Aerobic Rice Cultivation Research Articles

Evaluating the Performance of Rice in Different Intercropping Systems under Aerobic Rice Cultivation

Evaluating the Performance of Rice in Different Intercropping Systems under Aerobic Rice Cultivation

Exploring drought mitigation options for improvement of physiology, yield and water use efficiency of aerobic rice (Oryza sativa)

An experiment was conducted during summer seasons of 2022 and 2023 in Wetland Farms at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu to mitigate the ill effects of moisture stress during the flowering stage of rice (Oryza sativa L.) by moisture stress mitigating chemicals. The trial was laid out in split plot design (SPD) with 3 main plots and 4 sub-plots, and replicated thrice. In main plot, irrigation at IW/CPE ratio 1.0 from emergence to physiological maturity (M1); withholding irrigation (drought stress) for 8 days from heading stage (M2); and withholding irrigation (drought stress) for 12 days from heading stage (M3) and in sub-plot drought stress mitigating chemicals, viz. no spray (S1); salicylic acid spray @100 ppm (S2); sodium selenate @20 ppm (S3); and pink pigmented facultative methylotrophs (PPFM) @1% (S4) were tested. Results revealed that irrigation at IW/CPE 1.0 from crop emergence to physiological maturity along with foliar spray of selenium @20 ppm at heading stage had beneficial impact on growth, physiological parameters, yield attributes and yield. Drought stress given for 8 days from heading stage with selenium spray recorded lesser detrimental effect on growth characters, yield attributes and yield when compared to drought stress given for 12 days from heading stage in aerobic rice cultivation. The yield reduction in drought stress for 12 days from heading stage with selenium @20 ppm spray and drought stress for 8 days from heading stage with selenium @20 ppm spray were 23.6 and 16.5% respectively, when compared to irrigation at IW/ CPE ratio 1.0 from crop emergence to physiological maturity with selenium spray @20 ppm. Water use efficiency and water profitability also increased by the application of stress mitigating chemical of sodium @20 ppm. From this study, it is recommended that, in aerobic rice cultivation if there is any drought occurrence during heading stage of crop, the selenium application @20 ppm can withstand drought even up to 8 days from heading stage.

Influence of coir pith application on soil moisture distribution with different irrigation regimes of aerobic rice (Oryza sativa) cultivation under trickle irrigation system

An experiment was conducted during the summers of 2019 and 2020 at the AICRP Water Management field, Tamil Nadu Agricultural University, Madurai, Tamil Nadu to study the effect of coir pith application on soil moisture distribution of aerobic rice (Oryza sativa L.) with different irrigation regimes. Treatment consisted of 3 irrigation regimes, viz. I1 , Trickle irrigation at 120% Pan Evaporation (PE); I2 , 100% PE, and I3 , 80% PE. Experiment separately, maintained the surface irrigation of IW: CPE 1.20 as control. The well-composed coir pith @375 kg/ha was spread over the raised beds and leveled well with surface soil. Soil samples were collected in vertical and horizontal directions for determining soil moisture by gravimetric method. Soil moisture appropriation was plotted graphically as contour maps used by the surfer. Results revealed that trickle irrigation at 120% PE with coir pith application improved the yield attributes of aerobic rice compared to surface irrigation (IW: CPE 1.20) owing to coir pith’s favourable hydrological and physical properties to hold and spread the water in the raised bed area.

Physiological, Agronomic, and Grain Quality Responses of Diverse Rice Genotypes to Various Irrigation Regimes under Aerobic Cultivation Conditions.

Aerobic rice cultivation represents an innovative approach to reduce water consumption and enhance water use efficiency compared to traditional transplanting methods. Simultaneously, cultivating drought-tolerant rice genotypes becomes crucial to ensure their sustainable production under abrupt climate fluctuations. Hence, this study aimed to explore the physiological, agronomic, and grain quality responses of ten diverse rice genotypes to various irrigation levels under aerobic cultivation conditions. A field experiment was performed for two summer seasons of 2019 and 2020 in an arid Mediterranean climate. The irrigation regimes were well watered (13,998 m3/ha), mild drought (10,446 m3/ha), moderate drought (7125 m3/ha), and severe drought (5657 m3/ha). The results revealed considerable variations among rice genotypes under tested irrigation regimes in all physiological, agronomic, and quality traits. According to drought response indices, rice genotypes were classified into three groups (A-C), varying from tolerant to sensitive genotypes. The identified drought-tolerant genotypes (Giza-179, Hybrid-1, Giza-178, and Line-9399) recorded higher yields and crop water productivity with reduced water usage compared to drought-sensitive genotypes. Thus, these genotypes are highly recommended for cultivation in water-scarce environments. Furthermore, their characteristics could be valuable in breeding programs to improve drought tolerance in rice, particularly under aerobic cultivation conditions. The PCA biplot, heatmap, and hierarchical clustering highlighted specific physiological parameters such as relative water content, chlorophyll content, proline content, peroxidase content, and catalase content exhibited robust associations with yield traits under water deficit conditions. These parameters offer valuable insights and could serve as rapid indicators for assessing drought tolerance in rice breeding programs in arid environments.

