Summer Rice Research Articles

Rice yield prediction through integration of biophysical parameters with SAR and optical remote sensing data using machine learning models

In an era marked by growing global population and climate variability, ensuring food security has become a paramount concern. Rice, being a staple crop for billions of people, requires accurate and timely yield prediction to ensure global food security. This study was undertaken across two rice crop seasons in the Udham Singh Nagar district of Uttarakhand state to predict rice yield at 45, 60 and 90 days after transplanting (DAT) through machine learning (ML) models, utilizing a combination of optical and Synthetic Aperture Radar (SAR) data in conjunction with crop biophysical parameters. Results revealed that the ML models were able to provide relatively accurate early yield estimates. For summer rice, eXtreme gradient boosting (XGB) was the best-performing model at all three stages (45, 60, and 90 DAT), while for kharif rice, the best-performing models at 45, 60, and 90 DAT were XGB, Neural network (NNET), and Cubist, respectively. The combined ranking of ML models showed that prediction accuracy improved as the prediction date approaches harvest, and the best prediction of yield was observed at 90 DAT for both summer and kharif rice. Overall rankings indicate that for summer rice, the top three models were XGB, NNET, and Support vector regression, while for kharif rice, these were Cubist, NNET, and Random Forest, respectively. The findings of this study offer valuable insights into the potential of the combined use of remote sensing and biophysical parameters using ML models, which enhances food security planning and resource management by enabling more informed decision-making by stakeholders such as farmers, policy planners as well as researchers.

Influence of Liquid Nano Urea Fertilizer on Growth and Yield of Summer Rice (Oryza sativa L.) under South Gujarat Conditions

A field experiment was conducted during summer season for two consecutive years (2022-2023) at Navsari, Gujarat to study the effect of liquid Nano urea fertilizer on summer rice (Oryza sativa L.) under South Gujarat conditions. The experiment was laid out in randomized block design with three replications and twelve treatments comprising T1: 100 % RDN (Recommended dose of nitrogen) through urea (120 kg N ha-1), T2: 75 % RDN + Seedling root dip in Nano urea at transplanting (TP) (4 ml L-1), T3: 50 % RDN + Seedling root dip in Nano urea at TP (4 ml L-1), T4: 25 % RDN + Seedling root dip in Nano urea at TP (4 ml L-1), T5: 75 % RDN + Spray of Nano urea at tillering stage (4 ml L-1), T6: 50 % RDN + Spray of Nano urea at tillering stag (4 ml L-1), T7: 25 % RDN + Spray of Nano urea at tillering stage (4 ml L-1), T8: 75 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T9: 50 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T10: 25 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1), T11: Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1) and T12: Seedling root dip in Nano urea at TP + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1). Application of 75 % RDN + Spray of Nano urea at tillering and panicle initiation stage (4 ml L-1) obtain significantly higher growth attributes viz., periodical plant height, number of tillers plant-1, dry matter accumulation plant-1, chlorophyll content and growth indices including leaf area index (LAI) at 60 and 90 DAS, crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) during 30-60 DAS, 60-90 DAS, and 90 DAS-Harvest. Similarly, significantly higher grain yield was produced under treatment T8 (4435 kg ha-1) which was 3.24% higher than 100% RDN through conventional urea.

Seedbed management, transplanting methods and irrigation regimes influence the growth, productivity and economics of summer rice (Oryza sativa L.)

