Shift In Flora Research Articles

Association of Preterm Delivery with Urinary Tract Infection and Preventive Role of Ceftriaxone

Urinary tract infections (UTIs) are the leading cause of maternal morbidity and poor birth outcomes. Pregnancy changes increase UTI risk. A larger bladder, less tone, and a shift in vaginal flora are changes. Eradicating pathogens in the urogenital tract can lower the risk of infection-related preterm labor by stopping the progression of asymptomatic bacteriuria into a more serious infection. Objective: To determine the association of preterm labor with urinary tract infection and the preventive role of ceftriaxone. Methods: A case-control study was conducted at the Department of Obstetrics and Gynecology, Khyber Teaching Hospital, Peshawar, from 14 December 2021 to 10 June 2022. 130 pregnant women who met the selection criteria were recruited from the hospital's post-delivery wards. The participants were then separated into a case group and a control group. Protocols for treating UTIs in female were followed. Ceftriaxone was administered to the group of participants who were UTI-positive. Results: The mean age of female in the case group was 28.88 ± 7.18 and in the controls group was 28.97 ± 6.85 years. The mean gestational age at delivery in cases was 34.28 ± 1.34 weeks and in controls 39.4 ± 1.11 weeks. There was a significant association between preterm labor and urinary tract infection (p= <0.05). Administration of ceftriaxone reduced the risk of preterm labor (p=0.001). Conclusions: It was concluded that there is a significant correlation between UTIs and premature labor and ceftriaxone plays an important role in reducing preterm delivery of UTI patients.

Weed flora shift as affected by cropping systems

Weed flora shift as affected by cropping systems

Effect of Zero Tillage and Different Weed Management Practices in Direct Seeded Rice (Oryza sativa L.) in Indo Gangetic Plains: A Review

Millions of rural and urban residents depend on the rice-wheat cropping system of the Indo-Gangetic plains (IGP) for their food security and means of subsistence. About 18 million hectares (m ha) of rice (Oryza sativa L.) and wheat (Triticum aestivum L.) are rotated across Asia, of which 13.5 m ha are in the Indo-Gangetic Plains (IGP) of India. This agricultural system’s viability is currently in jeopardy due to static yields of both wheat and rice and a decline in total factor productivity. The North West IGP's high input crop culture has allowed weeds to dominate the weed flora, including P. minor in wheat and Echinochloa crus-galli L. in rice. Farmers in North West India have largely used zero tillage for growing wheat, and recently, farmers in the eastern IGP have done the same. Perennial weeds in the Eastern Indo-Gangetic Plain, such Cynodon dactylon L. and Cyperus rotundus L. can occasionally be a nuisance under zero tillage. As an alternative to puddled transplanted rice, the focus is currently on dry direct-seeded rice and machine transplanting of non-puddled rice. As a result of changes in tillage, crop establishment techniques, water use, and weed control brought on by the switch from transplanted rice to direct seeded rice, weed composition and diversity frequently vary. In nations where DSR is frequently used, weedy rice has become a significant concern. Using the Zero Tillage DSR system, certified seed, cultivars that are weed-competitive, stale seedbed procedures, living mulches, and chemical and biological weed control might change weed-crop competition in the crop's favour. However, more research on emergence characteristics and mulching effects of different crop residues on key weeds under zero tillage, cover cropping, and breeding crops for weed suppression will strengthen nonchemical weed management programs. In this review, we examine the extent of weed infestation, weed flora shift and the non-chemical alternative weed management in DSR.

Menstrual Blood as a Diagnostic Specimen for Human Papillomavirus Genotyping and Genital Tract Infection Using Next-Generation Sequencing as a Novel Diagnostic Tool.

Menstrual blood (MB) is a convenient specimen type that can be self-collected easily and non-invasively by women. This study assessed the potential application of MB as a diagnostic specimen to detect genital tract infections (GTIs) and human papillomavirus (HPV) infections in women. Genomic DNA was extracted from MB samples. Pacific Bioscience (Pacbio) 16S ribosomal DNA (rDNA) high-fidelity (HiFi) long-read sequencing and HPV PCR were performed. MB samples were collected from women with a pathological diagnosis of CIN1, CIN2, CIN3 or HPV infection. The sensitivity and positive predictive value (PPV) of high-risk HPV detection using MB were found to be 66.7%. A shift in vaginal flora and a significant depletion in Lactobacillus spp. in the vaginal microbiota communities were observed in the MB samples using 16S rDNA sequencing. In this study, we demonstrated that MB is a proper diagnostic specimen of consideration for non-invasive detection of HPV DNA and genotyping using PCR and the diagnosis of GTIs using metagenomic next-generation sequencing (mNGS). MB testing is suitable for all women who menstruate and this study has opened up the possibility of the use of MB as a diagnostic specimen to maintain women's health.