Growing Conditions and Varietal Ecologies Differently Regulates the Growth-regulating-factor (GRFs) Gene Family in Rice.

Growth-regulating factors (GRFs) are crucial in rice for controlling plant growth and development. Among the rice cultivation practices, aerobic methods are water efficient but result in significant yield reduction relative to non-aerobic cultivation. Therefore, mechanistic insights into aerobic rice cultivation are important for improving the aerobic performance of rice. This study aimed to examine the evolution of GRFs in different rice species, analyse the phenotypic differences between aerobic and non-aerobic conditions in three rice varieties, and assess the expression of GRFs in these varieties under both aerobic and non-aerobic conditions. This study comprehensively examined the GRFs gene family in 11 rice species (Oryza barthii, Oryza brachyantha, Oryza glaberrima, Oryza glumipatula, Oryza sativa subsp. indica, Oryza longistaminata, Oryza meridionalis, Oryza nivara, Oryza punctata, Oryza rufipogon, Oryza sativa subsp. japonica) focusing on phylogenetic analysis. Additionally, the expression patterns of 12 GRFs were investigated in three distinct genotypes of O. sativa subsp. indica rice, under both non-aerobic and aerobic conditions. Three major phylogenetic clades were formed based on conserved motifs in the 123 GRFs proteins in eleven rice species. Further, novel motifs were identified especially in O. longistaminata indicative of the species level evolutionary differences in rice. Among the trait performance, the number of tillers was reduced by ~ 36% under aerobic conditions, but the reduction was found to be less in CR Dhan 201, an aerobic variety. Besides, three GRFs namely GRF3, GRF4, and GRF7 were found to be distinct in expression between aerobic and non-aerobic conditions. Three GRF genes namely GRF3, GRF4, and GRF7 could be associated with the aerobic adaptation in rice.

Climate Smart Irrigation Practices for Improving Water Productivity in India: A Comprehensive Review

India, supporting 17% of the global population, from limited land (2.4% of the world's total) and freshwater resources (4%), faces severe water scarcity issues. The country experiences heightened challenges due to a monsoon climate leading to floods and droughts. Irrigation efficiency in India is 35-40% and irrigated area ~48.9%. To meet the demands of a large or growing population in limited land and water resources, climate-smart irrigation practices (CSIPs) are imperative. These practices not only increase yield but also precisely supply water, reduce water application volume, and enhance soil health under changing climate conditions. Precision water management technologies includes; advanced agro-techniques, micro-irrigation, conservation agriculture, crop diversification, integrated farming systems, and water harvesting. Micro-irrigation, encompassing drip and sprinkler systems, emerges as a critical solution for efficient water use. Techniques like Surface Drip Irrigation and Sub-surface Drip Irrigation (SSDI) not only save water but also enhance nutrient transport and reduce labor costs. The automation of micro-irrigation through sensors and wireless communication revolutionizes traditional practices, ensuring precise water management and boosting agricultural productivity. In addition, advanced agro-techniques, including laser land leveling, furrow-irrigated raised beds, aerobic rice cultivation, system of rice intensification, ground cover cum rice production system and Saguna rice technique have good potential to save water and improve water productivity. Implementing these advanced agro-techniques not only conserves water but also contributes to sustainable agriculture by improving overall water productivity, reducing environmental impact, and enhancing crop productivity. The integration of conservation agriculture (minimum soil disturbance, crop residue cover and crop diversification), integrated farming systems (combine diverse agricultural activities synergistically), and water harvesting is imperative for sustainable water management. This review paper systematically compiles climate-smart irrigation practices, including precision water management, combined with conservation agriculture, crop diversification, integrated farming systems, and water harvesting. This review paper offers researchers a comprehensive understanding of different CSIPs, assessing their impact on water conservation, increased crop and water productivity, and sustainability amid climate change. Farmers can gain practical understandings of CSIPs, while policymakers obtain essential information for addressing national water mission goals.

