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Home > Weed Population Dynamics and Wheat Productivity under Different Tillage Systems in Pothwar

Weed Population Dynamics and Wheat Productivity under Different Tillage Systems in Pothwar

Thesis Info

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Author

Safdar Ali

Program

PhD

Institute

Pir Mehr Ali Shah Arid Agriculture University

City

Rawalpindi

Province

Punjab

Country

Pakistan

Thesis Completing Year

2015

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/6872/1/Safdar_Ali_Agronomy_PMAS_2015.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727672177

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Agriculture of Pothwar region is mainly rainfed and the small farmers of this area do not get sustainable income from the farmland due to inconsistent and erratic rainfall. Thereore, a two-year field study was carried out at University Research Farm of Pir Mehr Ali Shah-Arid Agriculture University Rawalpindi located at Mandra-Chakwal Road in district Rawalpindi of Pakistan, to investigate the effect of different tillage practices and sowing years on weed seed bank dynamics and above ground weed flora in rainfed wheat. This study was also aimed at to find out the most efficient tillage practice that conserves the soil moisture for longer period and is economically acceptable to the farming community of Pothwar Region. At the same time it was expected that this investigation would help us to meet the challenges of rainfed wheat of Pothwar Region. Moreover, the information collected based upon this study especially weed flora and soil weed seed bank could be utilized for planning better weed management strategies in rainfed crops in future. Different tillage combinations were included on: T1 = Conventional Tillage (1MB Plowing + 8 Cultivations), T2 = No-till + *Glyphosate, T3 = 1MB Plowing + *Glyphosate, T4 = 1MB Plowing + 4 Cultivations, T5 = Disc Harrowing + *Glyphosate, T6 = Disc Harrowing + 4 Cultivations, T7 = Chiseling + *Glyphosate. Soil samples were collected before sowing to define the soil. The experiment was laid out in randomized complete block design (RCBD) with four replications. The effects of treatments were recorded on weed population density, weed population frequency, weed ground coverage, weed dry biomass, weed relative density, weed relative frequency, weed relative ground coverage, weed relative dry weight, weed relative abundance, summed dominance ratio and 29 importance value index of weeds. The data on yield and yield components of wheat viz. number of fertile tillers (m-2) at maturity, spike length (cm), number of spikelet spike-1, number of kernels spike-1,1000-kernel weight, aerial biological yield (t ha-1) and grain yield (t ha-1) were collected at harvest. Soil samples were collected and analysed accordingly to record data for soil parameters like soil moisture content, soil bulk density, soil porosity, organic matter, soil available nitrogen, soil available phosphorus and soil extractable potassium to evaluate the soil properties at pre and post experimentation. Data were analyzed by using MSTAT-C software on computer and treatment means were compared with least significance difference test (LSD) at 5% level of probability. The input and output data was collected for economic evaluation (partial budget, dominance analysis and marginal rate of return analysis) to identify the most affordable tillage combination. Results illustrated that the weed seed density was found maximum (29476) in zero tillage system. The study also revealed that there were small differences of weed seed density under different tillage systems, but the minimum number of seeds was found in reduced tillage systems i. e. T1 (21419) and T4 (22513). The vertical distribution of weed seeds indicated that the highest number of weed seeds (54.99 %) was observed at upper soil layer 0-10 cm, while the least (16.33 %) in lower soil layer 21-30 cm as compared to middle layer 11-20 cm having (28.54 %) seeds. Overall the higher seed density (28032) was observed at post-harvesting of wheat as compared to pre-sowing of wheat (21828) in all the tillage systems during both years of experimentation which could be the result of poor weed control during crop growth and development period. Chenopodium album, Asphodelus tenuifolius and Fumaria indica were considered as the dominant weed 30 community followed by Euphorbia helioscopia, Convolvulus arvensis and Melilotus indica in the overall soil weed seed bank. The weed flora population density, frequency, dry weight and ground coverage were found maximum under T6, T7, T5 and T4 treatments; whereas, these parameters were minimum under T1 which reflects the system’s controlling effect on weed flora and thus resulted in the higher yield. Soil properties were improved in reduced tillage systems i. e. T4 and T6 (conservation tillage systems), but the crop germination and establishment was best under conventional tillage and T3 (according to cluster analysis). The reason of low seedling emergence under conservation tillage systems was probably due to inadequate availability of soil moisture and nutrients well in time. The highest yield (3.5132), (3.1242) t ha-1 and net benefit (888.92), (839.35) $ ha-1 were obtained in case of conventional tillage (T1) followed by reduced tillage (T4) according to partial budget analysis. So, on the base of above mentioned facts further experimentation is recommended on integrated weed management under conservation tillage systems for controlling soil weed seed bank and above ground weed flora for obtaining higher yields, but conventional tillage is still recommended for obtaining higher net benefit. The management of weed flora through integrated weed management under conservation systems may decrease the weed crop competition and improve the moisture and nutrients availability to crop that may increase the crop yield.
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سلام

