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Öğe Allelopathic Potential of Some Essential Oil Bearing Plant Extracts on Common Lambsquarters (Chenopodium album L.)(Revista Chimie Srl, 2016) Isik, Dogan; Mennan, Husrev; Cam, Mustafa; Tursun, Nihat; Arslan, MehmetAllelopathy can be regarded as a component of biological control in which plants are used to reduce development of other plants. Allelopathy refers to the direct or indirect chemical effects of one plant on the germination, growth or development of neighboring plants. The allelopathic effects of extracts of mint (Mentha piperita L.), thyme (Thymus vulgaris L.), rosemary (Rosmarinus officinalis L.), coriander (Coriandrum sativum L.) and sage (Salvia officinalis L.) on seed germination and some growth characteristics of common lambsquarters (Chenopodium album L.) were investigated. Aqueous extracts of aromatic plants at 0,1, 2.5, 5, 10 and 20 % concentrations were applied to determine their inhibition effects on seed germination; seedling shoot and root length of C. album seed under laboratory conditions. The extracts of tested plant species caused inhibitory effects on seed germination and seedling length of C. album. Allolapaticity increased progressively with the increasing extract concentration. The results showed that total germination inhibition of C. album depended on the extract concentration; ranged from %13 to 100. The maximum inhibition (100%) rate for germination was obtained from the highest extract concentration for all test species. Extracts of mint, thyme, rosemary, coriander and sage could be used as alternatives herbicides.Öğe Chemical Composition and Herbicidal Activities of Essential Oil from Aerial Parts of Origanum Hybrids Grown in Different Global Climate Scenarios on Seed Germination of Amaranthus palmeri(Taylor & Francis Ltd, 2021) Yasar, Ayse; Karaman, Yucel; Gokbulut, Incilay; Tursun, Ayse Ozlem; Tursun, Nihat; Uremis, Ilhan; Arslan, MehmetThe present study aimed to investigate the changes in the essential oil contents of some Origanum hybrids grown at different carbon dioxide (400 and 800 ppm) levels in a fully automated carbon dioxide greenhouse. The chemical composition of essential oils was analyzed gas chromatography/ mass spectrometry (GC/MS). It was found that, among the Origanum hybrids, there were differences between the essential oil contents of those grown under natural conditions and controlled greenhouse conditions. While an increase in carbon dioxide level significantly increased the thymol and carvacrol components, which are among important monoterpene components, of Origanum syriacum x O. onites and O. syriacum x O. vulgare hybrids, whereas it led to a decrease in O. syriacum x O. majorona hybrid. To determine the effects on germination of Amaranthus palmeri S. Watson seeds under laboratory conditions, the essential oils were used at 0.5, 1, 2, and 4 mu l/petri doses. The most effective doses of essential oils for preventing the germination of A. palmeri seed were found to be 2 and 4 mu l/petri. In preventing the germination of seeds, the most effective (100 %) application for all the essential oils was achieved with O. syriacum x O. onites hybrid grown at 800 ppm. These results show that the CO2 increases that may occur as a result of climate change in the next years may lead to changes in the content of essential oils in Origanum hybrids and may have the potential to be used as bio-herbicidal to prevent the germination of A palmeri.Öğe The Critical Period for Weed Control (CPWC) in Potato (Solanum tuberosum L.)(Univ Agr Sci & Veterinary Med Cluj-Napoca, 2015) Isik, Dogan; Akca, Adem; Kaya Altop, Emine; Tursun, Nihat; Mennan, HusrevAccurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used CO assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.