A field experiment was conducted during the rabi (winter) seasons of 2017–2018 and 2018–2019 at the Central Research Farm under Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India, to study the effects of planting techniques, irrigation regimes, and nursery bed management on the growth, yield, nutrient dynamics, water productivity, and economics of summer rice (cv. Shatabdi) production. The experiment was performed in a strip-split plot design with twelve treatment combinations, which were replicated three times. The design consisted of two types of transplanted rice establishment methods (viz., puddled transplanted rice (PTR) and nonpuddled transplanted rice (NPTR)) allocated to the main plot, three irrigation regimes (three-day intervals; six-day intervals; nine-day intervals) allocated to the subplot, and two nursery bed management practices (conventional seedbed and improved seedbed) allocated to the subplot. Higher growth attributes, such as plant height, tiller count, biomass, and LAI, were found under nonpuddled conditions at the time of harvesting. Similarly, a three-day irrigation interval and improved seedlings led to better growth traits. The yield attributes and yield varied nonsignificantly among the crop establishment methods. However, the lowest irrigation intervals accounted for 53.78% and 43.02% greater grain yield than did the nine-day intervals in two consecutive years, respectively, and produced statistically similar yields with six-day intervals. The percentage of seedlings transplanted from improved seedbeds was 4.01 and 4.13% greater than that from conventional seedlings. A similar trend was observed for both input and irrigation water productivity, except that the nine-day irrigation interval resulted in significantly greater water productivity than did the other intervals. The treatment consisted of nonpuddled transplanted rice along with six six-day irrigation intervals and improved seedbed management, resulting in the highest net return and benefit:cost ratio due to the low production cost. Thus, it can be concluded that transplanting seedlings into nonpuddled soil from an improved seedbed with intermittent irrigation might be the most judicious and recommended in terms of productivity as well as profitability for summer rice production.

Assessing paddy methane emissions through the identification of rice and winter crop areas using Sentinel-2 imagery in Korea

The global efforts on reducing methane (CH4) emissions was emphasized in COP 28 and the potential for improved estimation became feasible through bottom-up data acquisition with advanced remote sensing technology. The objectives of this study were to extract summer rice and winter crop cultivation areas based on satellite images and to incorporate into estimating CH4 emissions in South Korea for the year 2020. Satellite images of Sentinel-1 and Sentinel-2 were acquired from European Space Agency. Rice paddy was classified with backscattering coefficient from Sentinel-1 images, while the normalized difference vegetation index from Sentinel-2 images was used to identify winter cropping field. The equation of IPCC guidelines was used to estimate CH4 emissions by incorporating the areas of rice paddy and winter crop extracted with the respective satellite image. National farming statistics were used to determine the scaling factors for paddy organic matter and water management practices. The estimated areas for rice paddy and winter crop cultivation were 712,237 ha and 117,840 ha, respectively. The rice paddy areas were primarily concentrated in the western regions of the Korean peninsula, whereas winter crop cultivation was predominantly found in southern part of the country. The total amount of CH4 emissions was 6272 Gg CO2 eq./yr when considering rice straw and winter cropping practices into estimation (modified Tier 2 method). This represents a 7% increase compared to the method that considered solely the rice straw incorporation (current Tier 2 method). The CH4 emissions per unit area were also 8.82 tons CO2 eq./ha/yr with the modified Tier 2 method, indicating a 10% greater compared to the current Tier 2 method. Substantial CH4 emissions were primarily concentrated in western regions where extensive rice paddy cultivation occurs, while greater CH4 emissions per unit area were predominantly found in southern regions with substantial winter crop cultivation. The study findings hold importance for improving the accuracy of CH4 emissions estimation by employing bottom-up approach that utilizes satellite imagery to assess rice paddy and winter cropping areas. Further study would be needed to incorporate field-based data on rice crop management practices, such as rice straw and water management, to further refine CH4 emission estimation method.

Estimation of greenhouse gas emission due to open burning of rice straw using Sentinel data

In recent decades, Vietnam has gradually become a critical global rice producer. During that production process, residual straw becomes an environmental pollutant due to open burning, raising greenhouse gas emissions. This study combines the optical images of the Sentinel-2 satellite and the radar images of the Sentinel-1 satellite to estimate the dry biomass of rice and to determine gas emissions due to rice straw burning over the fields in Quoc Oai district, Hanoi city for urban environmental management purposes. Sentinel-2 images have been classified into the land covers, thereby identifying the areas of ​​rice cultivation and the areas of ​​burned straw. Meanwhile, the Sentinel-1 radar image has been used to calculate the dry biomass of rice due to its ability to penetrate clouds, an obstacle to optical images in tropical regions. Furthermore, a field trip during harvesting season allows us to measure aboveground dry biomass. Then, the analysis shows a high correlation between the backscatter V.V. and V.H. of the radar image and the in-situ dry biomass (R=0.923 and R2=0.852), with a relatively low average error (RMSE = 6.58 kg/100 m2). By linear regression method, the study found the total rice dry biomass of 28728.5 tons, which was obtained after the Summer rice crop 2020 for the whole Quoc Oai district, of which 2037.91 tons of rice straw have been burned, releasing a large amount of greenhouse gas emission with 2398.6 tons of CO2, 189.5 tons of CO, 18.8673 tons of PM10 dust, 17.2087 tons of PM2.5 dust and some other gases. The identical procedure has also been applied to the western region of Hanoi city center to estimate the amount of gas emissions. This study has proven the effectiveness of an approach and contributed to supporting urban managers in proposing appropriate policies to monitor and protect the environment.