Effect of Arbuscular Mycorrhizal Fungi and Different Combination of Foliar Application of Nutrients on Nutrient Uptake and Yield of Aerobic Rice

Background: In Aerobic rice cultivation, crop would faces water and nutrient deficiency; it would be a difficult for roots to reach in those situation. During that stress situation VAM fungi helps to observe water along with essential nutrients results out of efficiently increases the nutrient uptake. Methods: The field experiment was conducted during 2022 at wetland farms, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore. The experiment consisted of thirteen treatments, which includes different recommended doses of VAM 50, 62.5 and 75 kg ha-1 together with different combinations of foliar application of 0.5% of urea, 0.5% of ZnSO4 and 1% of FeSO4. Conclusion: The experiment results concluded that the combined application of 150 % of recommended dose of VAM and foliar application of 0.5% urea + 0.5% of ZnSO4 + 1% of FeSO4 at 25 and 45 DAS, significantly increased the nutrient uptake, by improving the morphology of shoot and root biomass under upland condition.

Genetic Variation in Tolerance to Iron Deficiency among Species of Oryza

Transplanted rice cultivation has caused groundwater depletion in several regions globally. Direct-seeded rice under aerobic conditions is a water-saving alternative. However, under aerobic conditions, iron in the soil is oxidized from the ferrous to ferric forms, which are not easily available to rice crops, resulting in iron-deficiency-induced chlorosis (IDIC) and causing significant reductions in yield. Cultivated rice accessions have limited variations in IDIC tolerance, while the wild Oryza germplasm could be a potential source of IDIC tolerance. In this study, 313 Oryza accessions were evaluated for IDIC tolerance at the tillering stage under aerobic conditions and 20 IDIC-tolerant lines were identified. The twenty lines showed no signs of chlorosis and had high levels of iron content and SPAD values, while the eight cultivated controls exhibited varying degrees of chlorosis symptoms and low levels of SPAD and iron content. To confirm their tolerance, the selected lines were evaluated again in a subsequent year, and they showed comparable levels of tolerance, indicating that these lines were efficient in iron uptake and utilization, resulting in maintained high chlorophyll and leaf area index. These accessions may be useful for developing IDIC-tolerant cultivars for aerobic rice cultivation and future studies of the molecular basis of IDIC tolerance.

Influence of Rice Establishment Methods Affecting the Cooking Quality of Traditional Landraces in South India

Background: Rice is a staple food for half of the world population. Green revolution paved way for high yielding varieties and caused disappearance of traditional variety under cultivation. However, due to focus on nutritional benefits, the rice farmer’s sight have returned towards cultivation of traditional landraces. To evaluate this, the present research aim to study the cooking quality of various landraces under different water saving establishment methods. Methods: The field experiment was conducted during Samba 2021, in wetlands of Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu. The experiment was laid out in split plot design comprising four establishment methods as main plots viz. Aerobic rice (M1), Puddled transplanting (M2), Unpuddled transplanting (M3), Direct seeded rice (M4) with traditional landraces viz. Karuppu kavuni (V1), Mapillai samba (V2) and Seeraga samba (V3) in sub plots. Result: In this study physical characters like hulling and milling percentage, kernel length, breadth and length breadth ratio were analyzed along with the cooking qualities like kernel length and breadth after cooking, cooking time, linear elongation ratio, breadth expansion ratio, volume expansion ratio, solid loss, water absorption index and water solubility index. The puddled transplanting treatment recorded higher hulling and milling percentage of 4.5% and 5.8% than the aerobic rice cultivation. Among the landraces mapillai samba recorded kernel length and kernel breadth 8.20±0.06 mm and 2.78±0.02 mm respectively. The water absorption index and water solubility index was found to be higher in puddled transplanting treatment with 4.4% and 6.4% respectively than the aerobic rice treatment.

Arbuscular Mycorrhizal Fungi Response on Soil Phosphorus Utilization and Enzymes Activities in Aerobic Rice under Phosphorus-Deficient Conditions.

