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The adverse impact of climate change on crop yield has accelerated the need for identification of crop cultivars resistant to abiotic stress. In the present study, a cultivar assortment index (CAI) was generated for the evaluation of forty Amaranthus hypochondriacus cultivars response to elevated ozone (EO) concentrations (AO + 30 ppb) in Free Air Ozone Enrichment (FAOE) facility using the parameters viz. foliar injury, gaseous exchange attributes, namely, net photosynthetic rate, stomatal conductance, transpiration rate, intercellular carbon dioxide, and water use efficiency along with above ground biomass and grain yield attributes. The dataset was used to identify key indicator parameters responsive to EO through principal component analysis (PCA) and further transformed to obtain linear score and weighted score. The CAI varied from 70.49 to 193.43. Cultivars having CAI value less than 151 were ozone tolerant (OT) whereas cultivars with CAI values between 150 and 170 were moderately tolerant (MOT). The cultivars exhibiting CAI values above 170 were ozone sensitive (OS). The cultivars exhibited differential sensitivity to EO with IC-5994 (CAI = 187.26) being the most affected cultivar whereas IC-5576 (CAI = 83.38) and IC-5916 (CAI = 70.49) being the least affected ones. The CAI, based on linear score and weighted score, offers easy identification of ozone sensitive (OS) and ozone tolerant (OT) cultivars. This index could help researchers to define a clear and strong basis for identification of OT cultivars which will reduce the time required for preliminary screening and further evaluation of crop cultivars for the development of climate smart crops.

Nitrogen (N) fertilizers are widely used worldwide to increase agricultural productivity. However, significant N losses contributing to air and water pollution ultimately reduce the nitrogen use efficiency (NUE) of crops. Numerous research studies have emphasized the use of a low dose of N fertilizer, but few have focused on screening N-efficient rice genotypes. This study aimed to identify and screen ten rice genotypes that are N-use-efficient under different N fertilization treatments using the surface placement of neem-oil-coated urea: N0 (control), N60 (½ of recommended N), and N120 (recommended N) for two consecutive years (2020 and 2021) under a split plot design. In both growing seasons, the application of N120 yielded the highest panicles m−2 (PAN = 453), filled grains panicle−1 (FGP = 133), leaf area index (LAI = 5.47), tillers m−2 (TILL = 541), grain yield t ha−1 (GY = 5.5) and harvest index (HI = 45.4%) by the genotype ‘Nidhi’, being closely followed by the genotype ‘Daya’. Four genotypes (‘Nidhi’, ‘Daya’, ‘PB 1728’ and ‘Nagina 22’), out of the ten genotypes evaluated, responded well to different fertilization treatments with N with respect to the grain yield efficiency index (GYEI ≥ 1). Regarding N fertilization, N60 and N120 recorded the highest increase in PAN (28.5%; 41.4%), FGP (29.5%; 39.3%), test weight (29.5%; 45.3%), LAI at 30 days after transplanting (DAT) (143.7%; 223.3%), and LAI at 60 DAT (61.6%; 70.1%) when compared with N0. Furthermore, the application of N60 and N120 improved GY and HI by 47.6% and 59.4%, and 3.4% and 6.2%, respectively, over N0. Nitrogen addition (N60 and N120) also significantly increased the chlorophyll content at 60 DAT (8.8%; 16.3%), TILL at 60 DAT (22.9%; 46.2%), TILL at harvest (28%; 41.4%), respectively, over N0. Overall, our research findings clearly indicate that ‘Nidhi’ and ‘Daya’ could be efficient candidates for improved nitrogen use, grain yield and GYEI in the Indo-Gangetic plains of India.

Climate change affects nitrogen dynamics in crops and diazotrophic microorganisms with carbon dioxide (CO

Healthy soils are the foundation for producing healthy food and creating a healthy environment. Therefore, we assessed the changes in the physical and chemical properties of soil, and their long-term impact on yield, quality, and nutritional status of rice grains in an organic basmati rice-based cropping system in a typic Ustchrept Soil of India. The experiment was laid out in a strip plot design with three replications. The vertical strips consisted of two rice-based cropping systems, namely, basmati rice-wheat-mung bean (RWM) and basmati rice-wheat-sesbania (RWS), whereas seven combinations of different organic materials and biofertilizers (BF) were assigned to horizontal strips, viz., control (no manure application), farmyard manure (FYM), vermicompost (VC), FYM + crop residues (CR), VC + CR, FYM + CR + BF, and VC + CR + BF. The results revealed that soil moisture content (SMC), soil organic carbon (SOC), soil total N, and soil available P, Fe, Zn, Mn, and Cu were significantly higher under the RWS system than in RWM. The application of organic manures either alone or in conjunction with CR and BF significantly lowered the soil pH (∼3.0%), EC (43.1%–45.8%), and BD (3.3%–9.2%) as compared to the control. Water holding capacity (WHC), SMC, and SOC were increased by 5.7%–14.7%, 8.7%–49.3%, and 35.3%–76.5%, respectively under single or co-application of FYM/VC with CRs and BFs as compared to control. Similarly, sole or conjoint application of organic manures, CR, and BF significantly enhanced the soil available macro (N, P, and K) and micro (Fe, Zn, Mn, and Cu) nutrients over the control. Grain yield, protein content, N uptake, and cooking quality parameters were significantly higher under the RWS system than under RWM. However, the Zn concentration and its uptake by grains were significantly higher under the RWM system over RWS. The grain yield was significantly increased by 25.8%–49.2% under different organic nutrient management options over control. The single or conjoint application of FYM/VC with CR and BF increased the hulling, milling, head rice recovery, and protein concentration in grain by 9.4%–9.8%, 23.2%–28.4%, 22.7%–25.5%, and 9.6%–10.7%, respectively over control. The concentration of N, P, K, Fe, Zn, Mn, and Cu was significantly improved by 9.7%–11.3%, 45.5%–63.6%, 16.7%–20.8%, 66.9%–74.1%, 72.9%–81.9%, 87.1%–97.0%, and 48.9%–67.2%, respectively under co-application of FYM/VC with CR and BF compared to control. Thus, our results indicate that improved soil properties could significantly increase the physical and nutritional quality of basmati rice grain. Therefore, adopting basmati rice-based cropping systems with different organic nutrient sources can sustain soil health, end global hunger, produce nutritious food, and create a healthy environment.

