Fortnight Of June Research Articles

Influence of Major Abiotic Factors on the Population Trend of Tetranychusurticae Koch on Okra at Samastipur, Bihar, India

Field experiments were conducted to study the population fluctuation of the phytophagous mite (Tetranychus urticae Koch) in okra and its relation with different abiotic factors under field conditions during summer 2023 at Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar. The population of T. urticae in okra commenced from the first fortnight of March and reached its peak of 34.60 mites/ 2.5cm2 leaf areas on the first fortnight of June. There was a positive and significant correlation of the population of T. urticae with maximum temperature (r = 0.779**) and minimum temperature (r = 0.699*).

Effect of Time of Transplanting and Spacing on Tulsi (Ocimum sanctum)

An experiment investigating the impact of transplanting time and spacing on Tulsi (Ocimum sanctum) was conducted over three Kharif seasons from 2018-19 to 2020-21 at AICRP on Medicinal, Aromatic Plants and Betelvine. Twenty treatment combinations were arranged in a FRBD design. Transplanting times varied from June to August, with spacing options ranging from 60x45 cm to 75 x 60 cm. Recorded observations included plant height, primary branches per plant, fresh herbage yield, and dry herbage yield. Results indicated significant differences across all parameters based on transplanting time and spacing. Transplanting during the first fortnight of July (D3) resulted in the highest values for plant height (98.20 cm), branches per plant (16.63), fresh herbage yield (99.98 q/ha), and dry herbage yield (18.91 q/ha). The treatment of transplanting during the second fortnight of June (D2) showed comparable results. Among spacing options, 60 x 45 cm (S1) demonstrated the most favorable outcomes. Notably, the combined treatment of transplanting during the first fortnight of July with 60 x 45 cm spacing (D3S1) yielded the highest plant height (99.21 cm), fresh herbage yield (122.54 q/ha), and dry herbage yield (23.02 q/ha). Economically, this treatment also proved superior, with a net monetary return of ₹91453/- and a B:C ratio of 1.99. Overall, findings suggest that transplanting Tulsi seedlings between the second fortnight of June and the first fortnight of July, coupled with 60 x 45 cm spacing, maximizes productivity and economic returns.

Effect of Different Growing Environments of Pigeonpea Cultivars on Population Dynamics of Clavigralla gibbosa and its Relationship with Microclimate

The field experiment was carried out at research farm of Department of Agricultural Meteorology, Chaudhary Charan Singh Haryana Agricultural University, Hisar, during Kharif season 2017-18 to study the influence of different growing environments on Clavigralla gibbosa population dynamics and its relationship with microclimate of pigeonpea cultivars. The results revealed that the egg masses and adult population of C. gibbosa were first recorded during the 38th SMW and continued until crop harvesting in all cultivars and D1 (First fortnight of May), and D2 (First fortnight of June) sown crops, whereas it was observed during the 40th SMW and 39th SMW in the D3 (Second fortnight of June) sown crop, respectively. Mean number of egg masses of C. gibbosa (0.15 egg masses/plant) and population of adults (1.24 adults/plant) recorded highest under D1 sown crop, whereas, among cultivars, it was found higher (0.15 egg masses/plant) and (1.18 adults/plant) under cultivar Paras. The nymphal population of C. gibbosa initially noticed during 38th SMW in Manak cultivar sown on D1 and D2, while, in cultivars Paras and UPAS-120, it was noticed during 39th SMW and in D3 sown crop on 40th SMW. Among different date of sowings, higher nymphal population (0.22 nymphs/plant) was found in D1 sown crop while among different cultivars, it was highest (0.21 nymphs/plant) on cultivar Manak. Non-significant negative correlation was obtained between egg masses laid by C. gibbosa and temperature while non-significant positive correlation was obtained with relative humidity in cultivar Manak. In cultivar Paras, non-significant positive correlation with temperature while non-significant negative correlation with relative humidity. In cultivar UPAS-120, non-significant positive correlation was found with both temperature and relative humidity. Significant negative correlation was obtained between nymphal population of C. gibbosa and temperature while relative humidity showed significant positive correlation with tur pod bug nymphal population in all three cultivars. Adult population of C. gibbosa showed significant positive correlation with temperature while non-significant negative correlation with relative humidity in all cultivars. A negative linear relationship was found between temperature and nymphal population of C. gibbosa while relative humidity showed positive linear relationship on all the three varities i.e., Manak, Paras and UPAS-120 explaining the variability up to 65 and 49 per cent, 58 and 59 per cent and 53 and 55 per cent, respectively.

