EFFECT OF PRECEDING LEGUMES, NITROGEN LEVELS AND IRRIGATION SCHEDULES ON THE PERFORMANCE OF RABI SORGHUM
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Date
2015
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Acharya N.G. Ranga Agricultural University, Guntur
Abstract
A field experiment was conducted for two consecutive years during 2012 and 2013 at Indian Institute of Millets Research, Rajendranagar, Hyderabad to study the “Effect of preceding legumes, nitrogen levels and irrigation schedules on the performance of rabi sorghum” in strip – split plot design with three replications. Four strips of treatments including dhaincha, greengram and cowpea raised as preceding kharif legumes along with fallow are taken as main plot treatments. During rabi, sorghum was grown in split plot design taking strips of .kharif crops as main plots, four irrigation schedules (I1: Irrigation at panicle initiation, I2: Irrigation at panicle initiation and booting, I3: Irrigation at panicle initiation, booting and anthesis and I4: Irrigation at panicle initiation, booting, anthesis and milk stages) assigned to sub – plots and four nitrogen levels (0, 30, 60 and 90 kg ha-1) to sub – sub plots. Dhaincha was grown till the commencement of flowering and then incorporated in situ. The greengram pods were picked for seed and haulms were then turned down into the soil. The cowpea foliage was harvested for fodder and the stubbles were incorporated. The test variety of sorghum was Phule Suchitra (SPV-2048).
The results indicated that among the kharif legumes tested, greengram produced more economic yield in addition to the haulms for incorporation after harvest. Higher biomass was produced by dhaincha grown for green manure during both the years.
Author : RVT. BALAZZII NAAIIK
Title of the thesis : EFFECT OF PRECEDING LEGUMES, NITROGEN LEVELS AND IRRIGATION SCHEDULES ON THE PERFORMANCE OF RABI SORGHUM
Degree : DOCTOR OF PHILOSOPHY IN AGRICULTURE
Faculty : AGRICULTURE
Discipline : AGRONOMY
Chairperson : Dr. G. PRABHAKARA REDDY
University : ACHARYA N.G. RANGA AGRICULTURAL UNIVERSTY
Year of submission : 2015 ______________________________________________________________________
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Preceding kharif legumes, irrigation schedules and nitrogen levels noticeably altered the growth parameters, yield attributes, yield, nutrient uptake and economic returns of sorghum as well as the post harvest fertility status of soil, with similar trend during both the years of study. However, the interactions were not significant except on number of grains panicle-1 and earhead weight.
Significantly taller plants, larger LAI and higher dry matter production of rabi sorghum was with dhaincha - rabi sorghum followed by greengram – rabi sorghum. The least values for all the above parameters were obtained with fallow – rabi sorghum. Scheduling irrigation at four critical stages i.e. panicle initiation, booting, anthesis and milk stage recorded the higher values of above growth parameters which was significantly superior compared to the other irrigation schedules. Irrigation only at panicle initiation resulted in the lowest values. Application of 90 kg N ha-1 recorded significantly higher values of above growth parameters among the different levels of nitrogen tested.
Sorghum preceded by dhaincha recorded higher values of yield attributes, viz., length of the panicle, number of grains panicle-1, earhead weight and thousand grain weight which was, however, on par with the crop preceded by greengram. The least values of all the above parameters were obtained with fallow – rabi sorghum. Irrigating the crop at four critical stages recorded the higher values of above yield parameters which was significantly superior compared to the other irrigation schedules. Irrigation only at panicle initiation resulted in the lowest values. With regard to interaction, higher number of grains panicle-1 and earhead weight was with crop preceded by dhaincha along with four irrigations at critical stages. Application of 90 kg N ha-1 recorded significantly higher values of above yield attributes, which was, however, on par with 60 kg N ha-1. Lowest values were recorded with no nitrogen.
Significantly higher grain yield of sorghum was obtained by incorporation of dhaincha. Lowest grain yield was with sorghum when grown after kharif fallow. Grain yield of rabi sorghum was comparable to the crop grown after cowpea for fodder or greengram for seed. Irrigation to rabi sorghum at four critical stages recorded the significantly higher grain yield among the different irrigation schedules tested. Irrigating the crop at three critical stages was the next best treatment. The crop with only one irrigation at panicle initiation recorded the lowest grain yield. Application of 90 kg N ha-1 recorded higher grain yield, which was however on par with 60 kg N ha-1. Lowest grain yield of rabi sorghum was with no nitrogen.
The green manure of dhaincha enabled rabi sorghum to take up more nitrogen from 60 DAS till harvest during the both years. A significant increase in the uptake of nitrogen was recorded by the crop at 90 DAS and by both grain and stover at harvest due to the influence of the green manure
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of dhaincha. Irrigations at four critical stages viz., panicle initiation, boot leaf, anthesis and milk stage further enhanced the uptake of NPK during both the years. The uptake by grain and stover increased with increase in the number of irrigations from one to four. Higher uptake of nutrients was due to the application of 90 kg N ha-1at any stage of crop growth. Higher nitrogen use efficiency of 14.0 and 15.4 kg grain kg-1 N during 2012 and 2013 was due to the application of 30 kg N ha-1to sorghum preceded by dhaincha and irrigations at four critical stages viz., panicle initiation, boot leaf, anthesis and milk stage during 2012 and 2013. The nitrogen use efficiency reduced at higher levels of nitrogen application. Maximum profit was obtained from rabi sorghum preceded by greengram, fertilized with 60 kg N ha-1 and irrigated at all the 4 critical stages of moisture sensitivity despite more expenses on the cost of cultivation. The returns from the grain yield of greengram compensated the additional expenses on its cultivation over dhaincha. From the present investigation, it could be inferred that rabi sorghum preceded by dhaincha for green manure or greengram for seed with four irrigations at critical phases of panicle initiation, booting, anthesis and milk stage along with application of 60 kg N ha-1 has resulted in higher yield, more economic returns, post harvest nutrient status duly maintaining the soil health with higher microbial population in the soil.
Description
EFFECT OF PRECEDING LEGUMES, NITROGEN LEVELS AND IRRIGATION SCHEDULES ON THE PERFORMANCE OF RABI SORGHUM
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