Delayed sowing of maize hybrids could exacerbate the capability of maximizing the yield potential through poor crop stand, root proliferation, nutrient uptake, and dry matter accumulation coupled with the inadequate partitioning of the assimilates. This study appraised the performance of five recent maize hybrids viz., PMH-1, PJHM-1, AH-4158, AH-4271, and AH-8181 under timely and late sown conditions of the irrigated semi-arid ecologies. Timely sowing had the grain and stover yields advantage of 16–19% and 12–25%, respectively over the late sown maize hybrids. The advanced hybrids AH-4271 and AH-4158 had higher grain yields than the others. During the post-anthesis period, a greater dry matter accumulation and contribution to the grain yield to the tune of 16% and 10.2%, respectively, was observed under timely sown conditions. Furthermore, the nutrient acquisition and use efficiencies also improved under the timely sown. The nutrient and dry matter remobilization varied among the hybrids with AH-4271 and PMH-1 registering greater values. The grain yield stability index (0.85) was highest with AH-4158 apart from the least yield reduction (15.2%) and stress susceptibility index (0.81), while the maximum geometric mean productivity was recorded with the AH-4271 (5.46 Mg ha−1). The hybrids AH-4271 and PJHM-1 exhibited improved root morphological traits, such as root length, biomass, root length density, root volume at the V5 stage (20 days after sowing, DAS) and 50% flowering (53 DAS). It is thus evident that the timely sowing and appropriate hybrids based on stress tolerance indices resulted in greater yields and better utilization of resources.

Irrigation is one of the largest consumers of fresh water in the agricultural sector. Surface irrigation is one the most widely adopted method of irrigation due to its simplicity and low energy requirement. Although, it is mostly associated with poor irrigation application efficiency mainly due to deep percolation and uneven distribution of irrigation water. A study was conducted in closed-end level basin layout in loamy soil to establish and test an Internet of Things (IoT) based system through a wireless connection between the automatic check gate and soil moisture sensors which can be operated remotely based on real-time soil moisture status. An attempt had been made to identify the suitable location of the sensor in the basin layout for improving irrigation application efficiency. An aluminium automatic-check gate fitted in an iron frame was placed in the concrete water supply channel to control the water flow. Three capacitance-based soil moisture sensors were placed at 25%, 50% and 75% of field length (i.e., 15 m, 30 m and 45 m) at 37.5, 15 cm and 7.5 cm depth, respectively. A wireless communication network was established between capacitance-based soil moisture sensors and an automatic check gate through the LoRa module and GSM module. The software used for automatic control of the check gate in this study was Croplytics® by Agsmartic. The system was tested for nine irrigation events under bare soil conditions. Three different operational schedules based on different soil moisture sensor placement had been tested under 40%, 30% and 20% soil moisture deficit conditions. The results suggested that the best location of sensors for closing the system would be at 37.5 cm depth placed at 25% length from the inlet in higher soil moisture deficit condition and at 7.5 cm depth placed at 75% length in low moisture deficit condition. Overall, the irrigation application efficiency was improved up to 86.6% with automation.

Potential methane-oxidizing-plant growth-promoting yeast was isolated and characterized during 2017-18 at the ICAR-Indian Agricultural Research Institute, New Delhi. Yeast isolates belonging to the genus Meyerozyma guilliermondii were isolated from five major flooded paddy growing regions of India. Among all the isolates, Meyerozyma guilliermondii KAS-143 efficiently oxidized methane up to 57.64% ± 0.83 in 6 d under in vitro conditions. It also produced a significant quantity of phytohormone IAA and solubilized P, K, and Zn. Meyerozyma guilliermondii KAS-143 can be used for devolving potential inoculants for flooded paddy which can not only promote plant growth but also simultaneously reduce methane emission by its oxidation.

A pragmatic approach has been chosen to assess the risk of arsenic (As) in the water-soil-plant-human continuum in an arsenic-prone area of Nadia district in West Bengal. Arsenic is a dangerous carcinogen, and people’s exposure to As via rice consumption is widely recognized. For this purpose, 201 paired soil and rice grain samples were collected from the main rice-producing agricultural field in West Bengal and analysed for their pH levels, organic carbon, extractable As, and As content in rice grain. Olsen extractable As concentration varied from 0.48 to 3.57 mg kg− 1 with a mean value of 1.45 mg kg− 1. Rice grain samples contained As in the 0.20 to 0.61 mg kg-1 range while the mean value was 0.43 mg kg− 1. The hazard quotient for As intake via human consumption is due to the rice grain varying between 0.27 to 0.83. Lifetime cancer risks related to As intake through drinking water and dermal intake were 1.0 × 10− 3 and 4.23× 10− 5, respectively, yielding a cumulative value for an overall lifetime cancer risk ranging from 5.70 × 10 − 4 to 4.10 × 10− 3 with a mean value of 1.09 × 10− 3. Solubility-free ion activity model (FIAM) could explain up to 75% variation in As concentration in rice grain. This model has been successfully validated in half of the data set for its future use for the first time. A ready reckoner was developed based on FIAM to define toxic limits of extractable As in soil with reference to pH, OC, and grain As content.

Hydrogen has been championed as a vital player in the future energy mix needed to achieve net-zero carbon emissions. The deployment of hydrogen at an industrial scale will require pipelines for transportation, and given the many obstacles to new pipeline construction, it appears inevitable that a large proportion of the future hydrogen pipeline network will consist of repurposed existing infrastructure. Conversion strategies require that retrofit pipelines remain operationally safe under the new mode of transportation. From an integrity perspective, the conversion exercise will require understanding the line pipe material’s “DNA” (e.g. grades, hard spots) and assessing the impact of hydrogen on key pipeline mechanical properties (e.g. fracture toughness) and on the tolerance of integrity threats. These threats include those that may already exist from previous hydrocarbon service (e.g. stress-corrosion cracking), those that are directly related to the conversion to hydrogen (e.g. fatigue) and those that are an integral part of a pipeline life cycle (e.g. third-party damages, geohazards). There is currently a lack of clarity within the industry about how to quantify and manage these threats to hydrogen pipelines. How, if at all, should an integrity management strategy for a hydrogen pipeline differ from that of a natural gas pipeline? In order to define the boundaries of the existing North American pipeline network and the starting point for conversion, this paper will conduct an Exploratory Data Analysis (EDA) of (i) the pipeline network’s “DNA” (e.g. diameters, thicknesses, grades, fracture toughness, hard spots, age), and (ii) the pipeline threat and condition attributes (e.g. pre-existing crack threats, crack distribution). This paper will take advantage of the knowledge derived from the ROSEN Integrity Data Warehouse (IDW), a global repository of ILI results and Integrity Management, in order to quantify the characteristics specific to North America. A pragmatic approach to safely repurposing existing pipelines to hydrogen service will be then presented in recognition of the identified regional ‘DNA’ and integrity peculiarities, and in respect to applicable local codes and regulations.