Öğe The critical period for weed control in three corn (Zea mays L.) types(Elsevier Sci Ltd, 2016) Tursun, Nihat; Datta, Avishek; Sakinmaz, Mahmut Sami; Kantarci, Zekeriya; Knezevic, Stevan Z.; Chauhan, Bhagirath SinghKnowledge of the crop-weed competition period is vital for designing effective weed management strategies in crop production systems. Field studies were conducted at the Agricultural Research Institute, Kahramanmaras, Turkey in 2013 and 2014 to determine the critical period for weed control (CPWC) in three corn (Zea mays L.) types (field corn, popcorn, and sweet corn). A four parameter log-logistic model described the relationship between relative crop yield to both increasing duration of weed interference and length of weed-free periods. The relative yield of corn was influenced by duration of weed-infested or weed-free period, regardless of corn types. Increasing periods of weed interference significantly reduced corn yields in both years. In field corn, the CPWC ranged from 175 to 788 growing degree days (GDD) in 2013 which corresponded to V2-V12 growth stages, and 165-655 GDD (V1-V10 growth stages) in 2014 based on the 5% acceptable yield loss (AYL) level. In popcorn, the CPWC ranged from 92 to 615 GDD (VE-V10 growth stages) in 2013 and 110-678 GDD (V1-V10 growth stages) in 2014. In sweet corn, the CPWC ranged from 203 to 611 GDD in 2013 (V2-V10 growth stages) and 182-632 GDD (V2-V10 growth stages) in 2014. The practical implication of this study is that weed management should be initiated around V1 stage and maintained weed-free up to V12 stage in all corn types to prevent yield losses greater than 5%. These findings could help corn producers improve the cost effectiveness and efficacy of their weed management programs. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Detection and Molecular Characterization of two 'Candidatus Phytoplasma Trifolii' Isolates Infecting Peppers at the Same Ecological Niche(Friends Science Publ, 2017) Oksal, Hatice Digdem; Apak, Fulya Kaya; Oksal, Ercin; Tursun, Nihat; Sipahioglu, Hikmet MuratPepper (Capsicum annuum L.) cultivars exhibiting phytoplasma like symptoms including yellowing, flower sterility, necrosis, stunting and small leaves of lateral shoots were collected in Spring 2016 from Malatya province (Turkey). Leaf samples of the most common annual weeds and leafhoppers nearby symptomatic peppers were also sampled. Nested-PCR and virtual computer-simulated restriction fragment length polymorphism (virtual RFLP) methods have been implemented to ascertain and characterize the phytoplasma-associated disease. Using universal primer pairs in nested-PCR DNA fragments of approximately 1.2 kb were amplified from 3 pepper samples. None of the weed and leafhopper samples were reacted positive in PCR reactions. Next-generation sequencing (NGS) was used to sequence the amplified PCR fragments of two samples. The presence of 'Candidatus Phytoplasma trifolii' infections were confirmed by the analysis of 16S rDNA sequence and virtual-RFLP. Molecularly characterized isolates were designated as TR1 and TR2 (Acces. no: KY321932 and KY568694). Both isolates were identified as members of the clover proliferation phytoplasma group (subgroup 16SrVI-A) in pepper plants as strains of 'Ca. Phytoplasma trifolii'. Sequence alignment of the two 'Ca. Phytoplasma trifolii' isolates revealed a low level of genetic diversity. However, the restriction enzyme patterns of both isolates particularly in MseI profiles were differed from reference patterns of all previously established 'Ca. Phytoplasma trifolii' isolates in the world. Particularly, the TR2 isolate showed a point mutation comparing TR1 isolate and with reference strain (AY390261) of 'Ca. Phytoplasma trifolii'. This is the first report of 'Ca. Phytoplasma trifolii' isolates naturally infecting pepper plants from Turkey. (C) 2017 Friends Science PublishersÖğe Effects of Different