The prominence of arbuscular mycorrhizal fungi (AMF) in sustainable rice production has long been recognized. However, there is little information about AMF response in aerobic rice cultivation under phosphorus (P)-deficient conditions. The aim of this experiment was to compare and determine the preeminent AMF effects on rice mycorrhizal colonization, responsiveness, P utilization, and different growth-promoting traits under P-deficient conditions. Different AMF genera viz. (Funneliformis sp., Rhizophagus sp., Glomus sp., Acaulospora sp., and Claroideoglomus sp.) in four different aerobic rice varieties developed by ICAR-NRRI, India (CR Dhan 201, CR Dhan 204, CR Dhan 205, and CR Dhan 207) were investigated using the check P-susceptible variety (IR 36) and the P-tolerant variety (Kasalath IC459373). Data analyzed through linear modeling approaches and bivariate associations found that AMF colonization was highly correlated with soil enzymes, particularly fluorescein diacetate (FDA) and plant P uptake. The microbial biomass carbon (MBC) and FDA content were significantly changed among rice varieties treated with AMF compared to uninoculated control. Out of four different rice varieties, CR Dhan 207 inoculated with AMF showed higher plant P uptake compared to other varieties. In all the rice varieties, AMF colonization had higher correlation coefficients with soil enzymes (FDA), MBC, and plant P uptake than uninoculated control. The present study indicates that AMF intervention in aerobic rice cultivation under P-deficient conditions significantly increased plant P uptake, soil enzymes activities and plant growth promotion. Thus, the information gathered from this study will help us to develop a viable AMF package for sustainable aerobic rice cultivation.

Long-term impact of pulses crop rotation on soil fungal diversity in aerobic and wetland rice cultivation

Pulse crop rotation in rice cultivation is a widely accepted agronomic practice. Depending upon the water regime, rice cultivation has been classified into wetland and aerobic practices. However, no studies have been conducted so far to understand the impact of pulse crop rotation and rice mono-cropping on fungal diversity, particularly in aerobic soil. A targeted metagenomic study was conducted to compare the effects of crop rotations (rice-rice and rice-pulse) on fungal diversity in wetland and aerobic rice soils. Out of 445 OTUs, 41.80% was unknown and 58.20% were assigned to six phyla, namely Ascomycota (56.57%), Basidiomycota (1.32%), Zygomycota (0.22%), Chytridiomycota (0.04%), Glomeromycota (0.03%), and Blastocladiomycota (0.02%). Functional trait analysis found wetland rice-pulse rotation increased symbiotrophs (36.7%) and saprotrophs (62.1%) population, whereas higher pathotrophs were found in aerobic rice–rice (62.8%) and rice-pulse (61.4%) cropping system. Certain soil nutrients played a major role in shaping the fungal community; Ca had significant (p < 0.05) positive impact on saprotroph, symbiotroph and endophytes, whereas Cu had significant (p < 0.05) negative impact on pathotrophs. This study showed that rice-pulse crop rotation could enhance the saprophytic and symbiotic fungal diversity in wetland and reduce the population of pathogens in aerobic rice cultivation.

Response of varied rice genotypes on cell membrane stability, defense system, physio-morphological traits and yield under transplanting and aerobic cultivation

Aerobic rice cultivation progresses water productivity, and it can save almost 50% of irrigation water compared to lowland rice with the appropriate development of genotypes and management practices. Two field trials were conducted during 2020, and 2021 seasons to determine the validation of different rice varieties under aerobic cultivation based on their plant defense system, physio-morphological traits, stress indices, grain yield, and water productivity. The experiments were designed in a split-plot design with four replications. Two planting methods, transplanting and aerobic cultivation, were denoted as the main plots, and ten rice genotypes were distributed in the subplots. The results revealed that the planting method varied significantly in all measured parameters. The transplanting method with well watering had the highest value of all measured parameters except leaf rolling, membrane stability index, antioxidant, proline, and the number of unfilled grains. EHR1, Giza179 and GZ9399 as well as A22 genotypes a chief more antioxidant defense system that operated under aerobic conditions. Giza179, EHR1, GZ9399, and Giza178 showed high cell membrane stability and subsequently high validation under such conditions, and also showed efficiency in decreasing water consumption and improving water use efficiency. In conclusion, this study proves that Giza179, EHR1, GZ9399, Giza178, and A22 are valid genotypes for aerobic conditions.