Recent incidents outside Canada prompted the Canadian Energy Regulator (CER), the British Columbia Oil & Gas Commission (BCOGC) and the Alberta Energy Regulator (AER) to advise pipeline operators regarding the possibility of girth weld strain-induced failures in high strength pipe. In early 2020, the CER issued a Safety Advisory (SA) relating to the possibility of girth weld strain-induced failures in high strength (Grade X 70 or higher) steel line pipe. There was a concern that similar incidents could occur in Canada, given comparable conditions. Furthermore, the SA stated that.... “The CER expects that regulated companies can demonstrate that longitudinal strains resulting from loadings such as those described in Section 4.2.4 of CSA Z662-19 [essentially external loading over and above typical operating loads] have been accounted for in the design, construction and operation of pipelines where strain could potentially accumulate in under-matched girth welds”. With respect to the SA, the failure causes were consistently linked to combinations of: i) high strength pipe with a minimum tensile strength exceeding actual weld strength values, ii) girth weld HAZ softening as a result of the welding process, iii) loads applied to the pipeline causing additional longitudinal strain, and iv) pipes welded with a standard bevel and alignment of approximately 45° between the heat affected zone (HAZ) and the root bead. Emera New Brunswick (Emera) initiated an assessment of the 30 inch diameter, 145 km long, API 5L Grade X70 Brunswick Pipeline that evaluated: i) pipeline material, welding and construction records with respect to specified requirements, and ii) the propensity of the pipeline to external loading via the analysis of repeat inertial measurement unit (IMU) data and a geohazard review of locations exhibiting bending strain to understand the stability of the pipeline in relation to potential external loading. This paper describes the systematic approach taken to address the potential concerns, the key results and recommendations of the study and how Emera has incorporated those findings into processes within its management system and protection programs.

Over the coming decade many projects will be initiated to convert existing natural gas pipelines to hydrogen service, often with ambitious schedules. However, there is currently little experience globally in successfully converting pipelines to hydrogen service and operating them safely. In North America, the gas transmission infrastructure represents construction from the 1920s up to the present day. This infrastructure contains a wide spectrum of different pipeline materials with large variations in properties, and an array of different resident and time-dependent integrity threats. Prior to embarking on changes to hydrogen service, it is imperative to understand and mitigate the effects associated with the change in risk profile, driven by the known effects of hydrogen gas on the toughness and fatigue resistance of steel pipelines. These effects are complicated by the significant variation and uncertainty in the extent to which different pipeline materials will be affected. Many papers and industry projects have examined the effects of hydrogen on material properties. However, few have assessed the scale of the challenge posed to safe operation and integrity management involved with repurposing an entire infrastructure. This paper uses a novel approach to explore how the current natural gas transmission network might stand up to a hypothetical switch to 100% hydrogen. Available data gathered through inspections of gas transmission pipelines in North America will be utilised to create a virtual pipeline network. This virtual system is built from a range of different pipeline sizes, attributes and material properties to most closely represent a ‘typical’ proportion of the gas transmission network in North America. An array of cracks and crack-like integrity threats with sizes and morphologies that reflect typical frequencies and severities observed from real projects will be introduced into this virtual network. This virtual network is a construct that allows the impact of hydrogen conversion on integrity management to be explored in a way that is representative of what a gas transmission pipeline operator may expect to encounter across a range of assets. The impacts will be explored through different scenarios, representing different extents of reductions in toughness and increases in fatigue crack growth rates, based on available material test data. This approach will provide an indication of the number of features that may be currently stable in natural gas but that may fail in hydrogen service. This hypothetical exercise will draw insights into the practicalities of safe operation of pipelines being contemplated for hydrogen service and the scale of the task that would be necessary to navigate this transition.

Delayed sowing of maize hybrids could exacerbate the capability of maximizing the yield potential through poor crop stand, root proliferation, nutrient uptake, and dry matter accumulation coupled with the inadequate partitioning of the assimilates. This study appraised the performance of five recent maize hybrids viz., PMH-1, PJHM-1, AH-4158, AH-4271, and AH-8181 under timely and late sown conditions of the irrigated semi-arid ecologies. Timely sowing had the grain and stover yields advantage of 16-19% and 12-25%, respectively over the late sown maize hybrids. The advanced hybrids AH-4271 and AH-4158 had higher grain yields than the others. During the post-anthesis period, a greater dry matter accumulation and contribution to the grain yield to 16% and 10.2%, respectively, was observed under timely sown conditions. The nutrient acquisition and use efficiencies also improved under the timely sown. The nutrient and dry matter remobilization varied among the hybrids with AH-4271 and PMH-1 registering the greater values. The grain yield stability index (0.85) was highest with AH-4158 apart from the least yield reduction (15.2%) and stress susceptibility index (0.81), while the maximum geometric mean productivity was recorded with the AH-4271 (5.46 Mg ha–1). The hybrids AH-4271 and PJHM-1 exhibited improved root morphological traits, such as root length, biomass, root length density, root volume at the V5 stage (20 days of sowing, DAS) and 50% flowering (53 DAS). Thus, timely sowing and appropriate hybrids based on stress tolerance indices resulted in greater yields and better utilization of resources.