Impact of climatic factors and vector population on incidence of Phyllody in Sesame under rainfed cultivation

Phyllody is a severe disease caused by a phytoplasma and transmitted by leaf hopper, Orosius albicinctus Distant is a major controlling factor in accomplishing full yield potential of the sesame crop. Sesame crop was grown during kharif season of the year 2018 and 2019 with three sowing dates to investigate the influence of vector population and climate variability on occurrence of phyllody and the pooled data was analyzed. Studies on correlation of leaf hopper population and climatic factors indicated that, the leaf hopper population evinced significant positive correlation with maximum temperature (r=0.775), minimum temperature (r=0.525) and mean temperature (r=0.7), while, non-significant negative correlation with minimum relative humidity (r=-0.3), mean relative humidity(r =-0.41) and significant negative correlation with maximum relative humidity (r=-0.524) and rainfall (r =-0.55). Among the three sowing dates, the highest population was observed in the crop sown during first fortnight of June followed by crop sown during the second fortnight of June and first fortnight of May. Correlation between the climatic factors and phyllody incidence has indicated that the phyllody exhibited significant positive correlation with maximum temperature (r=0.709), minimum temperature (r=0.535) and mean temperature (r=0.705) while, non-significant negative correlation with maximum relative humidity (r=-0.445), minimum relative humidity (r=-0.242), mean relative humidity(r=-0.338) and significant negative correlation with rainfall (r=-0.565). Phyllody incidence was highest in the crop sown in the second fortnight of May, incidence was significantly decreased with delayed sowing in both the years. It was also revealed that the vector population had significant positive correlation with the phyllody incidence (r=0.979). Variation in yield realization was also observed owing to dates of sowing. Higher yields were recorded in the crop sown during first fortnight of June (372.2 kg/ha) and second fortnight of May (365.5 kg/ha) compared the to crop sown during second fortnight of June (298.6 kg/ha).

Population Dynamics of Mango Fruit Flies Bactrocera spp.

Population dynamics of fruit flies Bactrocera dorsalis Hendel and B. correcta Bezzi were studied in mango ecosystem at Veppalampatti location in Krishnagiri district of Tamil Nadu from October 2017 to September 2018. The fluctuations in the occurrence of adult fruit flies were assessed by methyl eugenol trap catches at fortnight intervals in fixed locations. The results revealed that B. dorsalis reached the first peak (116.00 flies/trap) in first fortnight of June, 2018. Relatively, the initial counts of B. correcta was maximum and the first peak (195.00 flies/trap) was observed during first fortnight of October, 2017. Correlation of trap catches with weather parameters revealed that B. dorsalis trap catches were influenced to an extent of 63%, whereas B. correcta occurrence was correlated with rainfall only.

Simulation and analysis of maize (Zea mays L.) yield trend under different emission scenarios in Ludhiana district of Punjab

The study helps us to understand the future scenario of maize yield under current farming practices. The maximum, minimum temperature and rainfall as projected by the four selected global circulation models (GCMs) (CSIRO-Mk3.6.0, FIO-ESM, IPSL-CM5A-MR and Ensemble of seventeen GCMs) were used for yield simulation of maize cultivars (PMH1 and PMH2) in Ludhiana region of Punjab using CERES-Maize. Yield decline was observed under experimental dates of sowing (28th May, 6th June, 15th June and 24th June) for all the GCMs except FIO-ESM which predicted increase in yield for both the cultivars PMH1 (+22.13)) and PMH2 (+14.28) on 24th June. The projections revealed that the region can experience large decrement in maize yield under RCP 8.5 (high emission scenario) and small under RCP 2.6 (low emission scenario). Though the second fortnight of June could be considered as a better sowing date but a single model prediction is not reliable. Thus, further analysis of sowing window is required.