Interpretation of vaginal metagenomic characteristics in different types of vaginitis.

Vaginitis is one of the most common gynecological diseases, mostly caused by infections of pathogens such as Candida albicans and Gardnerella vaginalis. In recent years, it has been found that the stability of the vaginal flora plays an important role in vaginitis. Furthermore, the abundant Lactobacillus-producing rich lactic acid in the vagina provides a healthy acidic environment such as Lactobacillus crispatus. The metabolites of Lactobacillus can inhibit the colonization of pathogens. Here, we collected the vaginal samples of patients with bacterial vaginitis (BV), vulvovaginal candidiasis (VVC), and BV combined with VVC to discover the differences and relationships among the different kinds of vaginitis by metagenomic sequencing. Furthermore, because of the importance of L. crispatus in promoting vaginal health, we isolated multiple strains from vaginal samples of healthy females and chose the most promising strain with potential probiotic benefits to provide clinical implications for treatment strategies.

Changes in the weed flora of cotton fields in the Eastern Mediterranean region of Turkiye

Cotton is the most dominant field crop, especially in higher soil saline parts of the Eastern Mediterranean region of Türkiye. This study aims to determine the current statues of weed flora of cotton fields in the East Mediterranean region, to compare it with weed flora in 1991-1992 and to understand whether a weed flora shift has occurred in these fields. Eighty-two cotton fields were surveyed during the growing season (July and August) in 2018, and thirty-seven weed species distributed in 17 families were found in the survey fields, where 18, 23, 17, and 33 of them were recorded in the Kahramanmaraş, Hatay, Mersin, and Adana provinces, respectively. Canonical correspondence analysis revealed that the phytosociological composition of the cotton fields was significantly related to the P content of the soil, average temperature, and cumulative rainfall. The current weed survey also indicated that these fields were under the threat of some invasive alien plant species that had not been found in previous surveys, such as Ipomoea triloba L., Amaranthus palmeri L., and Cucumis melo var. agrestis Naudin. Although cotton fields in the region were reduced by two-thirds in 2018 compared to 1991-1992, weed richness increased. Weed flora shifts were influenced by crop, crop rotation, herbicide use, irrigation, and landscape factors of cotton fields in the East Mediterranean Region of Türkiye.

Biogeography and environmental preferences of Butia yatay (Mart.) Becc.

During the Quaternary, Chaco Phytogeographic Domain (Chaco) flora in subtropical South America experienced temperature and humidity fluctuations, primarily driven by wind dynamics, leading to significant shifts in species distribution. The palm Butia yatay is endemic to the Chaco and thrives in areas characterized by a warm-rainy climate and mostly restricted to sandy soils. To investigate the current geographic distribution of suitable habitat for B. yatay while assessing the significance of soil variables, we employed two distinct algorithms in species distribution modeling (SDM). We also determined whether the distribution of B. yatay has changed since the Pleistocene and whether these changes align with previously proposed Pleistocene refugia. In the present SDMs, we considered two separate sets of predictors, one set with bioclimatic variables only and the other set with bioclimatic topographic and soil variables. Additionally, we reconstructed the historical geographic distribution of suitable habitats using bioclimatic data. Our results suggested that the primary determinants of B. yatay's current distribution include precipitation and temperature of the driest month and soil cation exchange capacity. Incorporating soil variables affected the estimated size and range of suitable areas. Projections into the past indicated similar suitable habitat distributions during interglacial periods compared with the present. During the Last Glacial Maximum, climatically suitable habitat may have shifted northward, partially overlapping with previously suggested Pleistocene refugia located between the Paraná and Uruguay Rivers. These findings indicate the main factors driving the distribution and ecology of B. yatay and enhance understanding of subtropical flora shifts during the Quaternary. The approach also may prove valuable for other studies within the Chaco.