Crop establishment methods and herbicide mixtures induced weed dynamics, productivity, and profitability of summer rice

Rice farmers face challenges in achieving higher yield and profit during the summer season due to improper establishment and weed control. To address this, a study was conducted to assess the effects of herbicide combinations on the growth and yield of CR Dhan 206 (Gopinath), a high-yielding rice variety. The research took place from January to May 2022 at the PG Research Farm of M. S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha. The experiment followed a split plot design with two main plots (transplanted rice and wet seeded rice) and five subplots (fenoxaprop-p-ethyl + ethoxysulfuron (Tank mix) @ (50+15) g ha-1 at 18 days after transplanting/sowing (DAT/S); triafamone + ethoxysulfuron (Ready mix) @ (45+22.5) g ha-1 at 12 DAT/S; pretilachlor + bensulfuron-methyl (Ready mix) @ (600+60) g ha-1 at 4 DAT/S; weed-free (Hand weeding at 20,40,60 DAT/S); and weedy check) replicated thrice. The dominant weeds observed were Echinochloa colona, Leptochloa chinensis, Cyanotis auxiliaris, Physalis minima, Ludwigia parviflora, Cyperus iria, and Fimbristylis miliacea. Results indicated that the establishment methods did not significantly affect crop growth, yield attributes, crop yield, and weed infestation. However, the application of triafamone + ethoxysulfuron in both transplanted and wet seeded rice demonstrated superior growth, yield, weed control, and comparable results to the weed-free check. The combination of wet seeded rice and triafamone + ethoxysulfuron showed the highest net return and benefit-cost ratio, suggesting its recommendation for effective weed control and profitability in rice farming in summer season.

Multivariate Assessment of Groundwater Depletion and Recharge Prospect in a Sub-tropical Basin of Eastern India

Abstract The present study aims to highlight the groundwater-stress condition of the Quaternary 一 recent alluvial region escalated by anthropogenic extraction of water resources in the western Bengal Basin (Purba Bardhaman, West Bengal, India). With the rapid development of irrigation technology, high crop yield, water- consumed rice varieties, and high cropping intensity, the farmers of the river basin go to deeper underground aquifers (>180 m bgl) to extract water for summer rice (Boro) cultivation. In this study, the five semi-critical blocks (Mangolkote, Bhatai; Manteswai; Purbasthali II, and Memari II) of Purba Bardhaman district have experienced statistically significant pre-monsoon fall (0.404 m yr- 1 to 1.099 m yr-1) and post-monsoon fall of groundwater level from 0.486 m yr-1 to 2.214 m yr-1. Principal component analysis reflects that annual irrigation draft, annual replenishable groundwater unit, net groundwater availability, Boro rice cultivation area, area to be covered on each day irrigation for Boro, and daily pump discharge required for Boro irrigation are the key factors to escalate groundwater decline. This study reveals that Galsi II, Bardhaman I and II, Katwa I, and Purbasthali I blocks will experience a water-stress or groundwater drought in future. The model of groundwater recharge potential zone shows four principal categories of groundwater prospect area in the basin, viz., poor (0.08 %), moderate (5.78 %), good (68.96 %), and very good (25.18 %). These findings provide the relevant information for planners of groundwater resources to upscale groundwater management procedures and enhance the sustainability of agricultural systems in the study area.

Seasonal Incidence of Crambidae Pests on Summer Rice in Subtropical Madhya Pradesh

The production and productivity of rice is constrained by various insect pests but very meagre information is available on the seasonal incidence of the Crambidae pests of rice in the subtropical region of Madhya Pradesh. The present study was undertaken on the seasonal incidence of Crambidae pests at the Regional Agricultural Research Station, College of Agriculture, Balaghat, Madhya Pradesh during January -May, 2022. Rice variety JRB-1 was sown in a 300 m2 plot, damage of pests were recorded and correlated with the weather data. Stem borer damage manifested in the form of deadhearts and white ears, started from second fortnight of February and gradually increased till late April. Leaf folder incidence was observed from early March to early April. Incidence of these were found to be correlated positively with temperature and wind velocity whereas, negatively with relative humidity and rainfall. The pattern of incidence of these pests of rice in the subtropical region of central India (Balaghat, MP) were more or less similar to those of the tropics.