Microclimate Modification through Groundnut-Pigeon Pea Intercropping System and its Effect on Physiological Responses, Disease Incidence and Productivity

Background: Groundnut (Arachis hypogaea) is the predominant leguminous oilseed crop of India which has turned out to be a sensitive victim to climate change episodes like rising CO2 levels, erratic rainfall pattern, high temperature and moisture stress leaving deleterious imprints in physiology, disease resistance, fertility and productivity. Globally climate change is anticipated to pull down groundnut productivity by 11-25%. Agronomic manipulations like altered time of sowing, intercropping and irrigation management helps in microclimate modification towards reaping higher productivity and economic returns in groundnut. Methods: Field experiments were conducted during 2019-2021 on sandy clay loam soil (Fluventic Ustropept) in a Randomized Block Design with three factors viz., differential cropping systems (sole groundnut, groundnut + red gram intercropping), rainfed and irrigation systems and differential sowing windows (Second fortnight of June, first and second fortnights of July). Growth parameters, physiological traits viz., photosynthetic rate, transpiration rate, stomatal conductance, canopy temperature and light interception, incidence of foliar diseases viz., leaf spot and rust; soil borne disease viz., stem rot, root rot and productivity of groundnut were recorded at critical crop growth stages. Result: Canopy temperature was higher in sole groundnut system while light interception was higher in groundnut - redgram intercropping system, however system productivity did not register statistical superiority between the cropping systems. Irrigated system exerted its influence over rainfed system in terms of pod and kernel yield of groundnut. Sowing of groundnut during second fortnight of June was beneficial than July sowing in pod and kernel yield of groundnut due to uniform distribution of rainfall during the growth and reproductive phases of crop. Although differential cropping systems did not register their impact on disease incidence of groundnut, irrigated system and first sowing windows recorded minimum incidence of root rot, stem rot, early leaf spot, late leaf spot and rust diseases compared to rainfed system and July sowing.

Effect of date of sowing and rainfall on sustainability of yield and rainwater use efficiency in cereal crops under arid alfisols

An assessment of the effects of date of sowing and crop seasonal rainfall on the sustainability of yield and rainwater use efficiency (RWUE) of sorghum, pearl millet and foxtail millet sown on five dates at 15 days interval from first fortnight of June to first fortnight of August during 2009 to 2014 under arid Alfisols at Anantapur has been made in this paper. A suitable date of sowing has been identified for each crop based on the relationships sorghum equivalent yield with crop seasonal rainfall and crop growing period observed in the 6-year study. The yield was significantly influenced by the variation in the crop seasonal rainfall and crop growing period when sown on different dates of sowing. It was significantly higher when crops were sown with the onset of monsoon in the first fortnight of June, and decreased with the subsequent sowings. Among crops, sorghum attained maximum mean yield of 923 kg ha-1 with RWUE of 2.73 kg ha-1 mm-1; while pearl millet attained mean yield of 873 kg ha-1 with RWUE of 2.95 kg ha-1 mm-1 and foxtail millet attained mean yield of 646 kg ha-1 with RWUE of 1.64 kg ha-1 mm-1 when sown during first fortnight of June. Based on the ranks assigned to the yield attained on different dates of sowing in different years, pearl millet was superior for sustaining maximum yield and RWUE comparedto sorghum and foxtail millet under arid Alfisols at Anantapur.