سلام
جس نے خواب کے دین۔۔۔سحر کے ایمان کو!
روشن استعاروں میں گونجتی اذان کو!
چاہتوں کے شفیق موسموں میں سمو کر!
چاروں سمتوں کے سنگم پر۔۔۔
تطہیر کساء کا پانچواں چراغ روشن کیا
اس حسینؑ ابن حیدر پہ لاکھوں سلام
جس نے موت کی نبض پر ہاتھ رکھ کر۔۔۔!
نوک نیزہ پہ سورہ کہف کی!
توریت والانجیل کی گرھیں کھول دیں
سرمئی لوح کی رگوں میں سبز زندگی بھرتے ہوئے!
جس نے میزان حق میں!
در ِ وفا ۔۔۔شہر وفا کی آبرو تول دی
اس حسینؑ ابن علی ؑ پہ لاکھوں سلام
بنتِ محمدؑ و علی ؑ پہ درود و سلام

میں مختلف خیالوں میں الجھا ہوا تھا۔ لیکن بہلول نے محبت کی باتوں میں مختلف تلازموں کو واضع کرنا شروع کر دیا تھا۔ میں انسانی نمود اختیار میں محبت کی داخلی اور خارجی کیفیتوں میں جنگ سے کتراتے ہوئے،۔۔۔خیال، آرزو اور چاہت کے دامن تھامتے ہوئے، تنہائی پہ فریفتہ گزرتے لمحوں کے درمیان احساس تازگی کی وسعتوں میں جو بھی سوچتا۔ وہ نثری نظم یا نثم کی شکل میں ہی سوچتا۔ حالانکہ میرنے نزدیک نثری نظم اپنی شکل، کرافٹ اور ’’انزلنا ھو فی لیلۃ القدر‘‘ کی ہمرا ز نظر آتی ہے۔ جب کہ نثم کے نام کو عقلیہ کی تخلیقی جامعات میں اصلاحی دائرے میں ملنساری کی تہذیب کے طرز عمر کی لمبی مسافتوں کے بعد سامنے لایا گیا ہے۔
ان دونوں اصناف یا ایک ہی صنف کے دو نام کہہ دیا جائے۔ مجھے اس سے کوئی مسئلہ نہیں۔ لیکن ریاض مجید کے حوالے سے اکثر مختلف شعراء سے باتیں ہوتی رہی ہیں۔ اس میں بحث کا لفظ جان بوجھ کر حذف کیا ہے۔ اس میں جناب خالد احمد صاحب، مقصود عامرصاحب، جواز جعفری صاحب،انہیں نثم سے بھی کوئی مسئلہ نہیں۔
جناب وجہی صاحب، اقبال سید صاحب، روش ندیم صاحب،...

Welcome Note from Editor-in-Chief

It is with great pleasure that I write this editorial to welcome you to the first issue of this new International journal, “Pakistan Biomedical Journal” (PBMJ). The topics covered by the journal are certainly broad and interesting. Biomedical science is a collection of applied sciences that help us understand, research, and innovate within the field of healthcare. It includes disciplines like molecular biology, clinical virology, bioinformatics, and biomedical engineering, among others. It's designed to apply the biological sciences to advance not only individual health but also the area of public health. Biomedical Research can help health professions better understand things like the human body and cell biology, making advances in our understanding of epidemics, health initiatives, and human health in the age of longer life expectancy. It aids our understanding of infectious disease and provides research opportunities into some of our most troubling health issues. The journal will continue to publish high quality clinical and biomedical research in health and disease later in life. Peer review will remain a vital component of our assessment of submitted articles.I am very happy to have a team of excellent editors and editorial board members from the top international league covering in depth the related topics. They will ensure the highest standards of quality for the published manuscripts and, at the same time, keep the process time as short as possible. We hope to bring best researches in the field of biomedical sciences that may serve as a guideline in health awareness, understanding the mechanisms and its management in future.   We definitely look forward to receiving your excellent studies to making PBMJ synonymous with high quality in the biomedical science domain.