Sesame (Sesamum indicum L.): A Potential Allelopathic Crop - A Review

Sesame (Sesamum indicum L.) is one the oldest oilseed crop cultivated in India. It is cultivated as third crop in summer rice fallows or in marginal lands. Seeds of sesame are used for the extraction of oil, that contain many pharmaceutical and cosmetic properties. Research findings revealed that sesame contains many allelochemicals. The present review focuses on the allelopathic effect of sesame on weeds and crops. Exploring the allelopathic potential of sesame would help to develop bio-herbicides in future and reduce the use of synthetic herbicides in weed management. In addition to this, study on allelopathy of sesame would help to select suitable crops in rotation which are compatible to the sesame.

Summer Rice–Winter Potato Rotation Suppresses Various Soil-Borne Plant Fungal Pathogens

Growing potatoes (Solanum tuberosum) using the idle rice fields in Southern China and the Indo-Gangetic Plains of India in the winter season through the rice–potato rotation (RC) system could support future food security. However, the modulation capacity of the RC system on soilborne fungal pathogens is still unclear. In the current study, a pot experiment was designed and conducted to monitor the dynamics of soil fungal community composition between the potato monoculture (CC) system and the RC system, where the two systems were set with the same soil conditions: autoclaving with fertilization; autoclaving without fertilization; autoclave-free with fertilization; and autoclave-free without fertilization. Then, the uncultivated soil (CK) and root-zone soil samples of conditions under the two systems were collected, and then soil physiochemical properties and enzymatic activities were determined. Next, the high-variable region (V5–V7) of fungal 18S rRNA genes of the samples were amplified and sequenced through the PCR technique and the Illumina Miseq platform, respectively. Finally, the fungal species diversity and composition, as well as the relative abundance of fungal pathogens annotated against the Fungiuld database in soil samples, were also investigated. The results showed that the RC could significantly (p < 0.05) increase soil fungal species diversity and decrease the relative abundance of soil fungal pathogens, where the RC could suppress 23 soil fungal pathogens through cultivating the rice during the summer season and 93.75% of the remaining pathogens through winter-season cultivation. Seven-eighths of the conditions under RC have lower pathogenic MGIDI indices (6.38 to 7.82) than those of the CC (7.62 to 9.63). Notably, both rice cultivation and winter planting reduced the abundance of the pathogenic strain ASV24 under the Colletotrichum genus. The bipartite fungal network between the pathogens and the non-pathogens showed that the pathogenic members could be restricted through co-occurring with the non-pathogenic species and planting crops in the winter season. Finally, the redundancy analysis (RDA) indicated that soil pH, electronic conductivity, available phosphorus content, and various enzyme activities (cellulase, urease, sucrase, acid phosphatase, catalase, polyphenol oxidase) could be the indicators of soil fungal pathogens. This experiment demonstrated that the rice–potato rotation system outperformed the potato monoculture on suppressing soilborne fungal pathogenic community.

Evaluation of different fungicides against rice seedling rot incited by Sclerotium rolfsii Sacc.

Seedling rot disease in rice incited by Sclerotium rolfsii Sacc. in the rice nursery raised during December to January for summer rice cultivation is an emerging threat to rice cultivation in South Gujarat. In the present climate change scenario, rice crop is facing the challenges of new diseases which were otherwise not touching the economical threshold. Eight fungicides were evaluated under in vitro condition. Tebuconazole 50% + trifloxystrobin 25%, mancozeb 63%+ carbendazim 12%, azoxystrobin 18.2%+difenoconazole 11.4%SC, azoxystrobin 11.5% + mancozeb 30.0% and thiram 75 WS gave complete mycelial growth inhibition at 50 ppm concentration. Whereas azoxystrobin 23SC and tebuconazole 2% DS showed good mycelial growth inhibition ability with 83.30 and 90.74%, respectively. Most effective fungicides under in vitro were evaluated against seedling rot disease under field conditions during 2018 to 2020. Seed treatment with fungicides revealed that rice seeds treated with azoxystrobin 23SC @ 1ml /kg seed and soil application with Trichoderma harzianum (2×106 cfu/g) @ 1 g/m2 which was at par with seeds treated with azoxystrobin 23SC @ 1ml/kg seeds and azoxystrobin 18.2% + difenoconazole 11.4 %SC @ 1ml/kg seeds effectively managed seedling rot disease and given highest plant population with minimum seedling mortality, improved shoot and root length and good seedling vigor index.