Yield Improvement and Nutrient Uptake of Little Millet (Panicum sumatrense) for Agronomic Interventions

Field experiments were conducted during kharif, 2019 and kharif 2020 at S.V. Agricultural College Farm, Tirupati with three different times of sowing of little millet (second fortnight of June, first fortnight of July and second fortnight of July) in combination with three methods of establishment (Broadcasting, Sowing at 30 cm × 10 cm and transplanting 20 days old seedlings) and three nitrogen levels (20 kg N ha-1, 30 kg N ha-1 and 40 kg N ha-1). The results of the experiment revealed that among the three times of sowing, second fortnight of June sowings recorded higher grain yield, straw yield and nutrient uptake of little millet while lower values of these were obtained with July second fortnight sown crop during both the years of study. Transplanted little millet resulted in superior grain yield, straw yield and nutrient uptake compared to broadcasting and sowing at 30 cm × 10 cm. Maximum values of grain yield, straw yield and nutrient uptake were observed with application of 40 kg N ha-1 while minimum values of these parameters were obtained with application of 20 kg N ha-1. Transplanting little millet during second fortnight of June along with the application of 40 kg N ha-1 achieved higher grain and straw yield besides nutrient uptake by grain.

Relationship Between Stink Bug Populations in Winter Shelters and Atmospheric Variables in Soybean Growing Areas in Southern Brazil.

Stink bugs (Pentatomidae) are among the main entomological problems in the international farming. Their ability in using alternative plants (refuges) during the off-season is one of the reasons that led them to the status of key pests in several crops. Like other insect species, stink bugs are subject to atmospheric variations. Therefore, the objective of this experiment was to evaluate the abundance, the co-occurrence, and its variations according to the weather in the off-season. The work was conducted between 2014 and 2018, in the municipality of Cruz Alta, state of Rio Grande do Sul (RS), Brazil. Every year, refuges formed by Poaceae and located around the cropped area were evaluated in the second fortnight of June, corresponding to the beginning of the winter solstice. Atmospheric variables corresponding to the evaluation period were used to explain the variation in the populations. In short, our results demonstrated interannual variations in the population abundance of stink bugs in the evaluated refuges. We also found variations in the co-occurrence between species. Finally, we demonstrate the trend in the increase in these refuges in years with cold and dry off-seasons.

Thermal energy utilization in mungbean (Vigna radiata L.) as influenced by sowing times and genotypes

Field experiment was conducted to study the thermal energy utilization in mungbean as influenced by sowing times and genotypes during Kharif season of 2014 and 2016 at Research farm of CCS Haryana Agricultural University, Hisar, India. Experiment was laid out in split plot design with four main-plot treatments of sowing times (2nd fortnight of June, 1st fortnight of July, 2nd fortnight of July and 1st fortnight of August) and four sub-plot treatments comprised of genotypes (MH 421, Basanti, Sattya and MH 318). The results indicated that yield and yield attributes, phenology, agro-meteorological indices (GDD, HTV, HYTV, PTU and PAR) and yield based thermal energy use efficiencies (HUE, HTUE, HYTUE, PTUE and RUE) were significantly influenced by sowing times and genotypes. Early sowing (2nd fortnight of June) of mungbean was found more suitable and recorded significantly higher yield and thermal energy use efficiencies. Among the genotypes MH 318 was recorded with maximum thermal use efficiencies followed by MH 421.

Population dynamics of green apple aphid Aphis Pomi De Geer (Homoptera: aphididae) and Its Natural enemies in apple orchard of Kashmir