Influence of land preparation on weed dynamics and growth of traditional rice landraces in the diverged location of Tamil Nadu

In recent years, traditional landraces are gaining importance due to its many health benefits. But the main drawback of the traditional rice variety is low productivity with increased water consumption. Therefore different rice establishment methods are to be evaluated. But weed infestation occurs in every establishment method. Hence the present study aimed to study the weed dynamics by evaluating the water-saving technologies compared with puddled transplanting using various landraces. The first field experiment was conducted during Samba (Aug-Sept) 2021 in the wetlands of Tamil Nadu Agricultural University, Coimbatore. The second field experiment was at the Research Station, Melalathur in Tamil Nadu during Navara (Nov-Jan) season 2021. The experiment was laid out in split plot design comprising four establishment methods as main plots viz. Aerobic rice (M1), Puddled transplanting (M2), Unpuddled transplanting (M3), Direct seeded rice (M4) with traditional landraces viz. Karuppu kavuni (V1), Mapillai samba (V2) and Seeraga samba (V3) in sub plots. In this study, weed dynamics like weed density and weed dry weight were recorded along with plant height, leaf area index and total chlorophyll content. Weed density and weed dry weight was 87.82 % and 74.63 % higher in aerobic rice cultivation than puddled transplanting method during all the observations in both experiments. On comparing the land establishment methods, Direct seeded rice performed well with 40.61% of higher plant height, 89.38 % of higher LAI, 38.48 % of increased total chlorophyll content than Aerobic rice cultivation. The landrace mapillai samba showed a significantly (p&lt;0.05) higher plant height of 64.09±7.14 cm, Leaf area index of 2.05±0.992 and total chlorophyll content of 2.56±0.461 mg/g of fresh leaf. Hence this study provides evidence that in the initial stage of rice cultivation, direct seeded rice and the mapillai samba landrace performed well than the other establishment methods and the other two landraces.

Decision Support Tool to Predict Panicle Initiation in Aerobic Rice

Aerobic rice cultivation offers the potential to reduce irrigated water use. A multitude of challenges, such as cold sterility, drought stress, and labor shortages, limit its adoption in temperate rice-growing regions. Increasing the duration and extent of soil moisture tension between irrigation events has been demonstrated to slow crop development. Delaying panicle initiation (PI) beyond the optimal window can expose rice to cold nighttime temperatures during the cold sensitive early pollen microspore, severely reducing yield. Tools to assist Australian temperate farmers and researchers in the irrigation management of aerobic rice to ensure PI occurs during the optimal window do not yet exist. Using data collected from an aerobic rice experiment conducted in temperate Australia in 2020–2021 and 2021–2022, a predictive model was built to assist in forecasting PI based on the timing of irrigation. Estimation of the area on an hourly basis of the cumulative evapotranspiration with rainfall subtracted from pre-emergent irrigation to PI, defined as the irrigation deficit integral, was used to account for the frequency, duration, and extent of soil moisture deficit between irrigation events. The relationship between the irrigation deficit integral and the number of days from pre-emergent irrigation to PI (R2 = 0.91) was used to build a model to predict PI with a root mean square error of 1.8 days for the validating data set. Furthermore, an example is provided of how the model can be used as a decision support tool to assist researchers and growers to schedule irrigation of aerobic rice to ensure PI occurs in a timely manner. This will increase the likelihood of high-yielding aerobic rice and may enhance the adoption of water-saving rice cultivation.

Varietal Improvement and Weed Management for Aerobic Rice Cultivation in the Drought-Prone Jharkhand State