Response of the Patagonian floras to climatic cooling during Oligocene−Miocene transition and the expansion of Antarctic glaciation

Pulses of Antarctic ice sheet expansion and associated climatic deterioration are thought to have driven major shifts in the world's flora during the Cenozoic Era. However, the rarity of fossils from well-constrained sedimentary strata in high palaeolatitudes makes it difficult to explore to these vegetation shifts directly. In this study, we infer changing patterns of floristic richness through the Oligocene−Miocene cooling event (∼23 Ma), based on analysis of terrestrial palynological samples in the radiometrically-constrained sediments of the Río Guillermo Formation of southern Patagonia. Our fossil assemblages include plant families typical of modern Magellanic subpolar forests such as Nothofagaceae, Podocarpaceae, Araucariaceae, and Myrtaceae. Adjusted for sample completeness (or coverage), our floristic richness estimates are, on average, higher than those from modern subpolar forests yet considerably lower than any other Paleogene or Neogene palynological records published elsewhere from the continent. The transient Oligocene−Miocene cooling episode, whose effects were probably intensified in southern Patagonia due to its close proximity to the glaciated Antarctic Peninsula, may have contributed to the steep decline in floristic richness. We infer that most Gondwanan plant relicts that survived across the Oligocene−Miocene transition endured through subsequent Neogene climatic fluctuations and contribute to present-day Magellanic subpolar forests. Our study highlights how precisely-dated fossil assemblages and robust diversity methods can be used to track biodiversity shifts in response to past climate change.

Weed Management Studies in Wheat (Triticum aestivum L.) Through New Herbicide Molecule Aclonifen 600 SC under Climate Changing Era

Changing climate aggregates, the problem of weed management by rapid weed flora shift and resistance development. In these conditions, the best option is to use new herbicide molecules with a diverse mode of action and a wider application time window. Thus, an herbicidal trial was conducted during the Rabi 2019-20 at Agricultural Research Farm, BHU, Varanasi. The experiment was laid out in RCBD design with 8 treatments viz., control (W1), aclonifen 600SC @ 1.05 kg a.i./ha PE (W2) and early POE (W5),aclonifen 600SC @ 1.2 kg a.i./ha PE (W3) and early POE (W6), pendimethalin 30% EC @ 1.25 kg a.i./ha PE (W4), sulfosulfuron 75% WG @ 0.025 kg a.i./ha POE (W7), Farmer practice-2 hand weedings at 20 and 40 DAS (W8) and replicated thrice. Among different treatments aclonifen 600 SC @ 1.25 kg a.i./ha as pre and early post-emergence applied treatments recorded minimum weed density, weed dry matter production, highest weed control efficiency and crop persistence index. The same treatments registered better crop growth performance, and profitable yields.

Saccharomyces boulardii protects against murine experimental colitis by reshaping the gut microbiome and its metabolic profile.

Saccharomyces boulardii (S. boulardii) has shown clinical beneficial effect in inflammatory bowel diseases recently. However, the underlying mechanisms remain incompletely understood. The aim of present study was to tested whether S. boulardii targets gut microbiota to protect against the development of experimental colitis in mice. Female C57BL/6 mice were gavaged with S. boulardii for 3 weeks before being challenged with dextran sulphate sodium to induce ulcerative colitis. Bodyweight, diarrhea severity, intestinal permeability, colonic histopathology, colonic inflammatory status, and epithelial cell death of mice were examined. The fecal microbiota and its metabolomic profiles were detected by 16S rDNA sequencing and UPLC-MS, respectively. Supplementation with S. boulardii significantly prevented weight loss and colon shortening, lowered colonic inflammation, ameliorated epithelial injury, and enhanced the intestinal barrier integrity in colitis mice. By inhibiting the abundance of pathogenic bacteria and increasing the probiotics abundance, S. boulardii improved the microbial diversity and restored the microbiota dysbiosis. Moreover, it also modulated microbial metabolome and altered the relative contents of metabolites involving amino acids, lipids, energy and vitamin metabolisms. These yeast-driven shifts in gut flora and metabolites are were associated with each other and with the inflammation profile in colitis. Collectively, S. boulardii exerts protective effects on colitis in mice by reshaping gut microbiome and its metabolic profile, indicating it as a promising therapeutic avenue.