Cover Crops on Soil Quality Parameters and Yield in an Apricot Orchard(Friends Science Publ, 2019) Demir, Zeynep; Tursun, Nihat; Isik, DoganCover crop treatments significantly increased yield in an apricot orchard according to the control. Effects of different cover crop treatments on some soil quality parameters and yield of a apricot orchard located in Turkey were investigated. For this purpose, Vicia villosa Roth. (VV), V. pannonica Crantz. (VP), a mixture of V. pannonica (70%) and Triticale (30%) (VPT) and Phacelia tanacetifolia Benth. (PT) were grown as winter cover crops, and Fagopyrum esculentum was grown as summer cover crop in the apricot orchard with clay soil. The experiment was done in a randomized complete block design with 4 replications including a plot mechanically cultivated (MC), herbicide treatment (HC) and bare control plot (BC). The soils were sampled from 0-20 cm and 20-40 cm depths in each plot for soil analyses. The cover crops enhanced soil quality parameters like organic matter (OM), total nitrogen (N), electrical conductivity (EC), basal soil respiration (BSR), structural stability index (SSI), aggregate stability (AS), saturated hydraulic conductivity (Ks), bulk density (BD), permanent wilting point (PWP), available water capacity (AWC) and field capacity (FC). The highest rises were in the treatment of the VV, diminishing the BD by 12.7% while raising the OM by 63.5%, Ks by 248.7%, AWC by 19.4% and SSI by 9.4% in the 0-20 cm soil depth. OM contents of cover crop treatments were ordered as; HC < BC < MC < PT < FE < VPT < VP < VV. The highest correlations among the soil parameters were obtained for the VV between OM and BD (-0.911**), BD and Ks (-0.906**), OM and Ks (0.989**). It was concluded based on current results that cover crops may be incorporated into cropping systems to improve soil quality. (C) 2019 Friends Science PublishersÖğe Effects of Different Practices on Seed Germination of Some Weeds Which is used as Medical(Kahramanmaras Sutcu Imam Univ Rektorlugu, 2015) Tursun, Ayse Ozlem; Dayisoylu, K. Sinan; Tursun, NihatStudy was conducted to determine the effect of temperature, scarification, the pH, light duration and salt concentration on Senecio vulgaris L., Taraxacum officinale L. and Tragopogo pratensis L. seeds. In the study results were determined the highest germination rate in 15 degrees C for S. vulgaris, 20 degrees C for T. officinale and 10 degrees C for T. pratensis, at each of the three seeds in 6 months in waiting period, 7 for pH, 16 hours light / 8 hours dark for S. vulgaris and T. officinale, 24 hours darkness for T. pratensis and in control for salt concentration in each of the three seeds. In case of the culture of these three weeds which used medical should be taken into the consideration to these conditions.Öğe Estimating Time of Weed Emergence in Cucumber (Cucumis sativus L.)(Türk Tarım - Gıda Bilim ve Teknoloji dergisi, 2015) Tursun, Nihat; Akinci, İrfan Ersin; Şahin, Mustafa; Uludağ, AhmetAbstract: İstatistiki modellerin geliştirilmesi için hıyar bitkisinde on bir önemli yabancı otun çıkış zamanın belirlenmesinde modellemeler yapılmıştır. Hıyar deneme arazisinde bulunan önemli yabancı otlar çıkış zamanlarına göre gruplara ayrılmıştır. Bu yabancı otlardan; Amaranthus retroflexus, Chenopodium album, Heliotropium europaeum, Polygonum aviculare ve Solanum nigrum erken, Convolvulus arvensis, Cyperus rotundus, Cynodon dactylon, Portulaca oleracea ve Sorghum halepense bütün vejetasyon boyunca ve Tribulus terrestris ise geç çimlenen yabancı ot türü olarak belirlenmiştir. Farklı doğrusal olmayan büyüme eğrileri (Chapman-Richard, Weibull, logistic, Gompertz ve cubic spline) farklı yabancı ot türleri ve yıllar için çıkış yüzdeleri verileri esas alınarak uyarlanmıştır. Cubic splin model birçok yabancı ot türü için en iyi model olarak saptanmıştır.