Owing to the similar chemistry of phosphorus (P) and arsenic (As), sodium bicarbonate (0.5 N NaHCO3) is commonly used to extract plant accessible As in soil. However, 0.5 N NaHCO3 is not compatible with the ICP-MS measurement due to the large amount of dissolved solids. This investigation set out to devise a suitable extractant for determining extractable As in soil and measured by the ICP-MS. Paired soil and plant samples were collected from paddy fields in West Bengal, India. Soil was extracted with 0.5 M NaHCO3, 0.03 M (0.1 N) and 0.17 M (0.5 N) phosphoric acid (H3PO4), 0.05 M (0.1 N) and 0.25 M (0.5 N) sulfuric acid (H2SO4), and 0.01 M calcium chloride (CaCl2). This made it possible to measure As by hydride generation-atomic absorption spectrophotometer (HG-AAS), while ICP-MS was used for the determination of As extracted from soil with different concentrations (0.1-1.5M) of HNO3. The NaHCO3 extractable As was 1.45 and 1.23 mg kg− 1 for soil to extractant ratio of 1:20 and 1:5, respectively. Of these extractants, 1.5 N HNO3 extractable As had the best correlation with As content in rice grain (r = 0.45**) and straw (r = 0.71**), comparable with standard extractant i.e. 0.5 N NaHCO3 (r = 0.47** and r = 0.64** in case of grain and straw, respectively). A significant positive relationship of 1.5 N HNO3 was obtained with 0.5 N NaHCO3. Thus, 1.5 N HNO3 may serve as an extractant for soil As, which is compatible with ICP-MS analysis.

There is a growing realization that the complexity of model ensemble studies depends not only on the models used but also on the experience and approach used by modelers to calibrate and validate results, which remain a source of uncertainty. Here, we applied a multi-criteria decision-making method to investigate the rationale applied by modelers in a model ensemble study where 12 process-based different biogeochemical model types were compared across five successive calibration stages. The modelers shared a common level of agreement about the importance of the variables used to initialize their models for calibration. However, we found inconsistency among modelers when judging the importance of input variables across different calibration stages. The level of subjective weighting attributed by modelers to calibration data decreased sequentially as the extent and number of variables provided increased. In this context, the perceived importance attributed to variables such as the fertilization rate, irrigation regime, soil texture, pH, and initial levels of soil organic carbon and nitrogen stocks was statistically different when classified according to model types. The importance attributed to input variables such as experimental duration, gross primary production, and net ecosystem exchange varied significantly according to the length of the modeler’s experience. We argue that the gradual access to input data across the five calibration stages negatively influenced the consistency of the interpretations made by the modelers, with cognitive bias in “trial-and-error” calibration routines. Our study highlights that overlooking human and social attributes is critical in the outcomes of modeling and model intercomparison studies. While complexity of the processes captured in the model algorithms and parameterization is important, we contend that (1) the modeler’s assumptions on the extent to which parameters should be altered and (2) modeler perceptions of the importance of model parameters are just as critical in obtaining a quality model calibration as numerical or analytical details. info:eu-repo/semantics/acceptedVersion

A study was undertaken to evaluate the long term effect of different conservation agriculture (CA) practices on infiltration characteristics of soil and empirical Kostiakov model and physical process based Green and Ampt, and Philip models were used to predict infiltration rates. The performance of different models was evaluated using statistical criteria. Six treatments were selected, viz. conventional tillage (CT), permanent narrow bed (PNB), permanent narrow bed with residue (PNB+R), permanent broad bed (PBB), permanent broad bed with residue (PBB+R) and zero tillage (ZT). Results showed that the initial infiltration rate was highest (22.93 cm hr-1) in PBB+R and was lowest (7.64 cm hr-1) in CT. Cumulative infiltration of all the treatments followed the order: PBB+R>PNB+R>PBB>PNB>ZT>CT. The ‘a’ values of Kostiakov model was 197.5 and 310 % higher in PBB and PBB+R as compared to CT. Steady state infiltration (ic) of Green and Ampt model was found to be highest (8.47 cm hr-1) in PBB+R and was lowest (1.88 cm hr-1) in CT. Sorptivity (S) parameter (cm hr-0.5) of the Phillip model was found to be highest in PNB+R (67.33) followed by PBB+R (43.61) and lowest in CT (16.23). Highest saturated hydraulic conductivity (‘K’) value of Phillip model was obtained in PBB+R followed by PBB> PNB>PNB+R>CT. After checking the model performance, it has been found that simple empirical Kostiakov (1932) infiltration model represented the infiltration rate and time relationship in a better way and characterized the best fit with the experimentally observed field infiltration data.

Contrasting tillage and land configuration have important roles in porosity and pore size distribution (PSD), which in turn affects the carbon mineralization in soil. Information on the effects of these treatments on PSD and subsequent carbon mineralization is very limited. Hence, an attempt was made to evaluate the long-term impact of soil tillage and land configurations on the distribution of soil pores and its relationship with soil carbon mineralization under a maize (Zea mays)-wheat (Triticum aestivum) rotation. There were five treatments, that is, conventional tillage, (CT); permanent broad bed, (PBB); PBB + residue (R); zero tillage, (ZT); and ZT + R. Soil pores were quantified by X-ray computed tomography (μ-CT). The conversion of CT to ZT and PBB with or without residue retention (+R) resulted in the reduction of pores >60 μm diameter and was mostly due to a reduction in the number of larger size macro-pores (>110 μm). This resulted in restricted drainage. However, under these practices, pores with larger diameters (60–110 μm) facilitated soil aeration. The total organic carbon (TOC) was 15–48% and 17–47% higher under PBB, PBB + R, ZT, and ZT + R than that under CT in the 0–5 and 5–15 cm layers. The highest MWD (1.01 mm) was in the plots under PBB + R, and the lowest was in the CT plots, and all residue-retained plots (ZT + R and PBB + R) had a higher MWD than residue removal plots (ZT and PBB). Relative to CT, soil C mineralization rates in 0–5 and 5–15 cm soil depths were 63 and 55% higher in the alternate tillage practices, respectively, and the highest value occurred in PPB + R treatments. Increased labile C concentrations were indicative of greater mineralization and were correlated with pores >60 μm, particularly in the size range 110–500 μm and TOC concentrations of 0–15 cm soil layer. Thus, the transition to alternate tillage from the conventional tillage enhanced soil organic carbon concentration (16–47.5%), improved soil structure, reduced the diameter of pores up to >60 μm, and facilitated C mineralization by altering the pore size distribution of soil under a maize-wheat system in the IGP.