Bioecology and Management of Major Insect Pests of Rice in West Bengal

West Bengal is considered a large producer state of rice in India with an output of nearly 55.48% of total crop production of Bengal. In West Bengal, rice has grown in three different cropping seasons such as Aus (autumn rice), Aman (winter rice) and Boro (summer rice), contributing about 20.69% to the total net State Domestic Product (SDP). Rice production in West Bengal hampered by many biotic stresses mostly by stem borers [Scirphophaga incertulas (Walker, 1863), Sesamia inference (Walker, 1856), Chilo polychrysus (Meyrick, 1932), Chilo suppressalis(Meyrick, 1863)] leaf folder [Cnaphalocrocis medinalis (Guenee, 1854)], plant hoppers [Nilaparvata lugens(Stal, 1854), Sogatella furcifera (Horvath, 1899)], leaf hoppers [Nephotettix virescens (Distant, 1908), Nephotettix nigropictus (Stal, 1870)], rice hispa [Dicladispa armigera (Olivier, 1808)], rice bugs [Leptocorisa acuta (Thunberg, 1783), Leptocorisa oratorius (Fabricius, 1794), Brevennia rehi (Lindinger, 1943)], gall midge [Orseolia oryzae (Wood-Mason, 1889)], etc. Demographic parameter has shown that rice pests are greatly affecting rice host either caused directly by creating dead heart (DH), hopperburn, onion leaf, silver shoot during different stages of harvesting or by indirectly transmitting grassy stunt virus (RGSV), rice ragged stunt virus (RRSV), rice tungro viruses (RTV), rice tungro bacilliform virus (RTBV) etc. resulting 9.5% production loss. For minimize the infestation farmers use different rice varieties which provide resistance effect in pest population. For controlling rice pest population farmers mostly use chemical insecticide [e.g. fipronil, acephate, fipronil, monocrotophos] which exhibit good results against rice pests. Beside those other techniques including using biological and biochemical pesticides [neem oil, karanj oil, mahua oil, conidial suspension of M. anisopliae], pheromones [(Z)-11-hexadecinal, (Z)-9-hexadecenal], allomones [5: 1 mixture of 2-(E)-octenyl acetate and octanol 3-octenal], cultutal methods [synchronized planting, using of trap crop etc.] are effective for controlling rice pests. The population ecology based sustainable management of such pest species will support E 3 strategy [Ecosystem service-based ecological engineering for ecological pest management (ESS-EE-EPM)] of pest management for successful cultivation of rice in the near future.

Discrimination and monitoring of rice cultural types using dense time series of Sentinel-1 SAR data

Details about the spatial extent of rice cultivation in different seasons are essential for ensuring global food security as well as addressing environmental issues and climate change. This study aims to introduce a novel approach to discriminate between different rice cultural types and subtypes and identify their optimum stages to represent crop growth profiles using Synthetic Aperture Radar (SAR) data. Dense time series Sentinel-1 SAR backscatter data were analyzed at 12 days intervals throughout the growth period of summer and kharif rice. Statistical analysis using ANOVA at 5% level of significance was conducted to identify the critical stages of discrimination for all cultural types and subtypes. Knowledge-based decision tree algorithm was employed to classify all major types of rice grown during summer and kharif season. A comprehensive analysis revealed significant variations in backscatter profiles among different rice types. The most critical period for effectively distinguishing between various rice cultural types and subtypes was found to be from transplanting to tillering stage. Decision tree algorithm was able to discriminate between rice cultural types and subtypes with high overall accuracy and Kappa coefficient, viz., 94.74% and 0.94 for summer rice and 91.80% and 0.90 for kharif rice, respectively. The findings of this study revealed that C-band co and cross-polarized Sentinel-1 data have the potential to detect differences between different cultural types and subtypes of rice and, therefore, will be helpful in crop growth monitoring and agro-ecological change detection in the cultivation pattern.