Population dynamics of green apple aphid (Aphis pomi) in relation to the natural enemies and weather parameters was studied in three districts viz., Srinagar, Budgam, and Ganderbal of Kashmir during 2012–13 and 2013–14. The peak population of A. pomi was recorded as 39.5 and 37.0 aphids/shoot in Srinagar; 42.6 and 47.0 aphids/shoot in Budgam and 41.3 and 54.8 aphids/shoot in Ganderbal at 2nd fortnight of June during 2012–13 and 2013–14, respectively with exception during 2013–14 in Ganderbal the peak was attained at 1st fortnight of July. The natural enemies include coccinellids, syrphid fly and Chrysoperla and were recorded highest in 1st fortnight of July except Srinagar was on16th June during both years. Highest % of parasitization was found on 2nd fortnight of July and ranged 14.2 to 15.2% and 13.4–15.6% during 2012–13 and 2013–14, respectively. The A. pomi overwintering nymphs was 0.3 and 0.5/10 buds and their mean maximum population was 0.66 and 1.0/10 buds on 2nd fortnight of December during 2012–13 and 2013–14, respectively in Srinagar and trend was also similar in other locations of Kashmir. The temperature played major role to buildup the population of aphid, its predators and parasitoids and after attaining peak population of natural enemies, the aphid population tends to decrease. Relative humidity had a positive influence along with temperature on aphid population and rainfall had negative influence.

Agronomic evaluation of mungbean genotypes under delayed sowing conditions

High yielding varieties and suitable sowing time are the most important factors affecting the mungbean yield. Field experiments were carried out during kharif 2013 and 2014 at Dryland Agricultural Research Station, Budgam, Sher-e-Kashmir University of Agricultural Sciences and Technology Kashmir, India to find out the suitable genotype of mungbean under delayed sowing conditions. The early sowing (first fortnight of June) recorded higher yield contributing characters ( seeds/plant and 100 seed weight) and seed yield than delayed sowing. Among genotypes ‘SKUA-M-365’ recorded higher 100-seed weight and seed yield in early sowing as well as under delayed sowing conditions.

Determination of heavy metal pollution index of ground water of village Wallipur in Ludhiana district

The objective of the study was to reveal the seasonal variations in the groundwater quality with respect to heavy metals contamination near Buddha Nullah in Ludhiana district. To get the extent of trace metals contamination, groundwater samples from tube wells were randomly collected from 16 different points on both sides along the course of Buddha Nullah from areas of Bhamian Kalan, Khasi Kalan and Wallipur Kalan villages of Ludhiana district during first fortnight of June (Pre-monsoon), first fortnight of November (Post-monsoon) and first fortnight of January (Winter season) during the year 2013-14. The concentrations of toxic and heavy metals such as metalloids B, As, Pb; alkaline earth metals Mg, Ca; alkali metals Na, K; transition metals Cr, Mn, Fe, Cu, Zn, Cd and nonmetal S were determined. The heavy metal pollution index (HPI) was calculated. Most of the parameters were found within permissible limit of BIS, 2004. The average values of concentration of Ca, Cr, Mn, As and Pb for pre-monsoon season was higher than average concentration of post-monsoon and winter season. Overall HPI calculated based on the mean concentration of the heavy metals was found to be 18.11, 15.32 and 16.10 for pre-monsoon, post-monsoon and winter season, respectively, which was below the critical pollution index value of 100. The study recommended proper treatment to the sewage water which is being discharged into the Buddha Nullah.

Influence of Synchronization Techniques and Dates of Sowing on Nicking in Parental Lines of Pearl Millet Hybrid BPMH-3 Seed Production