For sustainable crop production and maintenance of soil health, conservation agriculture (CA) practices provides an opportunity for improving soil structure and physical health, nutrient and water use efficiency, soil organic carbon and mitigation of greenhouse gases emission from agriculture. CA is primarily based on four crop management practices such as minimum soil disturbance or no-tillage; permanent or semi-permanent retention of crop residue; crop rotation and control traffic. Different CA management practices affect crop yield as well as soil properties. CA makes necessary modifications in different soil hydro-physical properties, viz. increase in soil water infiltration, reduction in water runoff and soil loss, and reduction in evaporation loss. No tillage (NT), residue retention and crop rotation combined effect the soil organic carbon concentration. Different crop rotations and residue retentions and crops with different rooting depths used in CA practices have proved to reduce the compaction constraints.CA can help to mitigate GHG emissions, viz methane (CH4) and nitrous oxide (N2O) from agriculture by improving soil C sequestration, enhancing soil quality, nitrogen and water use efficiencies, and decreasing fuel consumption. But effect of CA and conventional agricultural practices of porosity and pore size distribution is very much limited. When CA is practiced for six to ten years there is improvement in soil structure, porosity and pore size distribution, macro-micro faunal activity, and organic matter content..The soil under ZT has the lowest porosity as compared to conventional management practices. The highest porosity and the maximum connected pores are frequently seen in conventionally tilled soil. In this paper, an attempt has been made to review the variation of porosity and pore size distribution and other soil physical properties under conservation agricultural practices.

Tropospheric ozone stress adversely affects crop cultivars growth and productivity variably. The variable response of crop cultivars raised the need for identification of ozone (O3) stress-tolerant cultivars as an adaptive option. In the present study, forty cultivars of Amaranthus hypochondriacus were screened for susceptibility and tolerance to ozone stress. The cultivars were exposed to ambient (AO3) and elevated (EO3) ozone levels in free air ozone enrichment (FAOE) facility and monitored for foliar ozone injury symptoms appearance and yield attributes response. Foliar ozone injury symptoms on Amaranthus cultivars were interveinal yellow or black spots. Foliar ozone injury was observed in almost half of the cultivars and the maximum foliar injury (> 75%) was observed in cultivar IC-5527. The maximum yield reduction (> 90%) was observed in cultivars IC-4200 (94.9%) and IC-5569 (91.4%) compared to other cultivars. The results showed that Amaranthus cultivars exhibited variable response towards ozone stress where foliar ozone injury does not always correspond with grain yield reductions. Among the indices, Relative Yield Index (RYI), Stress tolerance (TOL), Abiotic Tolerance Index (ATI), Susceptibility Index (S) and Stress Susceptibility Index (SSSI) were positively correlated with relative yield loss in all the cultivars under ozone stress. With the help of cluster analysis and principal component analysis (PCA), the cultivars were categorized into ozone tolerant, moderately ozone tolerant and ozone susceptible category. The most tolerant cultivars were IC-5527 and IC-1733 which exhibited lower yield losses whereas the most susceptible cultivars were IC-3599 and IC-7924 having high foliar injury and maximum yield losses as compared to other cultivars. The most ozone tolerant cultivars of Amaranthus identified in this study may be recommended for cultivation to farmers in the areas experiencing EO3 during the Amaranthus crop growth period.

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only inc...

Global warming impacts of N use in Indian agriculture since 1960 was estimated for 20- and 100-year time scales using equation-based empirical method. During 2014, total Warming in terms of global ...

An experiment was conducted by growing Pusa 44 rice (Oryza sativa L.) variety under different treatments: Ambient, Elevated O3 (EO3: 60 ± 10 ppb), Elevated CO2 (ECO2: 550 ± 10 ppm) and Elevated CO2 and O3 (550 ± 10 ppm CO2 and 60 ± 10 ppb EO3) in free air carbon dioxide and ozone enrichment facility (FACE-O3) with the objective to assess the impact of elevated tropospheric ozone (O3) and carbon dioxide (CO2) interaction on growth and yield of rice. The crop was exposed to elevated levels of gases from transplanting to maturity. EO3 was found to be having a negative impact on all the growth parameters at vegetative, anthesis and maturity stages. ECO2 was found to be having a compensatory effect over EO3 for the different growth parameters. On an average the compensatory effect of ECO2 over EO3 on yield was about 40% and negative impact of elevated O3 over control was around 26% in both the years.

Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ...

Reports on the adverse impacts of climate change on growth and productivity of crops due to elevated temperature and carbon dioxide concentration ([CO2]) is persistently raising the need for development of tools to assess response of crops to climate change factors. In the present study, Crop Health Index (CHI) was generated for response of maize genotypes under elevated temperature and [CO2]. Under field condition, in open top chambers PEHM 5 and CM 119 maize genotypes throughout their crop growth period were treated with two [CO2] levels: ambient (400 ppm) and elevated (550 ± 20 ppm) and three temperature levels: ambient, ambient +1.5 °C and ambient +3 °C. Response of maize genotypes to temperature and [CO2] was monitored through thirteen stress indicator parameters – morphological, physiological and biochemical at three growth stages – vegetative, tasselling and dent. Yield for both genotypes under each treatment was recorded at maturity. The data was used to delineate minimum dataset (MDS) responsive to combinations of temperature and [CO2] treatments through principal component analysis (PCA). Out of thirteen indicators, total dry biomass, total phenol content, relative leaf water content and photosynthetic rate was found to be having higher frequencies for MDS at all three stages. Parameters selected under MDS were transformed to get linear score (Si) using a linear scoring method and weighing factor (Wf) value. Then, average linear score ( S i ¯ ) [(Si)] and average weightage score ( W i ¯ ) were used to generate CHI. Results indicated that CHI for maize genotypes under different treatments varied between 0.14–0.93. Average CHI under different treatment was significantly related with yield of PEHM 5 and CM 119 and R2 was 0.82 and 0.90, respectively. It was observed that increase in temperature had detrimental effect on CM 119 and PEHM 5 genotypes with minimum average CHI of 0.20 and 0.53, respectively. On the contrary, elevated [CO2] was found to be having amelioration effect on CM 119 and PEHM 5 genotypes to adverse effect of elevated temperature with highest average CHI of 0.46 and 0.75, respectively.