Rising surface ozone due to anthropogenic activities and its impact on COVID-19 related deaths in Delhi, India

The rapidity and global spread of the COVID-19 pandemic have left several vital questions in the research community requiring coordinated investigation and unique perspectives to explore the relationship between the spread of disease and air quality. Previous studies have focused mainly on the relation of particulate matter concentration with COVID-19-related mortalities. In contrast, surficial ozone has not been given much attention as surface ozone is a primary air pollutant and directly impacts the respiratory system of humans. Hence, we analyzed the relationship between surface ozone pollution and COVID-19-related mortalities. In this study, we have analyzed the variability of various atmospheric pollutants (particulate matter (PM2.5 and PM10), Nitrogen dioxide (NO2), Carbon monoxide (CO), and Ozone) in the National Capital Region (NCR) of India during 2020–2021 using station data and investigated the relationship of the air-quality parameters with the COVID-19 related deaths. In northern parts of India, the concentration of particulate matter (PM2.5 and PM10), Nitrogen dioxide (NO2), Carbon monoxide (CO), and Ozone remain high during the pre- and post-monsoon seasons due to dust loading and crop residue burning (after winter wheat in April & summer rice in November). The westerly wind brings the polluted airmass from western and northwestern parts to Delhi and National Capital Region during April–June and October–November, and meteorological conditions help raise the concentration of these pollutants. Due to long solar hours and high CO concentrations, the ozone concentration is higher from April to June and September. While comparing major air quality parameters with COVID-19-related deaths, we found a good relationship between surface ozone and COVID-19 mortality in Delhi. We also observed a time lag relationship between ozone concentration and mortality in Delhi, so the exposure to Ozone in a large population of Delhi may have augmented the rise of COVID-19-related deaths. The analysis suggested that ozone has a significant relationship with COVID-19 related mortality in Delhi in comparison to other parameters.

Field Assessment of Strip-Tillage for Summer Rice Cultivation in Bangladesh

Farmers in the tropics and subtropics of Asia usually transplant rice seedlings in puddled soils which makes crop establishment and weed control easier. But rice can be grown successfully by planting into non-puddled soils after a single shallow pass of strip tillage. This method was globally reported to produce the same yield of rice as traditional puddle farming and saved labor, fuel and water, too. With this aim to asses the effect of strip tillage in the productivity of rice in Bangladesh, a trial was done at a farmer's field in the Gauriopur area of Mymensingh district in Bangladesh from July to December 2014. The productivity of four summer rice varieties, BR11, BRRI dhan46, BRRI dhan52, and BINA Dhan-7, was compared under strip tillage (ST) vs. conventional tillage (CT). The CT had two main ploughings done by a two-wheel tractor, and the ST was done in a single pass by a Versatile Multi-crop Planter. The interactive results of study showed that, except for the number of effective tillers per m2, grain yield, and BCR, none of the other parameters changed significantly between the treatments. The highest BCR profit came from BR 11 grown under ST, followed by BRRI dhan52, BRRI dhan46, and BINA Dhan-7 grown under ST. The lowest BCR was measured from BINA Dhan-7 grown under CT. This could be because the highest and lowest amount of effective and sterile tillers and the maximum grain yield were seen in the respective treatments. The ST had a 26% higher BCR than the CT, which could have been due to the 3% higher grain yield that came from having 6% more effective tillers and 42% lower sterile tillers per m2 area. In the end, we could say that ST is a more profitable way to grow rice than CT, and BR 11 is the best of the other three types.