Aerobic rice varietal and weed management trials under direct seeding were carried out at Birsa Agricultural University Rice Experimental Area, Kanke, Ranchi in the wet seasons of 2017 and 2018. Efforts were made to select better high-yielding varieties and improved production technology for aerobic rice cultivation. Dhaincha (Sesbania aculeata), Cowpea (Vigna unguiculata), and urd bean (Vigna mungo) were grown along with direct seeded rice, uprooted and used as a green mulch, 25 days after seeding. Six varietal trials were conducted under aerobic conditions during the 2017 and 2018 wet seasons in which the entries RP 6191-HHZ1-Y4-Y1-Y1 (6.90 t ha-1), PA 6129 (hybrid) (6.45 t ha-1), RP 6273-HHZ4-DT3LI1-LI1 (6.10 t ha-1), CR Dhan 201 (5.185 t ha-1), US 380(hybrid) (5.28 t ha-1), NVSR 2107 (4.73 t ha-1), IIRRH 124 (hybrid) (4.70 t ha-1) with early maturity were found promising. In varietal trials, intermediate plant height (100 to 110 cm), non-lodging and high yield (&gt;4.0 t ha-1) were major criteria for selection. Two to three irrigations were applied as per the requirement. Naveen variety under aerobic conditions produced maximum yield with 125 kg N per hectare in both years. Among weed control methods, rice+ dhaincha+ pre-emergence application of pendimethalin @ 0.75 g a.i. per hectare in 2017 and rice+ dhaincha+2,4 D @ 0.8 kg a. i. per hectare as post- emergence application produced maximum yield with weed control efficiency of 61.4% in 2018.

Effect of Soil Moisture Deficit on Aerobic Rice in Temperate Australia

Declining water availability is pressing rice growers to adopt water-saving irrigation practices such as aerobic rice to maintain profitability per megalitre (ML) of water input. Irrigators require well-defined irrigation thresholds to initiate irrigation to maximise water productivity. Such thresholds do not exist for temperate rice regions. Adopting a strategy that has been reported to succeed in non-temperate environments may fail in temperate climates, and therefore, needs investigation. This study aimed to investigate, in a temperate Australian environment, the effect of increasing soil moisture deficit during the rice vegetative period on crop physiological development, grain yield and water productivity. The study was conducted in a commercial farm using a randomised complete block design in the 2020/21 and 2021/22 growing seasons. Automated gravity surface irrigation technologies were adopted to enable high-frequency irrigation. Extending soil moisture deficit beyond 15 kPa was found to significantly delay panicle initiation by at least 13–14 days, exposing rice to cold temperatures in Year 1 during the cold-sensitive early pollen microspore period. This reduced yield by up to 55% (4.5 t/ha) compared to the 15 kPa treatment that was not impacted by cold sterility. In the absence of cold sterility, irrigated water productivity and total water productivity ranged between 1.02 and 1.61 t/ML, and 0.84 and 0.93 t/ML, respectively. The highest yields (8.1 and 7.5 t/ha) were achieved irrigating at a soil tension of 15 kPa in growing seasons 2020/21 and 2021/22. This research demonstrates that sound water productivity can be achieved with aerobic rice cultivation in temperate climates, providing cold temperatures during early pollen microspore are avoided. The quantification of the delay in crop development caused by increasing soil moisture deficit provides rice farmers greater confidence in determining the irrigation strategy and timing of pre-emergent irrigation in regions at risk of cold sterility. However, due to the high labour demand associated with aerobic rice, the adoption of aerobic rice at a commercial scale in this Australian environment is unlikely without adopting automated irrigation technology.

AEROBIC RICE'S YIELD PERFORMANCE AND NITROGEN USE EFFICIENCY UNDER VARIOUS NITROGEN FERTILIZER RATES

Aerobic rice, a water-saving cultivation system rice could thrive well in rain-fed areas in Sarawak which lacks in drainage and irrigation system, with appropriate fertilizer management practices. Since nitrogen (N) as a major determinant factor in rice yield is required differently based on cultivation system, soil and other in-situ conditions, a study was conducted to determine the optimum N fertilizer rate while assessing nitrogen use efficiency of aerobic rice in Lundu, Sarawak. Four N fertilizer rates (T1=0, T2=100, T3=200 and T4=300 kg N/ha) were tested with split application of urea (46% N) at 23%, 31%, and 46% at 5, 25, and 45 days after emergence (DAE) using MRIA1 variety. The findings indicated that an increase in N fertilizer of more than 100 kg N/ha had no discernible impact on yield. The highest yield recorded was 3.31 t/ha in T2 and decreased to 2.99 t/ha and 2.86 t/ha respectively in T3 and T4, while T1 recorded 1.12 t/ha. Meanwhile, significant differences in partial factor productivity (PFPN), agronomic efficiency (AEN), apparent recovery efficiency (REN) and physiological efficiency (PEN) were observed between the treatments with descending efficiency trends at higher N fertilizer rates. Optimum NUE values were recorded in T2 with PFPN = 29.30 kg/kg; AEN = 14.56 kg/kg; REN = 0.26 kg/kg; and PEN = 55.64 kg/kg. Therefore, it can be concluded that 100 kg N/ha is recommended for aerobic rice cultivation in Tanjung Purun, Lundu, as yield and NUEs were optimized.

