Response of maize and its pest Chilo partellus to ozone and carbon dioxide exposure

In the present study, the direct effect of ozone (O3) and carbon dioxide (CO2) exposure on growth and yield of maize (var HQPM 1) and the indirect effect on development of its herbivore pest Chilo partellus were investigated. Maize crop was exposed to different concentrations of O3 and CO2 in open top chambers (OTCs). During the exposure, maize plants at the early vegetative stage were incubated with C. partellus eggs. Changes in biomass and yield of maize plants with and without Chilo infestation under O3 and CO2 exposure were monitored. Indirect effects of O3 and CO2 on maize pest were monitored with respect to release and survival of larvae, mean body weight of ἀfth instar stage larvae and emergence of adults from pupae. Higher reductions in aboveground and belowground biomass were observed in maize plants with pest with respect to plants without pest during O3 and CO2 exposure. Maximum and minimum reductions in aboveground (39.5% and 4.7%) and belowground biomass (43.0% and 5.4%) were observed in maize plants grown under O3 and CO2 treatments, respectively. Reduction in yield varied from 33.8% to 15.2% for maize plants grown under different treatments as compared to plants grown under low O3 conditions. Signiἀcant changes in development of C. partellus, fed on tissues of maize plants exposed to different treatments were observed. Moreover, the mean body weight of larvae decreased with increasing O3 concentrations. Mean body weight was 62% higher and 65% lower for larvae fed on maize plant tissue exposed to CO2 and CO2+EO3, respectively, as compared to maize plants grown under low O3 conditions. Development of male and female adults from pupae was observed only from larvae isolated from ambient and CO2 treated maize plants. The present study showed that the exposure of maize crop to O3 and CO2 and its pest C. partellus, adversely affected not only maize growth and yield but also development of C. partellus. This study suggests that predicting the outcome of O3 and CO2 on crop-insect pest interactions will require comprehensive examination of behavioural growth of both harmful and beneἀcial insects of the agro-ecosystem

Leveraging population admixture to characterize the heritability of complex traits.

Despite recent progress on estimating the heritability explained by genotyped SNPs (h(2)g), a large gap between h(2)g and estimates of total narrow-sense heritability (h(2)) remains. Explanations for this gap include rare variants or upward bias in family-based estimates of h(2) due to shared environment or epistasis. We estimate h(2) from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (h(2)γ). We show that h(2)γ = 2FSTCθ(1 - θ)h(2), where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion. Our approach is not susceptible to biases caused by epistasis or shared environment. We applied this approach to the analysis of 13 phenotypes in 21,497 African-American individuals from 3 cohorts. For height and body mass index (BMI), we obtained h(2) estimates of 0.55 ± 0.09 and 0.23 ± 0.06, respectively, which are larger than estimates of h(2)g in these and other data but smaller than family-based estimates of h(2)

Improving Nitrogen Fertilizer Management for Yield and N Use Efficiency in Wetland Rice Cultivation in Bangladesh

Achieving high-yielding crops while also improving nitrogen use efficiency is a significant challenge for agricultural production in Bangladesh. We investigated the impacts of applying nitrogen (N) using different management options in wetland rice on a calcareous dark gray soil over three seasons. These included (1) the recommended dose of available N as prilled urea, (2) the recommended N dose plus 25% extra of available N as prilled urea, (3) 25% less than the recommended dose of available N as prilled urea, (4) the recommended dose of prilled urea in 2 t ha−1 cow dung, (5) the recommended dose as urea super granules (USGs) by deep placement, (6) 4 t ha−1 biochar with the recommended dose of prilled urea, and (7) Zero N. It was found that the growth, yield, andN use efficiency (NUE) were significantly different from the results obtained for prilled urea in all the alternative fertilizer options. The deep placement of USG consistently increased plant height, total number of tillers per plant, effective tillers per plant, chlorophyll content, panicle length, grains per panicle, and 1000-grain weight. The yield increases over recommended prilled urea were 5.22% for USG followed by biochar with the recommended dose. Similarly, using the deep placement of USG gave the highest yield and harvest index. In addition, compared to the recommended dose of prilled urea, the deep placement of USG increased NUE by 13%, agronomic N efficiency by 20%, and recovery N use efficiency by 19%. This suggests the rate of N application could be reducedby up to 8% without impacting yield by using deep placement of USG instead of prilled urea. The cost–benefit ratio was higher for the deep placement of USG than all other treatments. Biochar with the recommended dose of prilled urea also showed good results in terms of growth, yield, and NUE (41.8, 43.0, and 41.7, respectively, during three sequential years), but the extra cost of the biocharreduced the cost–benefit ratio. These findings suggest that the deep placement of USG is the best option for improving the yield of rice while also improving N use efficiency

Effect of elevated ozone and carbon dioxide interaction on growth and yield of maize

