
main- plot treatment was splitted into three sub plot treatments with three levels of
recommended dose of fertilizers viz., B1 (0% RDF i.e. control), B2 (50 % RDF) and B3
(100% RDF) to buckwheat resulting into twenty four treatment combinations and
replicated three times in split plot design.
The result revealed that the highest grain yield (54.13 and 52.71 q ha-1)
and straw yield (64.23 and 64.18 q ha-1) of rice were recorded with the application of
treatment T3 (100% RDF + FYM @10t ha-1) during kharif, 2016 and 2017, respectively.
Most of the growth and yield attributes, nutrient content and their uptake by the
crop, organic carbon and available NPK status of soil after harvest of the kharif rice
were maximum under application of T3 (100% RDF + FYM @ 10 t ha-1) followed by
treatment T5 (75% RDF + 25% N through vermicompost) during both the years of
experimentation.
The highest net return (Rs.36417 ha-1) and B: C ratio (1.99) were
obtained with the treatment T3 (100% RDF + 10 t FYM ha-1) followed by T5 (75% RDF
+ 25% N through vermicompost) having net return of Rs.32534 ha-1 and B:C ratio of
1.92 to kharif rice.
During rabi season, the residual effect of treatment T3 (100% RDF +
FYM @10 t FYM ha-1) showed higher growth, yield attributes, seed and stover yields of
buckwheat as well as nutrient content and their uptake by the crop during both the years
of experimentation. The highest seed yield (12.76 and 13.65 q ha-1) and stover yield
(23.52 and 25.47 q ha-1) were recorded with the residual effect of the treatment T3
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(100% RDF + FYM @10 t FYM ha-1) in rabi 2016-17 and 2017-18, respectively.
Lower bulk density and higher organic carbon value and improvement in status of
available NPK in soil after harvest of buckwheat (end of the rice – buckwheat sequence)
were also recorded with the residual effect of T3 (100% RDF + FYM @ 10 t ha-1)
applied to the preceding kharif rice. In terms of monetary return, the highest net return
(Rs. 19070 ha-1) and B: C ratio (2.26) were recorded with the residual effect of T3
(100% RDF + FYM @ 10 t ha-1) followed by T5 (75% RDF + 25% N through
vermicompost) with net return (Rs. 15630 ha-1) with B: C ratio (2.03) to buckwheat on
the basis of average of two year (2016-17 and 2017-18) data.
The result further revealed that the treatment B3 (100% RDF) resulted in
higher values of growth, yield attributes, seed and stover yields, harvest index of rabi
buckwheat as well as nutrient content and its uptake by crop, organic carbon and
available NPK status with lower bulk density of soil after harvest of crop among the
different levels of RDF (NPK) directly applied to buckwheat crop during both the
years of investigation. Among RDF levels to buckwheat, maximum net return
(Rs.14894 ha-1) with B: C ratio (1.89) was obtained with B3 (100% RDF). The treatment
combination of T3B3 i.e. 100% RDF + FYM @10 t ha-1 with 100% RDF calculated
highest net return (Rs.26674 ha-1) and B:C ratio (2.60) followed by treatment
combination of T5B3 (75% RDF + 25% N through vermicompost with 100% RDF) with
net returns of Rs. 19758 per hectare with B:C ratio of 2.18.
The performance of rice-buckwheat cropping sequence was assessed on
the basis of rice equivalent yield, net monetary returns and B:C ratio. In respect of all
the above assessment, the application of 100% RDF + FYM @ 10 t ha-1 to kharif
rice and 100% RDF to buckwheat was the most beneficial combination compared to
rest of the treatments. However, the interaction differences were not up to the
significant extent.