Due to its lower water requirement, methane emission and soil degradation, a maize–wheat rotation (MWR) may be a more attractive alternative to rice–wheat rotation (RWR), in the upper Indo-Gangetic...

Increase in the atmospheric carbon dioxide (CO2) concentration has fertilization effect on crops if nutrient supply remains adequate. Response of cereals and legumes to increased CO2 concentration might differ due to the nitrogen fixing ability of leguminous crops. Considering the importance of differential response of cereal and legumes under elevated CO2 concentration, a field study was conducted to compare the effect of elevated CO2 on yield and plant nitrogen uptake in wheat and chickpea crop. Elevated CO2 level (550 ppm) increased yield by 15.1% and 16.7% over ambient in wheat and by 21.1% and 21.9% in chickpea (p ≤ 0.05) during the first and second years of the study. Nitrogen content in wheat grains decreased under elevated CO2 concentration. Chickpea, being a leguminous crop, showed no change in grain N content. However, higher biomass and grain yield resulted in higher N uptake in both the crops under elevated CO2 level. Under elevated CO2 concentration more partitioning of biomass toward seeds lead to higher seed N partitioning in chickpea. The study showed that although growth and yield of crops might increase in high CO2 condition, nitrogen concentration in grains and soil available N status might decrease in cereals like wheat. But chickpea might not get affected due to their ability to fix atmospheric N2.

The sustainability of conventional rice (Oryza sativa L.) production systems is often questioned due to the over-mining of groundwater and environmental degradation. This has led to the development of cost-effective, resource-efficient, and environmentally clean rice production systems by optimizing water and nitrogen (N) use. Hence, a 2-year field study (2019 and 2020) was conducted at the ICAR–Indian Agricultural Research Institute, New Delhi, to assess the effect of precision N and water management strategies on growth, land, and water productivity, as well as energy-use efficiency in scented direct-seeded rice (DSR). Two crop establishment methods, conventional-till DSR (CT-DSR) and zero-till DSR (ZT-DSR) along with three irrigation scenarios (assured irrigation (irrigation after 72 h of the drying of surface water), irrigation at 20% depletion of available soil moisture (DASM), and 40% DASM+Si (80 kg ha−1)) were assigned to the main plots; three N management options, a 100% recommended dose of N (RDN): 150 kg ha−1; Nutrient Expert® (NE®)+leaf color chart (LCC) and NE®+soil plant analysis development (SPAD) meter-based N management were allocated to sub-plots in a three-time replicated split-plot design. The CT-DSR produced 1.4, 11.8, and 89.4, and 2.4, 18.8, and 152.8% more grain yields, net returns, and net energy in 2019 and 2020, respectively, over ZT-DSR. However, ZT-DSR recorded 8.3 and 10.7% higher water productivity (WP) than CT-DSR. Assured irrigation resulted in 10.6, 16.1 16.9, and 8.1 and 12.3, 21.8 20.6, and 6.7% higher grain yields, net returns, net energy, and WP in 2019 and 2020, respectively, over irrigation at 20% DASM. Further, NE®+SPAD meter-based N management saved 27.1% N and recorded 9.6, 18.3, 16.8, and 8.3, and 8.8, 21.7, 19.9, and 10.7% greater grain yields, net returns, net energy, and WP over RDN in 2019 and 2020, respectively. Thus, the study suggested that the NE®+SPAD-based N application is beneficial over RDN for productivity, resource-use efficiency, and N-saving (~32 kg ha−1) both in CA-based and conventionally cultivated DSR. This study also suggests irrigating DSR after 72 h of the drying of surface water; however, under obviously limited water supplies, irrigation can be delayed until 20% DASM, thus saving two irrigations, which can be diverted to additional DSR areas.

The experiment was conducted during 2018-19 and 2019-20 at ICAR-IARI research farm, to see the effect of crop establishment and nutrient management options on growth and yield of wheat under maize-wheat system. The experiment was laid out in split plot design with 03 replications, comprising conventional tillage without residue (CT-R), conventional tillage with 3 t/ha residue (CT+R), permanent raised bed without residue (PRB-R) and permanent raised bed with 3 t/ha residue (PRB+R) in main plot and nutrient management, viz. soil test-based(STB), Nutrient Expert® based (NE) and NE+ GreenSeekerTM based recommendations (NE+GS) in sub-plot. A significantly (P≤0.05) higher crop growth, viz. plant height, dry matter accumulation and leaf area index under PRB+R compared to other crop establishment technique. Differentyield parameters (yield, grain straw ratio and harvest index) and yield attributes of wheat grown under PRB+R were significantly higher (P≤0.05) over other crop establishment technique. A significantly (P≤0.05) higher crop growth, yield attributes, grain yield (5.01 and 5.05 t/ha), grain: straw ratio (0.65 and 0.65) and harvest index (39.31 and 39.36) of wheat were recorded with NE+GS based fertilization during 2018-19 and 2019- 20, respectively. Pearson correlation matrix analyzed for different growth and yield parameters showed a significant positive correlation (r) among themselves. Study infer that growing of wheat on the permanent raised bed along with 03 t/ha residue retention on surface and precision nutrient prescription using NE and GreenSeekerTM optical sensor showed promise for sustainable high productivity in intensively cultivated Trans-Gangetic Plains.