The effect of elevated tropospheric ozone and carbon dioxide interaction were evaluated on the growth and pro¬ductivity of high quality protein maize (HQPM-1) at the research farm of the Indian Agricultural Research Institute, New Delhi. Maize plants were exposed from emergence to maturity for two years to different ozone levels in non fil¬ter air (NF), charcoal filter air (CF), non-filter air with elevated CO2 (NF+CO2), elevated ozone (EO and EO1), elevated ozone with elevated CO2 (EO+CO2) and ambient control (AC) in open top chambers. Elevated ozone significantly decreased growth attributes of leaf and shoot biomass and leaf area index and the yield attributes. Highest values of all the growth and yield attributes were observed in CF treatment. The photosynthetic rate decreased by 24 to 37% and from 41 to 56% under EO (ambient + 25-35 ppb O3) over NF at tasseling and silking stage respectively. The yield increased by 21 to 31% in the sub ambient ozone levels in the CF treatment over non-filtered control whereas it decreased by 13 and 20 % under EO in both the years respectively. The presence of higher levels of ozone EO1 (ambient + 45-50 ppb O3) however made the plant weak and more susceptible to pest attack, result¬ing in a complete loss in yield. The presence of elevated carbon dioxide along with elevated ozone in the EO+CO2 treatment increased the yield by 9 to 10% over EO alone. Elevated CO2 was able to counter the negative effect of O3 on growth and yield parameters of maize to a certain extent

Sulphur-coated urea reduces greenhouse gas intensity and enhances soil quality in rice cultivation

The Indo-Gangetic Plain (IGP) faces significant challenges related to greenhouse gas (GHG) emissions and declining soil health due to intensive rice-based cultivation systems. This study evaluated the efficacy of enhanced efficiency fertilizers (EEF), including slow-release fertilizer (Sulphur-coated urea, SCU), and nitrification inhibitors (Neem-coated urea, NCU; Karanj-coated urea, KCU) in reducing GHG intensity and improving soil biological activity in rice systems in the IGP. Field experiments conducted over two years assessed yield parameters, GHG emissions, and indicators of soil microbial biomass, nutrient content, and enzymatic activity. NCU reduced CH4 emissions by 11 % and N2O emissions by 16.5 % relative to prilled urea (PU), while SCU and KCU also demonstrated notable emission reductions. Sulphur coated urea demonstrated the lowest greenhouse gas intensity (GHGi) (0.128 kg CO2-eq kg− 1 grain yield), followed by NCU and KCU. All EEFs significantly improved rice grain yield compared to PU, with SCU and KCU recording the highest mean yields (~5600 and ~5560 kg ha− 1, respectively) versus 5010 kg ha− 1 under PU. Additionally, EEFs improved microbial biomass carbon and nitrogen, dehydrogenase activity, and reduced nitrate reductase and urease activity compared to conventional prilled urea (PU), with KCU and SCU showing the greatest improvements and highest net returns. Among the EEFs, SCU consistently achieved the highest yield, lowest GHGi, and overall improvements in soil health, making it a promising alternative for sustainable rice production. Projections indicate that while application of NCU in the IGP region during rice cultivation could reduce the GHGi by 12.2 % while adopting SCU may achieve a 25.8 % reduction, supporting India’s commitment to the Paris Climate Agreement and promoting sustainable agricultural practices in the IGP

Application of additional dose of N could sustain rice yield and maintain plant nitrogen under elevated ozone (O3) and carbon dioxide (CO2) condition

IntroductionGlobal food security is challenged by the increasing levels of air pollutants like ozone (O3) through their impacts on crop productivity. The present study was conducted to quantify the interactive effect of elevated ozone (O3) and carbon dioxide (CO2), on different rice varieties in northern India.MethodsAn experiment was conducted in Genetic H field, Environment science, IARI for two consecutive years (2020 and 2021) during the kharif season, to quantify the impact of elevated O3 and CO2 interaction on productivity, and plant N in three rice varieties (Pusa basmati 1121, Nagina 22, IR64 Drt1) under different nitrogen (N) management practices. Rice crop was grown in Free Air Ozone-Carbon dioxide Enrichment rings (FAOCE) rings with two levels of O3 (elevated 60 ±10ppb and ambient) and two levels of CO2 (elevated, 550±25 ppm and ambient) concentration and their interaction with two N fertilizer treatments i.e., 100% RDN (recommended dose of N) and 125% RDN.Results and discussionElevated O3 significantly decreased physiological parameters like photosynthesis rate, stomatal conductance and transpiration rate of the crop. Grain yield reduced by 7.2-7.5%, in Pusa Basmati 1121 and from 6.9-9% in IR64 Drt1 varieties in elevated O3 treatment as compared to ambient treatment. Yield reduction in Nagina 22 variety was not significant in elevated O3 treatment. Elevated CO2 concentration of 550 ppm was able to fully compensate the yield loss in Nagina 22 variety and partially compensate (3.9-8.0%) in Pusa Basmati 1121 and IR64 Drt1 varieties. Grain N concentration in rice varieties decreased by 10.8-14.7% during first year and by 7.8-20.6% during second year in elevated O3 plus CO2 interaction treatment than ambient. Grain N uptake also decreased (13.2-17.1% in first year and 4.5-22.8% in second year) in elevated O3 plus CO2 interaction treatment as compared to ambient. Application of additional 25% of recommended dose of N improved grain N concentration, grain N uptake as well as available N of soil as compared to 100% RDN treatment in elevated O3 plus CO2 interaction treatment. Additional 25% N dose could help in sustaining rice productivity and quality under elevated O3 and CO2 condition