Effect of different nano-fertilizer on growth and yield of summer rice

In the developing world rice (Oryza sativa L.) is the most important cereal crop and it is the staple food of over half of the world’s population. More than 90% of rice is produced and consumed in Asia. Extensive use of chemical fertilizers causes a great alteration in soil physiology and reduce the soil fertility, damages the flora and causes soil erosion and reduce NUE (Nutrient Use Efficiency). A field experiment was conducted in the year 2019-20 in summer rice at the institutional farm, Jaguli, B.C.K.V, Nadia, West Bengal on “Effect of different nano-fertilizer on growth and yield of summer rice” to study the effect of nano-fertilizers on growth, yield and yield components of summer rice. In case of plant height and dry matter accumulation (g/m2), the highest value was observed in T8 treatment (50% Recommended dose of Zn + 100% N - P - K+ Foliar application of Nano Zn). In LAI also the same trend follows as like DMA. Maximum grain yield and straw yield was recorded from T8 treatment (5.61 t/ha and 6.18 t/ha respectively) followed by T9 treatment. It was observed that highest B:C ratio was also seen in T8 treatment followed by T9 and T3 treatment. From the economic analysis of different treatments, it was observed that highest B:C ratio was seen in T8 treatment followed by T9 and T3 treatment. So, T8 treatment is beneficial in economical aspect also.

Zero Till Water Use Efficient Rabi Sorghum (Sorghum bicolour L. Moench), an Effective Alternative to Water Guzzling Summer Rice (Oryza sativa), under Changing Climatic Scenario

As temperature rises, the yields of food and cash crops in South Asia are expected to decline, putting pressure on food security in the region. India, home to 1.4 billion people, is ranked 101 out of 116 countries in the Global Hunger Index, indicating a serious problem. Scientists and researchers project that a 2.5 to 4.90C increase in temperature across the country could lead to a decrease of 41%-52% in the wheat yield, and 32%-40% in rice. Under changing climate conditions, hybrid sorghum is an effective solution for food security, which can withstand high temperatures and grow with less water over water guzzling summer rice. It has versatile utility as food grains, feed, fodder, and an important feedstock for first-generation biofuel or bioethanol production. Zero till hybrid sorghum cultivars CSH 14, CSH 16, and CSH 23 were sown after Kharif rice in jute-rice-Rabi sorghum sequence, in winter, on 1st January 2010. The crop matured with 52.5 cm irrigation water at 120 days (30th April) and consumed 7 irrigations, 7.5 cm each. The highest sorghum grain yield was obtained from cv. CSH 14 i.e., 6.5 tonnes/ha. Its water productivity was high, 808 litre water/kg grain whereas for summer rice with the same productivity (6.5t/ha) the water productivity was low, 2308 litre water/kg rice grain (irrigation requirement 150 cm). Thus, with the same water, the area under sorghum will be thrice over summer rice. Gross return from hybrid sorghum was Rs.193050/ha over Rs. 132600/ha from summer rice. Rabi sorghum saved 65% (97.5 cm/ha) of irrigation water which is drawn from groundwater only. From 6.5 tons of sorghum grain, approximately 2470 litre of ethanol can be produced/ha which is used as biofuel. Replacement of summer rice by profitable drought-resistant Rabi sorghum will ensure food security under changing climatic scenarios and maintain a sustainable groundwater position in traditional rice growing belts.

Growth, Yield and Grain Arsenic Concentration of Rice Cultivars under Varying Levels of Soil Arsenic Contamination

Arsenic (As) contamination in groundwater is a severe and widespread problem in Bangladesh and their exposure cause a serious health hazard in human history. A pot experiment was conducted in the net-house of the Department of Soil Science, Bangladesh Agricultural University, Mymensingh using fourteen cultivars of rice (Summer rice) to evaluate the effects of varying levels of As contamination on growth, yield and grain As contents. Arsenic contamination adversely affected tillering, filled grains, grain yield and straw yield of all rice cultivars, however, the effect varied among the cultivars. In As control treatment, the highest grain yield (75.66 g pot-1) was observed in BR 11 while the lowest grain yield (8.73 g pot-1) was in BRRI dhan4. Application of 20 ppm As to the soil resulted in complete death of BR 11, BRRI dhan30, BRRI dhan33, BRRI dhan34, BRRI dhan41, Binadhan-4, Biroy and Kalizeera cultivars. Arsenic contamination significantly increased As concentration in grain for all cultivars of rice. Arsenic concentration on rice grains grown in soils without As contamination ranged from 0.06 ppm in BR 11 to 0.13 ppm in BRRI dhan32 and BRRI dhan41, while such values ranged from 0.231 ppm in Kalizeera with 10 ppm As to 0.743 ppm in BRRI dhan40 with applied 20 ppm As to soils. Among the 14 rice cultivars BRRI dhan32, BR 11 and Najirshail appeared to be more tolerant to As contamination.