Methane utilizing bacteria (MUB) are known to inhabit the flooded paddy ecosystem where they play an important role in regulating net methane (CH4) emission. We hypothesize that efficient MUB having plant growth-promoting (PGP) attributes can be used for developing novel bio-inoculant for flooded paddy ecosystem which might not only reduce methane emission but also assist in improving the plant growth parameters. Hence, soil and plant samples were collected from the phyllosphere, rhizosphere, and non-rhizosphere of five rice-growing regions of India at the tillering stage and investigated for efficient methane-oxidizing and PGP bacteria. Based on the monooxygenase activity and percent methane utilization on NMS medium with methane as the sole C source, 123 isolates were identified and grouped phylogenetically into 13 bacteria and 2 yeast genera. Among different regions, a significantly higher number of isolates were obtained from lowland flooded paddy ecosystems of Aduthurai (33.33%) followed by Ernakulum (20.33%) and Brahmaputra valley (19.51%) as compared to upland irrigated regions of Gaya (17.07%) and Varanasi (8.94%). Among sub-samples, a significantly higher number of isolates were found inhabiting the phyllosphere (58.54%) followed by non-rhizosphere (25.20%) and rhizosphere (15.45%). Significantly higher utilization of methane and PGP attributes were observed in 30 isolates belonging to genera Hyphomicrobium, Burkholderia, Methylobacterium, Paenibacillus, Pseudomonas, Rahnella, and Meyerozyma. M. oryzae MNL7 showed significantly better growth with 74.33% of CH4 utilization at the rate of 302.9 ± 5.58 and exhibited half-maximal growth rate, Ks of 1.92 ± 0.092 mg CH4 L−1. Besides the ability to utilize CH4, P. polymyxa MaAL70 possessed PGP attributes such as solubilization of P, K, and Zn, fixation of atmospheric N and production of indole acetic acid (IAA). Both these promising isolates can be explored in the future for developing novel biofertilizers for flooded paddies.

In the last six decades, the consumption of reactive nitrogen (Nr) in the form of fertilizer in India has been growing rapidly, whilst the nitrogen use efficiency (NUE) of cropping systems has been decreasing. These trends have led to increasing environmental losses of Nr, threatening the quality of air, soils, and fresh waters, and thereby endangering climate-stability, ecosystems, and human-health. Since it has been suggested that the fertilizer consumption of India may double by 2050, there is an urgent need for scientific research to support better nitrogen management in Indian agriculture. In order to share knowledge and to develop a joint vision, experts from the UK and India came together for a conference and workshop on “Challenges and Opportunities for Agricultural Nitrogen Science in India.” The meeting concluded with three core messages: (1) Soil stewardship is essential and legumes need to be planted in rotation with cereals to increase nitrogen fixation in areas of limited Nr availability. Synthetic symbioses and plastidic nitrogen fixation are possibly disruptive technologies, but their potential and implications must be considered. (2) Genetic diversity of crops and new technologies need to be shared and exploited to reduce N losses and support productive, sustainable agriculture livelihoods. (3) The use of leaf color sensing shows great potential to reduce nitrogen fertilizer use (by 10–15%). This, together with the usage of urease inhibitors in neem-coated urea, and better management of manure, urine, and crop residues, could result in a 20–25% improvement in NUE of India by 2030.

A total of six vegetables (S. tuberosum, D. carota, S. lycopersicum, A. esculentus, S. oleracea and B. juncea) were analysed for five heavy metals (As, Cd, Cr, Hg, and Pb) to evaluate the contamination load in vegetables collected from five cultivated and two market sites (n = 504) at Delhi, India. The irrigation water samples and soil samples (n = 180) were only collected from cultivated sites. The results showed that the concentration of heavy metals in soil and water samples were well below the permissible level except for Cd 0.001-0.013 µg g

In the present study wheat (Triticum aestivum) cultivar HD 2967 was exposed to ambient and elevated levels of O

An experiment was conducted in the Free Air Ozone and Carbon dioxide Enrichment (FAOCE) facility to study the impact of elevated O3, CO2 and their interaction on chickpea crop (cv. Pusa-5023) in terms of phenology, biophysical parameters, yield components, radiation interception and use efficiency. The crop was exposed to elevated O3 (EO:60ppb), CO2 (EC:550 ppm) and their combined interactive treatment (ECO: EC+EO) during the entire growing season. Results revealed that the crop’s total growth period was shortened by 10, 14 and 17 days under elevated CO2, elevated O3 and the combined treatment, respectively. Compared to ambient condition, the leaf area index (LAI) under elevated CO2 was higher by 4 to 28%, whilst it is reduced by 7.3 to 23.8% under elevated O3. The yield based radiation use efficiency (RUEy) was highest under elevated CO2 (0.48 g MJ−1), followed by combined (0.41 g MJ−1), ambient (0.38 g MJ−1) and elevated O3 (0.32 g MJ−1) treatments. Elevated O3 decreased RUEy by 15.78% over ambient, and the interaction results in a 7.8% higher RUEy. The yield was 31.7% more under elevated CO2 and 21.9% lower in elevated O3 treatment as compared to the ambient. The combined interactive treatment recorded a higher yield as compared to ambient by 9.7%. Harvest index (HI) was lowest under elevated O3 (36.10%), followed by ambient (39.18%), combined (40.81%), and highest was under elevated CO2 (44.18%). Chickpea showed a positive response to elevated CO2 resulting a 5% increase in HI as compared to ambient condition. Our findings quantified the positive and negative impacts of elevated O3, CO2 and their interaction on chickpea and revealed that the negative impacts of elevated O3 can be compensated by elevated CO2 in chickpea. This work promotes the understanding of crop behaviour under elevated O3, CO2 and their interaction, which can be used as valuable inputs for radiation-based crop simulation models to simulate climate change impact on chickpea crop.

Priming is used to increase vigor, germination synchronization, seedling growth, and field establishment by advancing metabolic processes within seeds. Seed respiration is a good indicator of the metabolic processes that lead to transition toward germination. Onion seeds (cv. Pusa Ridhi) subjected to osmopriming (−1.5 MPa PEG6000 for 7 days), magnetopriming (100 mT for 30 min) and halopriming (150 mM KNO3 for 6 days), were evaluated at different times of imbibition to study the emergence index and respiration indices such as infrared thermal fingerprint, CO2 evolution rate, cytochrome c oxidase activity, and soluble sugars profile. Haloprimed seeds exhibited 42.5% higher emergence index as compared to unprimed control. Primed and unprimed seeds showed negative values for relative temperature (ΔT) (difference in temperature of seed and its immediate environment). Haloprimed seeds had the lowest values (−4.1 to −2.3°C) compared to other priming treatments over the germination period. Soluble sugars like raffinose, sucrose, glucose, and fructose contents were monitored and it was observed that en masse raffinose, glucose, and fructose levels were (17.5–59.9%) lower in haloprimed seeds over control. A positive correlation (r2 = 0.504∗∗) was derived between the amount of these sugars and ΔT. Seed respiration, measured as CO2 evolution rate was more for haloprimed seeds that indicated that these soluble sugars were used as respiratory substrates. Significantly higher cytochrome c oxidase activity (40.7–89.8% and 12.5–66.6%) was observed in all primed seeds at 28 and 36 h, respectively. Among the various seed priming methods, halopriming proved to be the most effective priming treatment in onion seeds as evidenced by the higher respiration indices that resulted in faster metabolic rate and emergence index.

