Weed management and water productivity of Napier Bajra hybrid (Pennisetum purpureum × Pennisetum glaucum) in relation to mulch and irrigation regimes
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Date
2016
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Punjab Agricultural University, Ludhiana
Abstract
The present study “Weed management and water productivity of Napier Bajra hybrid (Pennisetum
purpureum × Pennisetum glaucum) in relation to mulch and irrigation regimes” was carried out at Students’
Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana, in kharif 2014 and
2015. Experiment (Expt.) I investigated critical period of crop-weed competition in Napier Bajra hybrid in
split plot design with three replications; two planting materials (root slips and stem cuttings) in main plot and
ten weed infestation durations [weed infested till initial 10, 20, 30, 40 and 60 days after planting (DAP) and
weed free for initial 10, 20, 30, 40 and 60 DAP] in sub plot. In Expt. II, weed intensity and performance of
Napier Bajra hybrid keeping four levels of paddy straw mulch (no mulch, mulch @ 5 t ha-1, 7.5 t ha-1 and 10
t ha-1) in main plot and three irrigation schedules (IW/CPE ratio of 0.8, 1.0 and 1.2) in sub plot was
evaluated in split plot design with three replications. In Expt. I, planting materials and weed infestation
durations significantly influenced the growth and yield of Napier Bajra hybrid. Root slips recorded
significantly higher green (417.7 and 433.5 q ha-1) and dry (78.7 and 82.6 q ha-1) fodder yield over stem
cutting in 2014 and 2015, respectively. The green and dry fodder yield were significantly higher in treatment
kept weed free throughout the season that was at par with treatment kept weed free up to 40 days, 30 days
and kept weedy up to 10 DAP. The reduction in green fodder yield in control (weedy check) was observed
by 44.6 and 41.7 % than weed free conditions during 2014 and 2015, respectively among different weed
infestation durations. The critical period of crop-weed competition was found to be 10-30 DAP on the basis
of different weed infestation durations. Gompertz and logistic equations fitted to yield data in response to
increasing period of weed control and weed interference that showed root slips (4-32 days) had longer
critical period of 6 days that stem cutting (5-27 days). However, Napier Bajra hybrid planted with root slips
significantly overcome the weed pressure than stem cutting. The nutrient uptake of Napier Bajra hybrid was
improved in crop planted with root slips and significantly increased in treatments kept weed free throughout
the season that was at par with crop kept weed free for 40 days, for 30 days and kept weedy for 10 days
during both years. In Expt. II, the results revealed that significantly higher green, dry fodder yield, water use
efficiency (WUE) and lowest weed intensity were recorded under mulch level of 10 t ha-1 and it was being at par
with 7.5 t ha-1 mulch application. Irrigation schedule of 1.2 IW/CPE ratio produced maximum green and dry fodder
yield that was at par with IW/CPE ratio of 1.0. The WUE was significantly higher under irrigation schedule at
IW/CPE ratio of 0.8 followed by IW/CPE ratio of 1.0. Irrigation applied at IW/CPE ratio of 1.0 saved 7.5 cm
irrigation water over IW/CPE ratio of 1.2 during hot summer months of April-June. Whereas, during the entire
season (April-November), irrigation scheduled at IW/CPE ratio of 1.0 saved 22.5 cm irrigation water over
IW/CPE ratio of 1.2 during 2014 and 2015 without significant reduction in fodder yield of Napier Bajra hybrid.
The nutrient uptake and quality parameters of Napier Bajra hybrid improved significantly with mulch level of 10 t
ha-1 that was at par with 7.5 t ha-1. Whereas, among the irrigation schedules, IW/CPE ratio of 1.2 was at par with
IW/CPE ratio of 1.0 but was significantly higher than IW/CPE ratio of 0.8. Thus, it can be concluded that mulch
level of 7.5 t ha-1 and irrigation schedule at IW/CPE ratio of 1.0 significantly improved the fodder yield, WUE,
nutrient uptake and quality of Napier Bajra hybrid. The crop should be kept weed free from 10 to 30 DAP to
prevent the significant reduction in fodder yield.
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Keywords
Napier Bajra hybrid, planting material, crop-weed competition, water use efficiency, mulch levels, irrigation schedules, fodder yield.