Climate, atmospheric deposition and catchment process interact to trigger recent diatom community reorganization in alpine lakes of the eastern monsoonal region of China

Atmospheric deposition and climate change are altering alpine lake ecosystems at an accelerating rate. Biotic responses to the interactions of multiple stressors are underexplored in alpine lakes. This study explored diatom responses to climate change and nutrient supply based on multi-proxy sedimentary records in Erye and Sanye Lakes of the Taibai Mountain at the boundary between the subtropical and temperate climate zones of eastern China. Diatom communities of the two lakes shifted from large-sized benthic taxa to small fragilarioid species at the beginning of the 21st century, synchronous with an increase in diatom accumulation rate. Redundancy analyses showed that diatom communities were significantly correlated with catchment processes and nutrient inputs in both lakes, as well as climate warming in the upstream lake. Partial least squares path modelling revealed that catchment processes were more important than direct effects of climate warming and nutrient supply for explaining the observed shifts in diatom flora in the two alpine lakes. The comparison with diatom records in similar alpine lakes in the East Asian monsoon region reveals that responses of alpine lake ecosystems to warming and atmospheric deposition vary with different catchment settings and lake morphometry. Given that these alpine lakes serve as important water sources, recent biotic reorganization suggests that the protection of headwater systems should be given high priority, especially in rapidly developing and densely-populated regions.

Cervicovaginal cytology, HPV testing and vaginal flora in transmasculine persons receiving testosterone.

Testosterone is one of the strategies that transmasculine persons can elect in order to align physical traits to their gender identity. Previous studies have shown morphologic changes in the genital tract associated with testosterone. Here, we aim to evaluate cervicovaginal cytology specimens (Pap tests) and high-risk HPV (HR-HPV) testing from transmasculine individuals receiving testosterone. This is a retrospective cohort of 61 transmasculine individuals receiving testosterone from 2013 to 2021. Cytologic diagnoses from 65 Pap tests were correlated with HPV status and histologic follow-up and compared with the institutional data and a cohort of cisgender women with atrophic changes. The median age was 28 years and median time of testosterone use was 3 years. Transmasculine persons showed significantly higher rates of HSIL (2%) and unsatisfactory (16%) when compared with the institutional data and atrophic cohort of cisgender women. After reviewing slides of 46 cases, additional findings were noted: atrophy was present in 87%, glycogenated cells were seen in 30%, and Lactobacilli were substantially decreased in 89%. Among 32 available HPV tests, 19% were positive for HR-HPV and 81% were negative. On histologic follow-up, all HR-HPV-positive cases with abnormal cytology showed HSIL, while none of the HPV-negative cases revealed HSIL. Our study cohort demonstrated a high percentage of abnormal Pap tests in transmasculine persons receiving testosterone. Testosterone seems to induce changes in squamous cells and shifts in vaginal flora. HR-HPV testing can be a useful adjunct in the workup of abnormal Pap tests from transmasculine individuals.

Improved Plasma Lipids, Anti-Inflammatory Activity, and Microbiome Shifts in Overweight Participants: Two Clinical Studies on Oral Supplementation with Algal Sulfated Polysaccharide.

Seaweed polysaccharides in the diet may influence both inflammation and the gut microbiome. Here we describe two clinical studies with an Ulva sp. 84-derived sulfated polysaccharide—“xylorhamnoglucuronan” (SXRG84)—on metabolic markers, inflammation, and gut flora composition. The first study was a double-blind, randomized placebo-controlled trial with placebo, and either 2 g/day or 4 g/day of SXRG84 daily for six weeks in 64 overweight or obese participants (median age 55 years, median body mass index (BMI) 29 kg/m2). The second study was a randomized double-blind placebo-controlled crossover trial with 64 participants (median BMI 29 kg/m2, average age 52) on placebo for six weeks and then 2 g/day of SXRG84 treatment for six weeks, or vice versa. In Study 1, the 2 g/day dose exhibited a significant reduction in non-HDL (high-density lipoprotein) cholesterol (−10% or −0.37 mmol/L, p = 0.02) and in the atherogenic index (−50%, p = 0.05), and two-hour insulin (−12% or −4.83 mU/L) showed trends for reduction in overweight participants. CRP (C-reactive protein) was significantly reduced (−27% or −0.78 mg/L, p = 0.03) with the 4 g/day dose in overweight participants. Significant gut flora shifts included increases in Bifidobacteria, Akkermansia, Pseudobutyrivibrio, and Clostridium and a decrease in Bilophila. In Study 2, no significant differences in lipid measures were observed, but inflammatory cytokines were improved. At twelve weeks after the SXRG84 treatment, plasma cytokine concentrations were significantly lower than at six weeks post placebo for IFN-γ (3.4 vs. 7.3 pg/mL), IL-1β (16.2 vs. 23.2 pg/mL), TNF-α (9.3 vs. 12.6 pg/mL), and IL-10 (1.6 vs. 2.1 pg/mL) (p < 0.05). Gut microbiota abundance and composition did not significantly differ between groups (p > 0.05). Together, the studies illustrate improvements in plasma lipids and an anti-inflammatory effect of dietary SXRG84 that is participant specific.

