INTEGRATED MANAGEMENT OF NUTRIENT AND WEED IN YELLOW SARSON [Brassica rapa L. var. trilocularis (Roxb.) Kitam] UNDER RAINFED CONDITION
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Date
2018-07
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AAU, Jorhat
Abstract
An experiment entitled “Integrated management of nutrient and weed in yellow
sarson (Brassica rapa L. var. trilocularis (Roxb.) Kitam) under rainfed condition” was
conducted at Instructional-cum-Research Farm, Assam Agricultural University, Jorhat during
rabi seasons of 2016-17 and 2017-18 to find out the effect of integrated weed management
(IWM) on growth and yield of yellow sarson and a suitable integrated nutrient management
(INM) practice for yellow sarson. The experiment was laid out in factorial randomized block
design with three replications. The treatments consisted of five INM practices viz., control
(N0), RDF (60-30-30 kg/ha N, P2O5, K2O, N1), 25% RDF + 75% of N through vermicompost
(N2), 50% RDF + 50% of N through vermicompost (N3) and 75% RDF + 25% of N through
vermicompost (N4), and, three IWM practices viz., weedy check (W0), pendimethalin 0.75
kg/ha pre-em+MW 20DAS (W1) and pendimethalin 1.0 kg/ha pre-em+MW 20DAS (W2). The
soil of the experimental site was sandy loam in texture, acidic in reaction (pH: 5.6 and 5.5),
medium in organic carbon (0.58% and 0.54%), available N (259.86kg/ha and 255.75kg/ha)
and available K2O (160.82kg/ha and 156.49kg/ha) and low in available P2O5 (20.87kg/ha and
20.00kg/ha) in the years 2016-17 and 2017-18, respectively. The weed flora of the
experimental field were Paspalum conjugatum L., Axonopus compressus (Sw.)P. Beauv.,
Cynodon dactylon (L)Pers., Panicum repens L., and Eleusine indica (L) Gaertn., among the
grasses; Cyperus esculentus L. among the sedge; and Alternanthera philoxeroides Griseb.,
Soliva anthemifolia, Ageratum houstonianum Mill., Oxalis corniculata L., Melochia
corchorifolia L., Chenopodium album L., Commelina benghalensis L., Mimosa pudica L. and
Polygonum plebeium R.Br.
The data revealed that the density and dry weight of weeds during both the years were
found to be significantly lesser with N4 compared to rest of the treatments. As a result, the
content and uptake of N, P and K by weeds were found to be significantly lesser with N4.
Moreover, the growth parameters (barring N3 which was at par with N4) and yield attributing
characters were significantly improved due to N4. The highest seed yield (969.00 and
949.00kg/ha during 2016-17 and 2017-18, respectively) and stover yield (2921.11 and
2846.67kg/ha during 2016-17 and 2017-18, respectively) of yellow sarson were recorded with
N4. The oil content, oil yield, N, P and K content and uptake also increased with N4.
In respect of IWM, W2 i.e., pendimethalin 1.0 kg/ha pre-em + MW 20 DAS was
found to result in significantly lesser density and dry weight of weeds with lower NPK
content and uptake in weeds. The growth and yield attributing characters of yellow sarson
were improved with W2 which also recorded the highest seed yield (964.00 and 943.33 kg/ha
during 2016-17 and 2017-18, respectively) and stover yield (2900.67 and 2830.00 kg/ha
during 2016-17 and 2017-18, respectively). With regard to oil content, oil yield, N, P and K
content and uptake, the values were significantly higher with W2. The INM interacted
significantly with IWM in respect of seed and stover yields of yellow sarson. The
combination of N4W2 was found to be superior with 1210.00 and 1190.00 kg/ha seed yield
and 3673.33 and 3570.00 kg/ha stover yield during 2016-17 and 2017-18, respectively.
The comparative economics highlighted that N4W2 combination resulted in the
highest gross return (Rs. 62336.5/ha and Rs. 61285/ha during 2016-17 and 2017-18,
respectively), net return (Rs.39378.5/ha and Rs.38327/ha during 2016-17 and 2017-18,
respectively) and benefit:cost ratio (2.71 and 2.66 during 2016-17 and 2017-18, respectively).