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Birsa Agricultural University, Ranchi

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Subject: Agricultural Physics and Meteorology × Author: Kujur, Abha Nutan × End date: 2019 × Start date: 2013 × Type: Thesis ×
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    ThesisItemOpen Access
    IMPACT OF MICROCLIMATIC VARIATION ON HYBRID RICE (Oryza sativa L.) UNDER AEROBIC CONDITION
    (Birsa Agricultural University, Kanke, Ranchi, Jharkhand, 2015) Kujur, Abha Nutan; Wadood, A.
    In view of the anticipated adverse impact of microclimatic conditions on hybrid rice under aerobic conditions in Jharkhand, a field experiment was conducted at Birsa Agricultural University farm (Lat:23⁰17’N, Long:83⁰19’E, Alt:625 m above MSL) in Kharif 2013 with 4 cultivars viz, DRRH-3, PAC-837, ARIZE TEJ and DRRH-2 having 3 sowing dates on 21st June, 1st July and 11th July to assess and quantify the impact of microclimatic conditions in aerobic rice cultivars. The outcomes of the study have been found of utmost importance which would help in proper management of rice cultivation in Jharkhand so as to minimize the adverse impact of microclimatic variation on rice yield. Soil moisture conditions in the aerobic rice field remained optimum (well above PWP) under all sowing dates under the weather and monsoon pattern prevailed during the Kharif season 2013.Variation of soil moisture between upper and lower soil layer was more pronounced in case of last sowing (11th July) than preceding sowings (21st June and 1st July).On an average the highest GDD of 1851 was required by the DRRH-3 to attain physiological maturity stages followed DRRH-2 (1820) followed by PAC-837 (1776) and ARIZE TEJ (1737). The average GDD requirement of varieties was highest under 1st July (1821) followed by 21st June (1815) and 11th July (1752). Among the varieties variation in GDD requirement was minimal at early stage (PI & booting) than latter stages while the variation in GDD among the dates of sowing was negligible at all the stages . Rice varieties sown on 21st June matured in 120 days while subsequently delayed sown crop (1st July and 11th July) matured in more number of days (124 and 125 days). Among the varieties, the highest grain yield of 64.6 q/ha was obtained in PAC-837 under 21st June sowing. Among the dates of sowing the variety DRRH-3 performed best under 1st July sowing (57.6 q/ha). In case of the rest three varieties the best performance recorded under 21st June sowing and every delay in sowing reduced the grain yield. The gap between leaf temperature and air temperature remained narrower till 90 DAS in 21st June, 80 DAS in 1st July and 70 DAS in 11st July where after the gap widened under all the sowings suggesting that maintenance of optimum soil moisture after 70-90 DAS would be essential. On an average, crops under all the sowings faced heat stress during 100-110 DAS which may be taken as crucial stage for combating the stress by maintaining soil moisture around the field capacity, may be by irrigating the crop. Maximum solar radiation interception was observed to be after 80 DAS under all sowing dates. Relative humidity within crop canopy was found to remain around 65% with least variation at 80 DAS onwards. The variety PAC-837 producing highest yield of 64.6q/ha under 21st June sowing also exhibited the highest water productivity of 11.78 kg/mm/ha. CONCLUSIONS 1. Phenology and microclimatic conditions of four aerobic rice varieties have been recorded and well understood which may be utilized in further research and for rendering appropriate advisories under the prevailing weather conditions. 2. Timely sowing of aerobic rice varieties on and around 21st June could harness maximum benefits of the prevailing microclimatic conditions by performing better (all four varieties) than subsequently delayed sowings. 3. The variety PAC-837 is found the best with respect to economical yield, water use efficiency and heat tolerance.