Dietary titanium dioxide particles (E171) promote diet-induced atherosclerosis through reprogramming gut microbiota-mediated choline metabolism in APOE-/- mice

Food-grade titanium dioxide (E171) has been reported to induce changes in some intestinal metabolites related to development of atherosclerosis (AS). However, little is known about the effects of chronic dietary intake of E171 on AS development, particularly in AS-prone populations with high-choline western diet (HCD). Herein, we disclosed that E171 obviously exacerbated HCD-induced AS through increasing production of trimethylamine (TMA) and pro-atherogenic trimethylamine-N-oxide (TMAO) via remodeling gut microbiota structure in APOE-/- mice. Oral administration of 40 mg/kg E171 daily for 4 months significantly increased the atherosclerotic lesion area, especially in the HCD group. Mechanistic studies revealed that E171 induced much more TMAO production by increasing the gut microbial expression of choline TMA lyases (CutC/D), which converted dietary choline to TMA by a glycyl radical reaction. The 16S rDNA sequencing analysis demonstrated that bacterial strains expressing CutC/D were enriched by E171 in HCD-fed mice. In contrast, gut microbiota depletion eliminated the impact of E171 on choline/TMA/TMAO pathway and AS progression, indicating gut flora shifts were responsible for the exacerbation effects of E171 ingestion on HCD-induced AS. All the results emphasized the alarming role of E171 on AS progression and stated the importance of reevaluating the impact of food additives on the development of chronic diseases.

Prevalence and Distribution of Weed Flora in Some Major Sugarcane Growing Areas of Southern Guinea Savanna, Nigeria

Weed population survey was undertaken to determine prevalence and distribution of weeds, and asses weed flora shift in major sugarcane growing areas in Southern guinea savanna of Nigeria. The selected areas surveyed are namely Badeggi, Sulti, and Isenyi. The Sugarcane fields were assessed using 1.0 m x 1.0 m quadrat placed randomly at vegetative stage. Weed seedlings in each quadrat were clipped at the soil level and identified according to standards. Result revealed that a total of 38 weed species were recorded. Graminaea and compositae were most abundant and diversified families based on the number of species recorded. Individual weed species shows variation in their abundance, dominance and frequency. The most frequent weed species in the Sugarcane fields irrespective of the soil, climate and crop varieties were Hyptis suaveolens, Paspalum scrobiculata, Kyllinga squamulata, Dactylactenum aegypium and Cynadon dactylon and were considered as the most important species in the surveyed areas. From Similarity indices, variations were observed between locations. Accordingly, areas having similarity indices more than 60 % indicate similarities in weed community. Thus, when devising a weed control strategies same control option should be considered for the location that have similar weed flora and vise-versa.

