EVALUATION OF WATER AND NITROGEN PRODUCTIVITY FOR MAIZE PRECEDED BY GREENGRAM UNDER DRIP IRRIGATION
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Date
2015
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Acharya N.G. Ranga Agricultural University, Guntur
Abstract
The present investigation entitled “Evaluation of water and nitrogen productivity for maize preceded by greengram under drip irrigation” was carried out during kharif and rabi seasons of 2013-14 and 2014-15 on sandy clay loam soils of S.V. Agricultural College Farm, Tirupati campus of Acharya N.G. Ranga Agricultural University of Andhra Pradesh.
During kharif, greengram was raised as bulk crop by following the recommended package of practices. After manual picking of greengram pods, the haulms were incorporated in to the soil. The rabi maize experiment was laid out in a split plot design with three replications. The treatments comprised of four main plots viz., M1 (drip irrigation at 0.7 IW/CPE ratio), M2 (drip irrigation at 0.8 IW/CPE ratio), M3 (drip irrigation at 0.9 IW/CPE ratio) and M4 (weekly check basin irrigation) and three sub plots viz., N1 (160 kg N ha-1), N2 (200 kg N ha-1) and N3 (240 kg N ha-1). Separately, unreplicated observational plot was also maintained with same treatments to maize but without preceding greengram for comparative study. To schedule the drip irrigation at prescribed IW/CPE ratios the treatments were maintained to field capacity in the top 0-45 cm depth i.e. only effective root zone depth, whereas for check basin irrigation the depth of water was 50 cm.
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Irrigation schedules and nitrogen levels significantly influenced the growth parameters, yield attributes, yield, quality, nutrient uptake, water use, economics and post harvest fertility status of the soil.
Weekly check basin irrigation resulted in the highest values of all the growth parameters (plant height, LAI, dry matter), yield attributes (cob length, cob girth, kernel weight cob-1, test weight), yield (kernel and stover yield), NPK uptake, nitrogen use efficiency and soil available NPK, which was at par with 0.9 IW/CPE ratio through drip irrigation and all of them were at their lowest with drip irrigation at 0.7 IW/CPE ratio.
Among the nitrogen levels, 240 kg N ha-1 resulted in the highest values of all the growth parameters (plant height, LAI, dry matter), yield attributes (cob length, cob girth, kernel weight cob-1, test weight) and yield (kernel and stover yield), NPK uptake and soil available NPK, which was superior over the remaining doses. However, Nitrogen use efficiency was found to be highest with 200 kg N ha-1. While, the lowest of all the above said parameters were recorded with 160 kg N ha-1, except nitrogen use efficiency, which was found to be lowest with 240 kg N ha-1.
With regard to interaction effect, weekly irrigation along with 240 kg N ha-1 resulted in superior values of growth parameters, yield attributes and yield, N uptake and soil available NPK which was on par with the combination of drip irrigation at 0.9 IW/CPE ratio with 240 kg N ha-1. Drip irrigation at 0.7 IW/CPE ratio with 160 kg N ha-1 recorded the lowest values of growth parameters, yield attributes and yield, N uptake and soil available NPK.
Protein content in maize kernel was highest with drip irrigation scheduled at 0.9 IW/CPE ratio, which was at par with weekly check basin irrigation. Starch content was found to be highest with weekly irrigation schedule. Among the nitrogen levels, 240 kg N ha-1 resulted in highest protein content whereas, starch content was not significantly influenced by the nitrogen levels. The lowest protein and starch content were resulted with drip irrigation at 0.7 IW/CPE ratio. Application of nitrogen at 160 kg ha-1 resulted in the lowest protein content.
Crop evapotranspiration and moisture extraction pattern were observed to be highest with check basin irrigation scheduled at weekly intervals. Among the nitrogen levels, 240 kg N ha-1 recorded the highest levels of above parameters. Water use efficiency and water productivity found to be highest with drip irrigation scheduled at 0.9 IW/CPE ratio which was at par with 0.8 IW/CPE ratio, in main plots and in 240 kg N ha-1 in sub plots. Pertaining to interaction effect, weekly check basin irrigation coupled with 240 kg N ha-1 resulted in the highest ETc while, the highest water use efficiency and water productivity was noticed with the combination of drip
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irrigation scheduled at 0.9 IW/CPE ratio and 240 kg N ha-1. The lower values of ETc, moisture extraction pattern and water use efficiency were registered with drip irrigation at 0.7 IW/CPE ratio in main plots and with 160 kg N ha-1 in sub plot treatments. While, the lowest water productivity was obtained with weekly check basin irrigation and with 160 kg N ha-1 among nitrogen levels.
The higher gross returns were realized with weekly check basin irrigation schedule, whereas, the net returns and returns per rupee invested was higher with drip irrigation scheduled at 0.9 IW/CPE ratio. Among the nitrogen levels, 240 kg N ha-1 resulted in higher gross returns, net returns and returns per rupee invested. Weekly check basin irrigation along with 240 kg N ha-1 registered higher gross returns, while the net returns and returns per rupee invested were higher when irrigation was scheduled at 0.9 IW/CPE ratio through drip along with 240 kg N ha-1. The lowest monetary returns were realized with irrigation schedule of 0.7 IW/CPE ratio and with nitrogen level of 160 kg N ha-1.
All the above said parameters (growth parameters, yield attributes, yield, quality parameters, ETc, water use efficiency, water productivity, NPK uptake, nitrogen use efficiency, soil available NPK and economic returns) were at their lowest with no residue incorporation as against maize grown with greengram crop residue incorporation.
Based on the outcome of the investigation, it could be inferred that for maximum yield, monetary returns and water productivity under limited water conditions, drip irrigation scheduled at 0.9 IW/CPE ratio coupled with 240 kg N ha-1 is the better combination. Growing greengram, as a preceding crop and using it for residue incorporation after realizing the economic produce will be a promising option for maintaining soil fertility status along with more returns per rupee invested.
Description
EVALUATION OF WATER AND NITROGEN PRODUCTIVITY FOR MAIZE PRECEDED BY GREENGRAM UNDER DRIP IRRIGATION
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