Öğe Kayısı Bahçelerinde Yabancı Otlara Karşı Herbisitlere Alternatif Mücadele Yöntemlerinden Alevleme ve Örtücü Bitkilerin Kullanım Olanaklarının Araştırılması(2017) Tursun, Nihat; Işık, Doğan; Arslan, Selçuk; Demir, Zeynep; Karlıdağ, HüseyinBu çalışmanın genel amacı, kayısı bahçelerinde alevleme ve örtücü bitkilerin yabancı ot mücadelesinde kullanım olanaklarını araştırmaktır. Araştırma 2014-2016 yılları arasında yapılmıştır. Örtücü bitkilerin toprağın fiziksel, kimyasal ve biyolojik etkilerine olan etkileri tesadüf blokları deneme desenine göre belirlenmiştir. Kışlık örtücü bitki olarak Vicia villosa Roth. (Tüylü fiğ), Vicia pannonica Crantz (Macar fiği), Macar fiği ve tritikale karışımı (% 70 Macar fiği % 30 tritikale) Phacelia tanacetifolia Benth. (Arı otu); yazlık örtücü bitki olarak Fagopyrum esculentum Moench. (Karabuğday) kullanılmıştır. Örtücü bitkilerin yanı sıra yabancı otlu kontrol parseli, mekanik mücadele ve herbisitli mücadele parselleri olmak üzere 8 karakterli deneme deseni kurulmuştur. Yabancı otların yaş ve kuru ağırlıklarını azaltarak baskı altına alan en etkin yöntemlerin sırasıyla herbisit uygulaması, arı otu ve karabuğday olduğu bulunmuştur. Örtücü bitki uygulamaları toprak kalite indekslerini genellikle iyileştirmiştir. Organik madde, toplam azot, CO2 üretimi, elektriksel iletkenlik, tarla kapasitesi, agregat ve strüktür stabilite indeks değerleri kontrol uygulamasına göre önemli düzeyde artarken hacim ağırlığı, toprak reaksiyonu, değişebilir sodyum ve kalsiyum seviyelerinde genellikle azalma görülmüştür. Genel olarak, toprakların organik madde, toplam azot ve elektriksel iletkenlik özelliklerini artırmak ve fiziksel özelliklerini iyileştirmek için en uygun örtücü bitkilerin tek yıllık baklagillerden tüylü fiğ ve macar fiği olduğu bulunmuştur. Kayısı meyvesinin pomolojik analizlerinde en yüksek değerler Macar fiği + triticale uygulamasında elde edilmiştir. Bir alev makinesi geliştirilmiş ve 2015-2016 yıllarındaki uygulamalarında 11 çeşit yabancı otun doz-cevap eğrileri bulunmuştur. Geniş yapraklılarda uygulamadan 14 gün sonra %80 kontrol için 2-4 yaprak (Y), 6-8 Y ve 10-12 Y dönemlerinde sırasıyla ortalama 38, 56 ve 67 kg/ha, %90 kontrol hedefi için ise 43, 72 ve 75 kg/ha LPG dozu gereklidir. Dar yapraklı yabancı otlarda ise %80 yabancı ot kontrolü için sırasıyla 78, 104 ve 117 kg/ha, %90 için ise 110, 152 ve 175 kg/ha doz gerekli bulunmuştur. Alevlemede yakılan gaz maliyetinin geniş yapraklı yabancı otların erken büyüme döneminde herbisit maliyeti ile karşılaştırılabilir olduğu bulunmuştur.Öğe Managing weeds using crop competition in soybean [Glycine max (L.) CrossMark Melt](Elsevier Sci Ltd, 2017) Datta, Avishek; Ullah, Hayat; Tursun, Nihat; Pornprom, Tosapon; Knezevic, Stevan Z.; Chauhan, Bhagirath SinghSoybean (Glycine max (L) Merr.) is an important crop worldwide for both protein meal and vegetable oil. Soybean accounts for more than 50% of the global oilseed production. Weed infestation is a complex and regular threat to soybean production all over the world. To combat this threat, chemical, mechanical, and cultural methods are generally used. There has been a revived interest in weed suppression through improved crop competitiveness as an alternative aid in weed management. Different approaches could be utilized to increase crop competitiveness such as adjustment of row spacing, optimum seeding rate, and use of genotypes with high weed-competitive ability. During the past several decades, adoption of narrow row spacing has become increasingly popular among soybean growers primarily because of yield advantage and early canopy closure, which directly provides greater weed suppression. Adoption of narrow rows significantly reduces the density and biomass of late\-season emerging weeds and delays the critical time for weed removal compared with wide rows. An increase in seeding density/plant population also