Caloric Restriction Alleviates Radiation Injuries In A Sex-Dependent Fashion

Background: There remain unmet clinical needs for safe and effective regimen to fight against radiation injuries from medical irradiation or accidental exposure. Intestinal microbes play important roles in radiation damage. Diet is an efficacious mediator to educate the gut microbiota directly. Methods: In this case, we investigated whether 30% reduced calorie might ameliorate radiation enteritis and hematopoietic toxicity. Male and female C57BL/6J mice were either fed ad libitum (AL) or caloric restriction (CR) preconditioning for 10-day and then exposed to total body radiation (TBI) or total abdominal radiation (TAI). Findings: Gross examinations showed that short-term CR pretreatment restored hematogenic organs and improved intestinal architecture in both sexes of mice. Intriguingly, CR mitigated radiation-induced systemic and enteric inflammations in females, while the gut barrier function improved in irradiated male mice. 16S rRNA high-throughput sequencing was performed and showed that after 10-day of CR preconditioning, proinflammatory microbes including Helicobacter and Desulfovibrionaceae were lessened in female mice, while an enrichment of short-chain fatty acids (SCFAs)-producing bacteria such as Faecalibaculum, Clostridiales and Lactobacillus was observed in males. Gut flora shifts by fecal microbiota transplantation (FMT) or antibiotic administration counteracted CR-elicited radiation tolerance of both male and female mice, further demonstrated that the radioprotection of CR depends on the CR-restructured sex-specific gut microbiota configuration. Interpretation: Together, our findings provide new insights into CR in clinical applications, and indicate that short-term CR diet prior to radiation modulates the gut microbiota in a sex-dependent fashion, protecting male and female patients against the side effects caused by accidental or iatrogenic radiation challenge. Funding: Natural Science Foundation of China [81730086, 81872555, 82003399]; Science Foundation for Distinguished Young Scholars of Tianjin [20JCJQJC00100]; Drug Innovation Major Project of China [2018ZX09711001-007-008]. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: The animal use protocol has been reviewed and approved by the Animal Ethical and Welfare Committee (AEWC)

Herbicide mixture mediated soil environment analysis in wet direct-sown rice

Direct-sown rice is the possible alternative to the conventional puddled transplanted rice as it saves resources viz. water, labour and time. Pre-germinated (sprouted) seeds are sown on puddled soil in wet direct-sown rice. But weed infestation is the major yield compromising factor under this environment as the weeds emerge simultaneously with the rice and compete from the beginning. Among the weed control methods, herbicide-based weed control is the most effective and efficient method. However single herbicide application in a long run leads to weed flora shift and development of herbicide resistance in weeds. In contrast, herbicide mixtures with different mode of action are the possible alternative to reduce the herbicide resistance and to broaden the weed control spectrum season long. But soil environment aspect is important for sustainable rice farming using herbicide mixtures. This investigation was done in Research farm of ICAR – National Rice Research Institute, Cuttack, Odisha in wet season of 2016. The experiment was laid out in randomized complete block design with nine treatments viz. herbicide mixture florpyrauxifen-benzyl + cyhalofop-butyl in four doses i.e. 120, 150, 180 and 360 g/ha; florpyrauxifen-benzyl in two doses i.e. 25 and 30 g/ha; bispyribac-sodium at 30 g/ha; weed free and weedy check; replicated thrice. Soil environment parameters viz. microbial-biomass carbon, FDA hydrolase activity, dehydrogenase activity and urease activity were studied before, 4, 10, 20 and 30 days after herbicide treatments. The herbicide mixture florpyrauxifen-benzyl + cyhalofop-butyl at 150 g/ha (4.91 t/ha) was found to be the most effective herbicide showing no detrimental effect on soil environment of wet direct-sown rice after 10 days of application and yielding at par with the weed free (5.27 t/ha).

Herbicide resistance in weeds and its management strategies

Weeds are much older than crop cultivation for food, fuel, fibre and shelter. Weed management is a big task for production of various crops. At present time, herbicides are most popular and effective means for weed management due to their higher efficacy and time saving nature. But their continuous and indiscriminate use has created several problems like weed flora shift, herbicide resistance and environmental hazards. Out of these, herbicide resistance is most serious problem of present time. Currently there are 480 cases of herbicide resistance in 252 plant species. There are various types of herbicide resistance such as cross resistance, multiple resistance, partial resistance, full resistance etc. Herbicide resistance has become a major issue at world level, and number of resistant biotypes is increasing continuously at very rapid rate. Therefore, some alternate management practices such as cultural, mechanical and biological methods should be integrated in weed management program to combat this problem. A proper understanding of development and mechanism of resistance (altered target sites, rapid metabolism and sequestration) would help us for its management. With the help of various physiological and biochemical studies, some resistant screening techniques should be developed for yielding quick results. This paper provides information on status of herbicide resistance, development of resistance, factors affecting development of herbicide resistance in weeds, resistance mechanisms and its management.