The field experiment was carried out during Kharif 2016 at the Main Agricultural Research Station, to investigate the effect of staggered sowings and application of additional dose of nitrogen to late parent on synchronization of male and female parents of pearl millet hybrid BPMH-3. The field experiment comprised of twelve treatments with three replications in split plot design. The results revealed that staggered sowing of male parent nine days earlier than female (S4) took less number of days for panicle initiation, flower initiation and 50 per cent flowering in male. On the other hand simultaneous sowing of female and male parent (S1) recorded the lowest values for growth parameters and it took more number of days to panicle initiation, flower initiation and 50 per cent flowering. This revealed that sowing of male parent nine days earlier than the female parent and application of additional 10 kg N ha-1 to male parent at 35 days after sowing (S4) was appropriate to achieve nicking between female and male parental lines of pearl millet hybrid, BPMH-3. Another experiment was conducted at Saidapur farm, University of Agricultural Sciences, Dharwad, to study the flowering behaviour of TPRT 111 (male) and ICMA 9277 (female) parents of pearl millet BPMH-3 in periodical date of sowing with fifteen days interval from first June, 2016 to Second fortnight of December, 2016. The results revealed that the female (ICMA 9277) and male (TPRT 111) parental lines took significantly more number of days 52.00 days and 64.00 days respectively when sown during first fortnight of June 2016. While, less number of days was recorded by female and male parental lines (46.00 days and 51.00 days respectively) when sown during second fortnight of December 2016. Progressive decline in days to fifty percent flowering was observed with the advancement in the sowing which narrow down the flowering gap between male and female parental line.

Perpetuation of <i>Alternaria solani</i> of Potato under Temperate Kashmir Valley Conditions

The present study on perpetuation of Alternaria solani , causing early blight of potato in Kashmir valley was conducted during 2009 and 2010. The perpetuation of the fungus A. solani was studied on diseased leaves by placing the leaves on ground surface and at 20 cm depth, as well as on diseased potatoes kept in ambient store. The pathogen perpetuated as mycelium and conidia throughout winter on diseased leaves left on the ground surface and on diseased potatoes kept in ambient store. The number of spores cm -2 leaf area and the viability of spores decreased with increase in depth of placement in soil. Maximum spores production on over wintered leaves was observed during first fortnight of June during the year 2009 and 2010, with maximum number of 294 and 323 spores, respectively. However, by the first fortnight of July, the number gradually declined to 160 and 220 spores, respectively. The highest spore viability of 44.3 and 49.3 per cent in leaves on ground surface was recorded in the first fortnight of June, 2009 and 2010, respectively. In potatoes kept in ambient store the average number of spores increased upto first fortnight of June, both in 2009 and 2010, with a maximum number of 430 and 508 spores, respectively. The number then gradually declined to 216 and 263 spores, respectively, till last observation recorded in the second fortnight of July.

Evaluation of System of Rice Intensification (SRI) in rice (Oryza sativa) - groundnut (Arachis hypogaea) system under Island ecosystem

Field experiment was conducted during wet and dry seasons of 2007-09 at Field Crops Research Farm of Central Island Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands to evaluate System of Rice Intensification (SRI) in rice and its residual effect on groundnut in rice (Oryza sativa L.) – groundnut (Arachis hypogaea L.) systems. Time of planting, spacing and nitrogen practices evaluated significantly influenced the yield attributes and yield of rice, while the residual effect of N management practices had a positive influence on the yield attributes and yield of succeeding groundnut. Early planting in second fortnight of June with 20 cm × 20 cm spacing recorded higher panicles/m2 (9.1 %), higher number of filled grains/ panicle (108), higher grain yield (4 678 kg/ha), about 3% higher REY, productivity (26.8 kg/ha/day), and total profitability (` 62 882/ha) compared to the same time of planting with wider spacing (25 cm × 25 cm). Though application of 100% Recommended Dose of Nitrogen (RDN) through urea recorded highest grain yield (4 465 kg/ha) of rice, it was comparable with 50% RDN through Gliricidia + 50% RDN through urea and 75% RDN through Gliricidia + 25% RDN through urea. Application of 50% RDN through Gliricidia + 50% RDN recorded nearly 6% higher REY and ` 6 565/ha more profitability higher output energy in rice-groundnut sequence compared to application of 100% RDN through urea. N management practices of rice, in the crop sequence of rice- groundnut were found to improve the soil nitrogen status. Early planting of rice in second fortnight of June at 20 cm × 20 cm with the application of 50% RDN through Gliricidia + 50% RDN through urea can be recommended for achieving higher productivity, profitability and energy use efficiency of rice - groundnut system in Island ecosystem.