suppresses weeds by earlier canopy closure, especially when combined with narrow row spacing. Competitive abilities of different soybean cultivars against different weed species are not consistent. Interseeding cover crops after establishment of soybean also can be a viable option for weed suppression as long as cover crops do not compete with soybean, or act as weeds themselves. Integrated weed management is considered to be the most effective approach for long-term and sustainable management of weeds in soybean. The objective of this article is to provide an overview of currently known cropping practices for improving soybean competitiveness against weeds. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Mısır Varyetelerinde Yabancı Ot Kontrolü için Kritik Periyotların Belirlenmesi(Tarla Bitkileri Merkez Araştırma Enstitüsü Dergisi, 2016) Tursun, Nihat; Kantarcı, ZekeriyaÖz: Bu çalışma üç mısır varyetesinde (patlak mısır, at dişi mısır ve şeker mısır) 2013-2014 yıllarındaKahramanmaraş Doğu Akdeniz Geçit Kuşağı Tarımsal Araştırma İstasyonu'nda yabancı ot kontrolü için kritikperiyodun belirlenmesi amacıyla yapılmıştır. Çalışma sonucunda dört parametreli log-logistik model yardımıylayabancı otlu ve yabancı otsuz sürenin oransal mısır verimine olan etkisi hesaplanmıştır. Mısır varyetelerininoransal verimi yabancı otlu veya yabancı otsuz periyottan etkilenmiştir. Yabancı otlu süre arttıkça her iki yıldada mısır verimleri önemli oranda azalmıştır. Patlak mısırda yabancı otsuz kalması gereken süre kabul edilebilir%10 verim kaybında 2013 yılında 145-530 GDD (V1-V8 yapraklı dönem) olurken, 2014 yılında156-550 GDD(V1-V8 yapraklı dönem) olarak hesaplanmıştır. At dişi mısırda 2013 yılında 228-640 GDD (V2-V10 yapraklıdönem) belirlenirken, 2014'de ise 200-521 GDD (V2-V8 yapraklı dönem) saptanmıştır. Şeker mısırda isebu süreler 2013 yılında 258-520 GDD (V3-V8 yapraklı dönem) ve 2014 yılında ise 217-512 GDD (V2-V8yapraklı dönem) olduğu belirlenmiştir. Bu çalışma sonucunda %10 verim kaybı göz önündebulundurulduğunda mısır varyetelerine bakılmaksızın mısırın V2 yapraklı dönemden itibaren başlamak üzereV10 yapraklı döneme kadar yabancı otlarla mücadele edilmesi gerektiği sonucu ortaya çıkmaktadır.Öğe Nitrogen application influenced the critical period for weed control in cotton(Elsevier Sci Ltd, 2015) Tursun, Nihat; Datta, Avishek; Tuncel, Emine; Kantarci, Zekeriya; Knezevic, StevanThe critical knowledge of crop-weed competition period is important for designing weed management strategies in cropping systems. Field experiments were conducted in 2012 and 2013 growing seasons at the Agricultural Research Institute, Kahramanmaras, Turkey to determine the effect of three nitrogen (N) rates (0, 150 and 300 kg N ha(-1)) on the critical period for weed control (CPWC) in cotton. A four parameter log-logistic model was fit to the two sets of relating relative crop yield to data obtained from increasing durations of weed interference and lengths of weed-free period. In both the years and regardless of the N application rate, the relative yield of cotton decreased with increasing duration of weed-interference and increased with increasing duration of weed-free period. The application of N fertilizer delayed the beginning of the CPWC in cotton. At the 0 kg N ha(-1), the CPWC ranged from 44 to 537 GDD (growing degree days) (7-51 days after crop emergence [DAE]) in 2012 and 87-605 GDD (14 -57 DAE) in 2013 based on the 5% acceptable yield loss. At the 150 kg N ha(-1), the CPWC ranged from 124 to 597 GDD (18-56 DAE) in 2012 and 183-551 GDD (22-49 DAE) in 2013. Depending on the N application rate, weed-free conditions need to be established as early as one week after crop emergence and maintained as late as eight weeks after crop emergence to avoid more than 5% loss in cotton yield. These findings could help cotton producers improve the cost effectiveness and efficacy of their weed management programme under different N application rates. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Pamuk (Gossypium hirsitum L.)’da Yabancı Ot Kontrolü İçin Kritik Periyodun Belirlenmesinde Sıra Arası Mesafesi Etkilerinin Araştırılması(2016) Tursun, Nihat; Budak, Selvi; Kantarcı, ZekeriyaÖz: Arazi çalışmaları pamukta yabancı ot kontrolünde kritik periyodun belirlenmesinde üç farklı sıra arasımesafenin (50, 70 ve 90 cm) etkilerinin araştırılması için 2012-2013 yıllarında Kahramanmaraş Doğu AkdenizGeçit Kuşağı Tarımsal Araştırma İstasyonu'na ait arazide yapılmıştır. Dört parametreli log-logistik modelyabancı otlu ve yabancı otsuz periyodun kültür bitkisi veriminin oransal değerlerine göre dönüştürülmüştür.Pamuğun oransal verimi sıra arası mesafe göz önünde bulundurulmaksızın yabancı otlu yada yabancı otsuzdönemden etkilenmiştir. Yabancı otlu periyot arttıkça pamuk veriminde önemli derecede azalmalar olmuştur.Pamukta yabancı otların kontrolü için kritik periyot %2.5, %5 ve %10 kabul edilebilir ürün kayıpları temelindeoransal verim değerlerine göre hesaplanmıştır. 50 cm sıra arası mesafede, % 5 kabul edilebilir verim kaybındakritik periyot 2012 yılında 117-526 GGD olurken, 2013 yılında bu değer 124-508 GGD hesaplanmıştır. 70 cmde 2012 yılında 98-661 GGD elde edilirken, 2013 de ise 144-616 GGD ve 90 cm sıra arasında ise 2013yılında 80-771 GGD olurken, 2013 yılında 83-755 GGD arasında bulunmuştur. Bu bulgular farklı sıra arasımesafelerde yabancı ot kontrol programının faydasını ve fiyat etkinliğini geliştirmede pamuk üreticilerinefaydalı olabilecektirÖğe Role of Different Cover Crops on DTPA-Extractable Micronutrients in an Apricot Orchard(2019) Demir, Zeynep; Tursun, Nihat; Işık, DoğanAbstract: This study was conducted to compare the effect of different cover crop treatments on DTPAextractable micronutrients (Fe, Mn, Zn, Cu) and soil pH in an apricot orchard with clay texturelocated in Malatya province of Turkey. For this purpose, 5 different experimental groups (Viciavillosa Roth (VV), Vicia pannonica Crantz (VP), Vicia pannonica Crantz and Tritikale mixture(70% + 30%, respectively) (VPT), Phacelia tanacetifolia Benth (PT), Fagopyrum esculentumMoench (FE)) and 3 control groups (mechanically cultivated (MC), herbicide treatment (HC) andbare control plot (BC)) were used in the apricot orchards. The soils were sampled from 0–20 cm and20-40 cm depths in each plot for soil analyses. According to the obtained results, while cover croptreatments reduced pH values of soils according to the bare control, the cover crops increased theFe, Mn and Zn contents of soils in the 0-20 cm soil depth. The highest Ext-Fe, Mn and Zn contentswere obtained in the VV (14.83mg kg-1, 8.42 mg kg-1, 1.03 mg kg-1, respectively) at the 0-20 cm soildepth. As compared to bare control, highest percent increases in Fe, Mn and Zn contents weredetermined in the VV 27.73%, 31.69% and 37.54%, respectively. The greatest significant negativecorrelations in the VV treatment were observed between pH and Fe (-0.985**), between pH and Mn(-0.945**) and between pH and Zn (-0.764*). The greatest significant negative correlations in theVP treatment were observed between pH and Fe (-0.948**), between pH and Mn (-0.928**) andbetween pH and Zn (-0.722*). It was concluded based on current findings that cover crops,especially Vicia villosa Roth and Vicia pannonica Crantz could be incorporated into croppingsystems to improve micronutrients and to provide a sustainable soil management.