Aerobic rice (Oryza sativa) cultivation under drip irrigation and fertigation system

A field experiment was conducted during the summer of 2019 and 2020 at the research field of (All Indian Coordinated Research Project on Water Management), Agricultural College and Research Institute, Madurai, Tamil Nadu, to assess the effect of drip irrigation and fertigation on aerobic rice (Oryza sativa L.) cultivation. The experiment was laid out in strip-plot design, replicated thrice. The irrigation was scheduled once in 3 days at 120, 100, and 80% pan Evaporation (PE), and the fertigation of 100, 75 and 50% recommended Dose of Fertilizer (RDF) was given weekly intervals from 15 days after sowing (DAS) to 70 DAS and the control of surface irrigation at an irrigation water: cumulative evaporation (IW : CPE) 1.25 with soil application of RDF (150 : 50 : 50 kg/NPK/ha) was separately maintained. The results of different irrigation and fertigation practices showed that, 120% PE × 100% RDF along with associated crop management had a significant effect on crop growth, yield and yield-contributing parameters and their values were significantly higher than all the other drip irrigation regimes and fertigation levels. This was mainly owing to continued availability of soil moisture and nutrients throughout the life period of aerobic rice, which led increased growth and yield parameters at the maximum level. Thus, 120% PE drip regimes and 100% RDF fertigation level proved better option in aerobic rice cultivation under drip irrigation and fertigation system in respect of yield and water saving.

Evapotranspiration of a Hungarian rice variety, ‘SZV Tünde’ in large weighing lysimeter

Aerobic rice production is an alternative growing method to reduce water consumption of rice and thus increase the water productivity of the system without a significant reduction of yield and quality. Evapotranspiration (ETc) of a Hungarian rice variety, ‘SZV Tünde’ under aerobic conditions was measured in large weighing lysimeter during the growing season in 2020. In our experiment, 506.7 g/m2 grain yield and a total above-ground biomass of 1140.4 g/m2 were produced with the application of 315.6 mm of irrigation. Water use-efficiency (WUE) based on the water input and the grain yield was 0.65 g/L. Total ETc for the whole season was measured as 648.3 mm. However, ETc values were ranged 2.04-3.86 mm/day, 3.57-7.90 mm/day and 0.90-4.26 mm/day at the initial, mid and end stages, respectively. Crop coefficients for the different periods of the season were calculated as Kcini=0.82, Kcmid=1.40 and Kcend=0.77. Negative effects of drought can seriously damage rice crop; therefore irrigation scheduling has significant role in successful aerobic rice cultivation. Reliable estimation of evapotranspiration rate in different crop developmental stages can promote this goal.

Effect of Brown Manuring and Different Levels of Nutrients on Growth and Yield Attributes of Aerobic Rice (Oryza sativa L.)

A field experiment was conducted during kharif season of 2019 to assess the Effect of brown manuring and different levels of nutrients on growth and yield attributes of aerobic rice (Oryza sativa L.) at Crop Research Centre, Dr Rajendra Prasad Central Agricultural University, Pusa, Bihar. This experiment was conducted in randomized block design (factorial) with sixteen treatment combinations replicated thrice using the rice variety “Abhishek” as a test crop which was planted with a spacing of 20 cm row to row, with the seed rate of 40 kg ha-1. The experimental results indicated that higher values of growth parameters viz. Plant height (109cm), tillers/m2 (355), dry matter production (969g/m2) and crop growth rate (12.2g/m2/day) were observed in rice + brown manuring treatment (B2) as compared to rice without brown manuring (B1) at harvest. While among the nutrient levels, treatment F8- 70 kg/ha phosphorous and 50 kg/ha potassium as split recorded significantly higher growth parameters (tillers/m2, dry matter production and crop growth rate), yield attributes (panicles/m2, grains/panicle), grain yield, while remaining at par with treatment F4 -60 kg/ha phosphorous and 50 kg/ha potassium as split. However, the interaction effect of both the factors did not significantly influence any of the parameters. Further the Aerobic rice cultivation save 40-45 per cent of water as compared to low land cultivation of rice.