Ecosystem carbon dioxide exchange and water use efficiency in a triple-cropping rice paddy in Southern India: A two-year field observation

The lowland tropical triple-cropping rice system has unique characteristics that affect the hydrological, nutrient, and atmospheric environments. To better understand the ecosystem carbon and water dynamics of a triple-cropping rice paddy from the perspective of sustainability, ecosystem-level CO2 flux and ecosystem water use efficiency (eWUE) were observed using eddy covariance over 2 years (2016–2018) at an experimental field site in southern India, and gross primary production (GPP) and ecosystem respiration (RE) were derived using the flux partitioning technique. Results showed that among the three crop seasons per year, GPP and RE were higher (887.2 and 570.2 g C m−2, respectively) in Thaladi (October–January: wet season) than in Kuruvai (June–September: dry season; 773.4 and 568.9 g C m−2, respectively) and summer rice (February–May; 694.0 and 499.7 g C m−2, respectively) owing to the longer growing season. Triple-cropping meant that the quasi-annual GPP of 2598 g C m−2 (i.e., the total value for the three consecutive seasons, including the corresponding fallow periods) was much greater than the quasi-annual RE of 1974 g C m−2. Consequently, the net ecosystem production value was positive (624 g C m−2). Evapotranspiration was also high on the annual scale (1681 mm); that is, 48 % greater than mean annual precipitation (1139 mm). Analysis revealed that Thaladi had higher eWUE (2.21 g C (kg H2O)−1) than that of Kuruvai (1.46 g C (kg H2O)−1) and summer rice (1.57 g C (kg H2O)−1) owing to decreased water loss in cloudy weather. Intense solar radiation is generally recognized as advantageous for crop growth in most regions, but not for Kuruvai and summer rice, when too strong solar radiation increases loss of water unused for photosynthesis. The findings indicate that water-saving techniques should be targeted on the Kuruvai and summer rice seasons.

Adapted Conservation Agriculture Practices Can Increase Energy Productivity and Lower Yield-Scaled Greenhouse Gas Emissions in Coastal Bangladesh

While numerous studies have documented the benefits of conservation agriculture (CA) in South Asia, most focus on favorable environments where farmers have reliable access to energy supporting irrigation and inputs. The performance of CA in South Asia’s under-developed coastal environments is comparatively understudied. In these environments, farmers are increasingly interested in growing a second crop to meet food security and income generation objectives in rotation following the predominant monsoon season rice crop, though labor, energy costs, and investment constraints limit their ability to do so. We hypothesized that rotating rice (Oryza sativa) with maize (Zea mays) using conservation agriculture, or CA (i.e., strip-tilled maize followed by unpuddled transplanted rice), or seasonally alternating tillage (SAT, i.e., strip-tilled maize followed by fully-tilled, puddled rice with residues retained across rotations) would reduce costs and energy use, increase energy-use efficiency, and reduce yield-scaled CO2-eq emissions (YSE) and total global warming potential (GWP), compared to farmers’ own practices (FP) and conventional full-tillage (CT) under the same rotation in Bangladesh’s coastal region. Starting with winter maize followed by summer rice, we evaluated four tillage and crop establishment treatments in farmer-managed experiments in partially irrigated and rainfed environments over three years in 35 farmer’s fields across Bangladesh’s coastal districts. Treatments included FP, CT, complete CA, and SAT under a rice-maize rotation. Across years, the full suite of CA practices and SAT were significantly more energy-efficient and energy-productive than FP or CT. The order of YSE in rice was CA< CT or FP < SAT while in maize, it was CA or SAT < FP < CT. Across environments, CA and SAT resulted in 15-18% higher yield at the cropping systems level (maize and rice yields combined) and 26-40% less manual labor than CT or FP. CA and SAT also reduced by 1-12% and 33-35% total production costs respective to CT and FP. This was associated with 13-17% greater grain energy output in CA and SAT, and 2-18% lower YSE, compared to CT or FP. While our data suggest that both CA and SAT can result in a range of positive agronomic, economic, and environmental outcomes compared to FP or CT, post-trial surveys and discussions with farmers revealed a strong practical aversion to use of the full suite of CA practices and preference for adapted practices due to logistical constraints in negotiating the hire of laborers for unpuddled manual transplanting.