Öğe Row spacing impacts the critical period for weed control in cotton (Gossypium hirsutum)(Springer, 2016) Tursun, Nihat; Datta, Avishek; Budak, Selvi; Kantarci, Zekeriya; Knezevic, Stevan Z.The knowledge on the critical crop-weed competition period is important for designing an efficient weed management program. Field studies were conducted in 2012 and 2013 at the Agricultural Research Institute, Kahramanmaras, Turkey to determine the effects of three row spacing (50, 70 and 90 cm) on the critical period for weed control (CPWC) in cotton. A four parameter logistic equation was fit to data relating relative crop yield to both increasing duration of weed interference and length of weed-free period. The relative yield of cotton was influenced by the duration of weed-infested or weed-free period, regardless of row spacing. In cotton grown at 50 cm row spacing, the CPWC ranged from 117-526 growing degree days (GDD) (V2-V11 growth stages) in 2012 and 124-508 GDD (V2-V10) in 2013 based on the 5% acceptable yield loss level. At 70 cm row spacing, the CPWC ranged from 98-661 GDD in 2012 (V2-V13) and 144-616 GDD (V2-V12) in 2013. At 90 cm row spacing, the CPWCranged from 80-771 GDD in 2012 (V1-V14) and 83-755 GDD (V1-V14) in 2013. In order to obtain a 95% weed-free yield, the weed management should start at 16 days after crop emergence (DAE) and continued until 52 DAE (V2-V11) for crops grown in 50 cm row spacing, 15 and 60 DAE (V2-V13) for 70 cm row spacing and 11 and 67 DAE (V1-V14) for crops grown in 90 cm row spacing. This suggests that cotton grown in narrow row spacing (50 cm) had greater competiveness against weeds compared with wider row spacing (70 and 90 cm). Cotton growers can benefit from these results by improving cost of weed control through better timing of weed management.Öğe Tıbbi Olarak Kullanılan Bazı Yabancı Ot Tohumlarının Çimlenmeleri Üzerine Farklı Uygulamaların Etkileri(2015) Tursun, Ayşe Özlem; Dayısoylu, K. Sinan; Tursun, NihatÇalışma; Senecio vulgaris L., Taraxacum officinale L. ve Tragopogon pratensis L. tohumlarının çimlenmesi üzerine sıcaklık, bekleme süresi, pH, ışık ve tuzun etkilerini belirlemek amacıyla yapılmıştır. Çalışma sonucunda S. vulgaris 15, T. officinale 20 ve T. pratensis ise 100C'de, bekleme süresinde her üç tohumda 6 ay, pH açısından pH 7, S. vulgaris ve T. officinale 16 saat aydınlık/ 8 saat karanlık, T. pratensis ise 24 saat karanlık, tuz istekleri bakımından ise kontrolde en fazla çimlenme oranına sahip oldukları tespit edilmiştirÖğe Use of Living, Mowed, and Soil-Incorporated Cover Crops for Weed Control in Apricot Orchards(Mdpi, 2018) Tursun, Nihat; Isik, Dogan; Demir, Zeynep; Jabran, KhawarApricot fruits provide important health, economic, and nutritional benefits. Weeds damage apricot production directly and host the pests that cause damages to apricot trees. However, very few studies are available on weed control in apricot orchards. This research work was aimed at evaluating five cover crops for weed suppression in apricot orchard. The effect of living, mowed, and soil-incorporated cover corps on weeds was recorded and compared with glyphosate application and mechanical weed control. The cover crops were Vicia villosa Roth., Vicia pannonica Crantz, Triticale + V. pannonica, Phacelia tanacetifolia Benth., and Fagopyrum esculentum Moench. Five major weed species in the experimental area were Amaranthus retroflexus L., Convolvulus arvensis L., Tribulus terrestris L., Sisymbrium officinale (L.) Scop., and Sorghum halepense (L.) Per. The highest biomass production was noted for Triticale + V. pannonica in 2015 and for P. tanacetifolia in 2016. Living cover crops were effective in decreasing the weed biomass compared with the control. Both mowing and soil incorporation of cover crops were effective in decreasing weed richness and density over control. Mowed or soil-incorporated cover crops were more effective than herbicide or mechanical weed control, while F. esculentum was the least effective cover crop for suppressing weeds in apricot orchard. The results of our studies implied that cover crops could be used for weed control in apricot, and their mowing or soil incorporation could enhance their efficacy.