Methane utilizing bacteria (MUB) are known to inhabit the flooded paddy ecosystem where they play an important role in regulating net methane (CH

Irrigated transplanted flooded rice is a major source of methane (CH4) emission. We carried out experiments for 2 years in irrigated flooded rice to study if interventions like methane-utilizing bacteria, Blue-green algae (BGA), and Azolla could mitigate the emission of CH4 and nitrous oxide (N2O) and lower the yield-scaled global warming potential (GWP). The experiment included nine treatments: T1 (120 kg N ha−1 urea), T2 (90 kg N ha−1 urea + 30 kg N ha−1 fresh Azolla), T3 (90 kg N ha−1 urea + 30 kg N ha−1 Blue-green algae (BGA), T4 (60 kg N ha−1 urea + 30 kg N ha−1 BGA + 30 kg N ha−1 Azolla, T5 (120 kg N ha−1 urea + Hyphomicrobium facile MaAL69), T6 (120 kg N ha−1 by urea + Burkholderia vietnamiensis AAAr40), T7 (120 kg N ha−1 by urea + Methylobacteruim oryzae MNL7), T8 (120 kg N ha−1 urea + combination of Burkholderia AAAr40, Hyphomicrobium facile MaAL69, Methylobacteruim oryzae MNL7), and T9 (no N fertilizer). Maximum decrease in cumulative CH4 emission was observed with the application of Methylobacteruim oryzae MNL7 in T7 (19.9%), followed by Azolla + BGA in T4 (13.2%) as compared to T1 control. N2O emissions were not significantly affected by the application of CH4-oxidizing bacteria. However, significantly lower (P

Croplands and grasslands are agricultural systems that contribute to land–atmosphere exchanges of carbon (C). We evaluated and compared gross primary production (GPP), ecosystem respiration (RECO), net ecosystem exchange (NEE) of CO2, and two derived outputs - C use efficiency (CUE=-NEE/GPP) and C emission intensity (IntC= -NEE/Offtake [grazed or harvested biomass]). The outputs came from 23 models (11 crop-specific, eight grassland-specific, and four models covering both systems) at three cropping sites over several rotations with spring and winter cereals, soybean and rapeseed in Canada, France and India, and two temperate permanent grasslands in France and the United Kingdom. The models were run independently over multi-year simulation periods in five stages (S), either blind with no calibration and initialization data (S1), using historical management and climate for initialization (S2), calibrated against plant data (S3), plant and soil data together (S4), or with the addition of C and N fluxes (S5). Here, we provide a framework to address methodological uncertainties and contextualize results. Most of the models overestimated or underestimated the C fluxes observed during the growing seasons (or the whole years for grasslands), with substantial differences between models. For each simulated variable, changes in the multi-model median (MMM) from S1 to S5 was used as a descriptor of the ensemble performance. Overall, the greatest improvements (MMM approaching the mean of observations) were achieved at S3 or higher calibration stages. For instance, grassland GPP MMM was equal to 1632 g C m−2 yr-1 (S5) while the observed mean was equal to 1763 m-2 yr-1 (average for two sites). Nash-Sutcliffe modelling efficiency coefficients indicated that MMM outperformed individual models in 92.3 % of cases. Our study suggests a cautious use of large-scale, multi-model ensembles to estimate C fluxes in agricultural sites if some site-specific plant and soil observations are available for model calibration. The further development of crop/grassland ensemble modelling will hinge upon the interpretation of results in light of the way models represent the processes underlying C fluxes in complex agricultural systems (grassland and crop rotations including fallow periods). info:eu-repo/semantics/acceptedVersion

Wilt caused by Fusarium oxysporum, sp. Ciceris (FOC) is an important disease causing losses up to 10% in chickpea yield. Experiments were conducted growing chickpea in free air ozone and carbon dioxide enrichment rings under four treatments of elevated ozone (O3) (EO:60 ± 10 ppb), elevated carbon dioxide (CO2) (ECO2:550 ± 25 ppm), combination of elevated CO2 and O3 (EO + ECO2) and ambient control for quantifying the effect on growth, yield, biochemical and nutrient content of chickpea. For studying the impact on wilt disease, chickpea was grown additionally in pots with soil containing FOC in these rings. The incidence of Fusarium wilt reduced significantly (p < 0.01) under EO as compared to ambient and ECO2. The activities of pathogenesis-related proteins chitinase and β-1,3- glucanase, involved in plant defense mechanism were enhanced under EO. The aboveground biomass and pod weight declined by 18.7 and 15.8% respectively in uninnoculated soils under EO, whereas, in FOC inoculated soil (diseased plants), the decline under EO was much less at 8.6 and 9.9% as compared to the ambient. Under EO, the activity of super oxide dismutase increased significantly (p < 0.5, 40%) as compared to catalase (12.5%) and peroxidase (17.5%) without any significant increase under EO + ECO2. The proline accumulation was significantly (p < 0.01) higher in EO as compared to EO + ECO2, and ECO2. The seed yield declined under EO due to significant reduction (p < 0.01) in the number of unproductive pods and seed weight. No change in the protein, total soluble sugars, calcium and phosphorus content was observed in any of the treatments, however, a significant decrease in potassium (K) content was observed under EO + ECO2. Elevated CO2 (554ppm) countered the impacts of 21.1 and 14.4 ppm h (AOT 40) O3 exposure on the seed yield and nutrient content (except K) in the EO + CO2 treatment and reduced the severity of wilt disease in the two years' study., Wilt; Elevated ozone; Elevated carbon dioxide; Chickpea; Fusarium oxysporium