Effects of Carbohydrate Binding Modules on Characteristics of Xylanases from Thermophilic Bacteria

Xylanases degrade the hemicellulosic component of plant biomass and find potential applications in poultry, paper, textile and biofuel industries. In this study, a novel, family GH10 enzyme, Xyn10B.CB3B2 from Acidothermus cellulolyticus 11B was characterized. This enzyme was found to be a trifunctional enzyme having endo xylanase, arabinofuranosidase and acetyl xylan esterase activities. Native xylanase, Xyn10B.CB3B2 had carbohydrate binding modules (CBM), CBM3 and CBM2 in tandem at the C-terminus. CBMs are protein domains that bind carbohydrate ligands and are found in carbohydrate active enzymes. Truncation of CBM2 was done to create Xyn10B.CB3 while CBM3 was fused to N-terminus of catalytic domain to form Xyn10B.B3C. Fusion of CBM2 at the C- and N-termini of the catalytic domain resulted in Xyn10B.CB2 and Xyn10B.B2C, respectively. In addition, only the catalytic domain (Xyn10B.C) was also characterized in this study. All of the enzyme variants were successfully expressed in soluble fraction of Escherichia coli cells and purified through binding with regenerated amorphous cellulose except Xyn10B.C that was obtained as inclusion bodies and purified by refolding. Activities of Xyn10B.CB3B2, Xyn10B.CB3, Xyn10B.B3C, Xyn10B.CB2, Xyn10B.B2C and Xyn10B.C on beechwood xylan were 118,305, 68,325, 65,825, 49,261, 44,518 and 40,368 U/μmol, respectively. Activities of Xyn10B.CB3B2, Xyn10B.CB3, Xyn10B.B3C, Xyn10B.CB2, Xyn10B.B2C and Xyn10B.C towards p nitorphenylarabinofuranoside were 9,042, 4,532, 4,026, 5,672, 5,137 and 4,340 U/μmol, respectively. Activities of Xyn10B.CB3B2, Xyn10B.CB3, Xyn10B.B3C, Xyn10B.CB2, Xyn10B.B2C and Xyn10B.C towards p-nitrophenylacetate were 15,545, 10,485, 8,856, 7,820, 7,571 and 7,342 U/μmol, respectively. All of the enzyme variants had optimum temperature 70 °C and optimum pH 6.0, under the vii assay conditions used. However, Xyn10B.C had optimum temperature and pH of 60 °C and 5.0-6.0, respectively. Binding assays revealed that all of the variants bound to insoluble oat spelt xylan and Avicel expect Xyn10B.C that did not bind to Avicel. Incubation of all enzyme variants with Mn2+ had negative impact on the activity of enzymes while other metal ions had no effect on the activity. Xyn10B.CB3B2 was stable up to 70 °C while Xyn10B.CB3, Xyn10B.B3C, Xyn10B.CB2 and Xyn10B.B2C were stable up to 60 °C. Xyn10B.C was stable only up to 50 °C as thermal unfolding was observed beyond these temperatures during CD spectroscopy analysis. All of the enzyme variants were highly active producing xylobiose and xylose as end products, as well as debranching the substrates by removing arabinose and acetyl side chains as observed by HPLC analysis of the lysates and arabinose/acetate assays. This study successfully elucidated the characteristcs of a novel trifunctional xylanase, Xyn10B. Due to its specific characteristics, Xyn10B.CB3B2 and its variants seem to be of importance for industrial applications. In another study, XynI from Caldicellulosiruptor saccharolyticus DSM 8903 was expressed in E. coli as 35.8 kDa protein in soluble form, but the expression level was rather low. MFOLD analysis of the sequence between the ribosomal binding site and the 5¢-end codons of the gene showed that the start codon AUG was trapped in the mRNA secondary structure. Cloning the gene using pET28a(+) increased expression to a level of 35% as compared to about 4% when expressed using pET22b(+). pET28a(+), having His-tag before the start codon, would prevent strong secondary structure formation thus allowing higher expression level. Activity of XynI was found to be 10, 5 and 6 U/mg on beechwood, birchwood and oat spelt xylan, respectively. Further studies are required to elucidate the reasons behind low activity through molecular modelling and docking analyses.