Effect of time of sowing and nitrogen fertilization on growth and yield of castor in vertisols under rainfed conditions

A field experiment was conducted at Regional Agricultural Research Station, Nandyal during kharif 2012 to study the effect of time of sowing and nitrogen fertilization on growth and yield of castor in vertisols under rainfed conditions. The experiment was laid out in a split-plot design with three replications. The treatments consisted of four main plots (Time of sowing - II fortnight of June, I fortnight of July , II fortnight of July and I fortnight of August and four sub plots (Nitrogen levels :0,40,60,80 Kg/ha). Significantly highest castor bean yield was recorded with I F.N. of July sowing but it was at par with II F.N. of June sowing. Significantly lowest castor yield was recorded with I F.N of August sowing. Irrespective of time of sowing, increase in N fertilization from 0 to 80 kg/ha increased the castor yield significantly, highest being with 80 kg N /ha. Interaction effect of I F.N of July sowing with 80 kg of N/ha recorded the highest yield but was at par with II F.N. of July sowing at the same level of N. I F.N of July sowing with 80 kg/ha of nitrogen application recorded the highest gross and net returns and B: C ratio.

Effect of Heading Back on Photosynthesis, Yield and Fruit Quality in Pear

A field study was conducted to examine the effect of heading back of pear plants on photosynthesis, yield and fruit quality in pear trees cv. ‘Patharnakh’. Plants were maintained at heights of 1.0 m, 1.5 m, 2.0 m, 2.5 m and 3.0 m from ground level by removing top of the canopy during dormant season, while the control trees were not given any pruning treatment. The photosynthesis rate (Pn) and photosynthetic active radiation (PAR) were taken from April to July at fortnightly interval. Highest Pn of leaves trees was observed at morning time and it showed a positive relationship with PAR received. Both increased with advancement in season and recorded maximum in the 2 nd fortnight of June, thereafter declined slightly. PAR and Pn increased with intensity of the pruning. Upper canopy of all the treatments recorded highest photosynthesis rate. Fruit yield per tree increased as the pruning height was raised and was recorded maximum in 2.5 m level of pruning. Fruit size enlarged linearly with the intensity of pruning. Pruning treatment improved soluble solids content of fruit.

Influence of Time of Planting, Spacing, Seedling Number and Nitrogen Management Practices on Productivity, Profitability and Energetics of Rice (Oryza sativa) in Island Ecosystem

Field experiments were conducted during wet season of 2007 and 2008 at Central Agricultural Research Institute, Port Blair, Andaman and Nicobar Islands in order to evaluate the practices of System of Rice Intensification (SRI) in Island ecosystem. Time of planting, spacing and nitrogen management practices significantly influenced the growth and yield attributes while number of seedlings/ hill did not exert any influence on these parameters. Planting in second fortnight of June with 20 x 20 cm spacing recorded higher number of tillers (18.3), DMP (17.6), panicles/m 2 (9.2) and filled grains/panicle (9.1). As a result of better growth and yield components, higher grain yield (4,678 kg/ha), net returns (Rs. 31,768/ha), net return per rupee invested (1.47) and energy ratio (14.5) were recorded in the early planting. Application of 100 % Recommended Dose of Nitrogen (RDN) through urea recorded more number of tillers with higher DMP, number of panicles, more number of filled grains and highest grain yield of 4,465 kg/ha but it was comparable with 50 % RDN through Gliricidia + 50 % RDN through urea and 75 % RDN through Gliricidia + 25 % RDN through urea. Though the net return was slightly higher (Rs. 29,002/ha) with application of 100 % RDN through urea, but net return per rupee invested was higher (1.40) with application of 50 % RDN through Gliricidia + 50 % RDN through urea. Thus, planting in second fortnight of June with 20 x 20 cm spacing using single seedling combined with application of 50 % N through Gliricidia and 50 % N through urea can be recommended for achieving higher productivity, profitability and energetic of rice in island ecosystem.