Evaluating the combined effects of elevated ozone and carbon dioxide on seed-related traits in Indian mustard (Brassica juncea)

An experiment was conducted during winter (rabi) seasons 2020–21 and 2021–22 at ICAR-Indian Agricultural Research Institute, New Delhi, aimed to evaluate the influence of elevated conditions on seed germination in Indian mustard. Three winter Indian mustard (Brassica juncea) varieties (PDZM 31, Pusa Bold, and PM 30) to study the effects of elevated ozone (65 ± 10 ppb), elevated carbon dioxide (550 ± 10 ppm), and their interaction under FAOE, FACE, and FAOCE treatments. The impact of elevated ozone, carbon dioxide, and their interaction on seed-related traits remains scarce and underexplored. The results showed that seed germination traits (germination percentage, speed of germination, uniformity in germination, seedling shoot length, and seedling shoot width) and seed size parameters (seed length and seed width) were negatively affected by elevated ozone at different growth stages of Indian mustard. Additionally, significant changes were observed under elevated CO2. Notably, under interaction treatments, elevated CO2 was found to mitigate the detrimental effects of elevated ozone, providing insights into potential adaptation strategies for mustard cultivation under future climatic conditions

Increasing nitrogen use efficiency by reducing ammonia and nitrate losses from tomato production in Kabul, Afghanistan

Over the past century, the inefficient use of reactive nitrogen (N r ) has raised concerns regarding global food production and planetary sustainability. This study investigates nitrogen (N) losses in tomato production near Kabul, Afghanistan, aiming to improve nitrogen use efficiency (NUE) for enhanced food security and environmental protection. Three fertilizer treatments were tested: (A) animal manure + ¼ dose of chemical fertilizer, (B) night soil + ¼ dose of chemical fertilizer, and (C) full dose of chemical fertilizer, with sub-treatments varying in N application (25% less, 25% excess, and farmers’ practice). A no-fertilizer control treatment was included. Nitrogen losses through ammonia emissions and nitrate–N leaching were monitored, while nitrogen balances and NUE were calculated. The findings revealed that ammonia emissions decreased by 33% in treatment A 2 and by 30% in treatment B 3 compared to surface application. However, nitrate–N leaching peaked at 145 kg N ha −1 in A 2 and 128 kg N ha −1 in B 3 , with positive N balances observed across treatments, the highest being 300 kg N ha −1 in treatment A. NUE ranged from 30% (A and B) to 55% (control), highlighting the widespread overapplication of N in Afghan agriculture. This study demonstrates that efficient N management practices can reduce environmental losses while maintaining tomato yield, offering a novel pathway toward sustainable farming in the region

Managing reactive nitrogen in spring wheat cropping systems: insights from Kabul, Afghanistan

Ammonia (NH₃) volatilization and nitrate leaching contribute to major losses of reactive nitrogen (Nr) in agriculture, leading to global environmental concerns. Effective measures are needed to mitigate Nr losses and improve nitrogen (N)-use efficiency in agricultural practices. This study, conducted in farmers' fields in Shewaki near Kabul City, Afghanistan, during the 2021 spring season, sought to address Nr-losses in agriculture. Nine treatments were organized into three categories: (A) animal manure + chemical fertilizer, (B) night soil + chemical fertilizer, and (C) chemical fertilizer alone, along with an unamended control. Chemical fertilizer and manure were applied at varying rates (±25% and a recommended rate) using both surface and sub-surface application methods. Sub-surface application reduced NH₃ emissions by 55% compared to surface application. Treatment group 'A' had a 32% NH₃ loss, while the unamended control (receiving N from irrigation water and dust only) showed a 13% loss. For nitrate leaching, group 'B' showed the highest loss, followed by group 'C'. Overall, agronomic practices reduced N-losses significantly, resulting in a net positive N-balance. Nuse efficiency was highest in group 'C' at 130%, followed by groups 'B' and 'A'. The findings suggest that sub-surface application techniques are effective in reducing N-losses and enhancing N-use efficiency, and highlight the potential to improve nutrient use efficiency by adjusting fertilizer and manure inputs in similar agricultural systems