Enhancing productivity of sugarcane by successful weed management through integration of brown manuring of Sesbania and pre and post emergence herbicides

Field experiments were conducted to evaluate the combined effect of brown manuring with post emergence herbicide on weed management in planted sugarcane. Weeds are one of the major biotic stress and its management was the very costliest agronomic input in the successful crop production. Weeds can cause yield reduction in sugarcane up to 40%. Indiscriminate use of herbicides can accelerate weed flora shift and resistance besides causing environmental pollution and non-target toxicities and. Brown manuring is a no till version of green manuring using a post emergence herbicide. For brown manuring, Sesbania is grown as intercrop with sugarcane for initial 35 days, and then, is knocked down by 2,4-D. BM had multiple benefits including weed management. In Sugarcane its wider inter row space and its initial slow growth would allow to formulate an integrated weed management (IWM) module with brown manuring and herbicide. Therefore, this experiment was undertaken at Agricultural Collage and Research Institute, Madurai during 2016 to 2018 to evaluate the integrated effect of brown manure and herbicide on weed management in sugarcane. Among nine treatments, three were BM of sesbania and three were in- situ incorporation of sesbania, involving one intercultural operation at 90 DAP (Hand hoeing; Metribuzin: halosulfuron application). In addition, three controls, namely atrazine 1 kg /ha + power weeeding at 45 & 75 DAP, hand weeding twice and unweeded control were also adopted and the experiment was laid out in a randomized block design with three replications. A pre-emergence application of pendimethalin 2.0 kg/ha was made in all sesbaniarasied treatments. The results showed that application of pendimethalin 2.0 kg ha-1 + Sesbania (brown manuring) + hand hoeing at 90 DAP recorded minimum number of weeds and weed dry weight. The higher weed control efficiency (78.96%), cane yield (100.5 t /ha) and benefit cost ratio (2.72) were found with PE application of Pendimethalin + Sesbania(Brown manuring) + hand hoeing at 90 DAP compared to POE herbicides and insitu incorporation of Sesbania.

In-situ paddy straw management practices for higher resource use efficiency and crop productivity in Indo-Gangetic Plains (IGP) of India

The large scale adoption of long duration coarse grain rice varieties and combine harvesting have increased the incidences of in-situ rice residue burning in Indo-Gangetic Plains (IGP). Crop residue burning in addition to causing environmental pollution, is also responsible for loss of precious nutrients (complete nitrogen, about one fourth of phosphorus & potash and about three fourth of sulphur) and efficacy of soil active herbicides. The alternatives to rice residue burning are its removal, incorporation or retention. The in-situ management options are better and further, retention is more advantageous than incorporation in term of energy, time and cost effectiveness. In addition, the surface retention has a series of positive effects, such as, moisture conservation, weed suppression, temperature moderation, and improved soil health. Residue management practices (surface retention or incorporation) also influence the nutrient availability, crop water requirement, weed dynamics, herbicide efficacy, insect-pest infestation and mitigation of climate change effect on long term basis. Hence, the agronomic practices need to be adjusted to prevent temporal nitrogen immobilization, hindrance in precise seeding, weed flora shift, and new insect-pest incidents. Suitable machineries for seeding and harvesting are of paramount importance for proper crop establishment under in-situ residue management practices. Combines fitted with straw management system for uniform spread of straw help in efficient running of conservation agriculture (CA) seeding machines like Turbo Happy Seeder and Rotary Disc Drill. Moreover, for smooth running of CA machinery, the height of anchored straw should be kept as much as possible, so that lesser loose straw is present. The adoption of CA practices (no-tillage and residue retention) in wheat under rice-wheat system can help in improving wheat yield by advanced sowing and reduced problem of Phalaris minor Retz. Moreover, fertilizer application method and timing needs to be fine tuned under in-situ residue management options. The nitrogen top dressing should be done just before irrigation to avoid interception by surface retained residue which can enhance volatilization and immobilization losses of nitrogen. Higher efficacy of pre-emergence herbicides in surface retained residue scenario could also be realized by increasing the spray volume along with modifying the application time and placement of herbicides. Therefore, a paradigm shift in agronomic practices, with respect to paddy straw management, is required for enhancing system productivity and resource use efficiency. DOI: http://doi.org/10.25174/2249-4065/2019/96323