Vegetables are a substantial part of our lives and possess great commercial and nutritional value. Weeds not only decrease vegetable yield but also reduce their quality. Non-chemical weed control is important both for the organic production of vegetables and achieving ecologically sustainable weed management. Estimates have shown that the yield of vegetables may be decreased by 45%–95% in the case of weed–vegetable competition. Non-chemical weed control in vegetables is desired for several reasons. For example, there are greater chances of contamination of vegetables by herbicide residue compared to cereals or pulse crops. Non-chemical weed control in vegetables is also needed due to environmental pollution, the evolution of herbicide resistance in weeds and a strong desire for organic vegetable cultivation. Although there are several ways to control weeds without the use of herbicides, cover crops are an attractive choice because these have a number of additional benefits (such as soil and water conservation) along with the provision of satisfactory and sustainable weed control. Several cover crops are available that may provide excellent weed control in vegetable production systems. Cover crops such as rye, vetch, or Brassicaceae plants can suppress weeds in rotations, including vegetables crops such as tomato, cabbage, or pumpkin. Growers should also consider the negative effects of using cover crops for weed control, such as the negative allelopathic effects of some cover crop residues on the main vegetable crop.

Bu araştırma hasat edilen buğday ürünü içerisine karışan yabancı ot tohumlarının belirlenmesi amacıyla Diyarbakır ilinde 2017 yılında yapılmıştır. Bu amaçla buğday tarımının yoğun yapıldığı 10 ilçedeki buğday ürünlerinden 100 örnek alınmıştır. Toplanan örnekler eleklerden (6-60 mesh) geçirilmek suretiyle içerisinde bulunan kaba ve cansız materyali alınmış, kalan kısımdaki yabancı ot tohumları ayrılmıştır. Yabancı ot tohumları binoküler mikroskop altında incelenerek tür teşhisleri gerçekleştirilmiştir. Diyarbakır ilinde hasat edilen buğday ürünü içerisine karışan yabancı ot tohumlarının oranı % 0.51 olduğu tespit edilmiştir. Tespit edilen bu yabancı ot tohumları 8 farklı familyadan 28 farklı yabancı ot türüdür. Bu yabancı otlardan en fazla karışımın 13 tür ile Poaceae familyasına ait olduğu görülmüştür. En yoğun bulunan yabancı otların Avena fatua ve Avena sterilis olduğu belirlenmiştir. Sonuç olarak, alınan 50.000 g buğday örneği içerisinde yabancı madde (yabancı ot tohumu+cansız maddeler) karışım miktarı ağırlık olarak 485.3 g ve karışım oranı ise % 1.0 olarak tespit edilmiştir. Yabancı ot tohum sayısı 633 adet ve tohum ağırlığı 10.96 gram bulunmuştur. Böylece 2016 yılı için Diyarbakır'da 2.638.909 da alanda 845.105 ton üretilen buğday ürününe hasatta yaklaşık 8.544 ton yabancı ot tohumu ve yabancı madde karıştığı söylenebilir. Buğday içerisinde bulunan yabancı maddenin niteliği ve niceliği buğdayın kalitesini etkileyen kriterlerden birisidir. Yabancı otların öğütme değeri olmadığından bunların buğday üretimi esnasında etkili bir şekilde kontrol edilmesi veya öğütme öncesi ayıklanması gıda ve halk sağlığı bakımından önemlidir.

The weed species in the common barley (Hordeum vulgare L.) fields in the Diyarbakir were observed with this study. For this purpose, 50 quadrats of 1m by 1m (1 m -2 ) were randomly placed and examined at each study site. In every set of the quadrat, frequency and density were observed throughout the cropping season of 2015-2016. During the course of field study 72 weed species belonging to 21 families, 13 grasses, 59 broadleaves were recorded. The common families were Asteraceae and Poaceae in the common barley fields. The encounter frequency of weeds was determined by observing 80% wild mustard (Sinapis arvensis L., 80%), animated oat (Avena sterilis L., 63%), common wild oat (Avena fatua L., 54%), corn buttercup (Ranunculus arvensis L., 54%), corn poppy (Papaver rhoeas L., 52%), creeping thistle (Cirsium arvense (L.) Scop., 51%), volunteer lentils (Lens culinaris Medik., 51%). Wild mustard, which had the highest frequency was also the densest weed species (5.18 plant m -2 ), and other species such as animated oat (4.33 plant m -2 ), creeping thistle (1.77 plant m -2 ), common wild oat (1.72 plant m -2 ), corn buttercup (1.47 plant m -2 ), cleavers (1.38 plant m -2 ), corn poppy (1.22 plant m -2 ), volunteer lentils (1.07 plant m -2 ) were important species at all the observed fields. It was observed that the great infestation was shown by broadleaf weeds due to the lack of effective weed control in the barley areas.

A questionnaire consisting of 20 questions about weed, herbicide, tillage and crop rotation was applied to 100 lentil farmers to determine the current state of a weed problem in lentil fields in 2016. Common weeds were determined charlock mustard (Sinapis arvensis L., 36%), devil-on-all-sides (Ranunculus arvensis L., 16%), cleavers (Galium aparine L., 11%), makhobeli (Cephalaria syriaca L., 8%), and knapweed (Centaurea depressa L., 8%), respectively. The majority of participants used aclonifen (89%) as a post-emergence to control broadleaf, besides, clethodim (26%), haloxyfop-methylester (17%), tepraloxydim (16%), quizalofop p-ethyl (15%), and fluazifop p-butyl (6%) for grass, respectively, and as a total herbicide glyphosate (4%) as well. But, respondents (66%) stated that lentils had crop injury from aclonifen. Growers took into account the price (43%), herbicides (38%), weeds (10%) and crop rotation (9%) to choose herbicides. Managing weeds with hand-picked (76%) were common in areas that did not use herbicides. Preventive measures were used such as crop rotation (61%), late sowing (10%), and deep tillage (4%), furthermore, farmers planted wheat (91%) and barley (9%) as a preceding crop. In this study, dissatisfaction was determined by the efficacy and selectivity of aclonifen which is registered herbicide on lentils in Turkey. Lentils have a short stature, slow early-season growth rate, and open-canopy growth habit, which make them poor competitors with broadleaf weeds. So weed management in the early period such as pre-planting, pre-emergence or early post-emergence herbicides, and IMI herbicide-tolerant lentil varieties (Clearfield) have been investigated.

Determination of weed species in wheat fields of Diyarbakir province This study was carried out as a survey to determine weed species, their observation frequencies and densities in wheat fields of seventeen districts of Diyarbakır province during 2016-2017. For this purpose, field observations were made in total 106 location and the weed species and their frequency and densities were recorded. As a result of the observations; 107 weed species belonging to 26 families, 1 seedlees, 19 monocotyledons, 87 dicotyledons were detected. Families of Asteraceae, Poaceae, Brassicaceae, Apiaceae and Fabaceae, which are the most dominant in the fields and containing 2/3 of all species have been found in survey. Avena fatua L., Sinapis arvensis L., Ranunculus arvensis L., Galium aparine L. ve Cirsium arvense (L.) Scop. were identified as the most common species respectively, and their ratios are 87, 78, 72, 62 and 58%. According to density Avena fatua L. with 9.73 plant m-2 has received the first place. It was followed by Sinapis arvensis L., Galium aparine L., Papaver rhoeas L., Cirsium arvense (L.) Scop. with the numbers of 8.83, 5.94, 2.62 ve 2.45 plant m-2 respectively. Despite the decrease in frequency and density of weeds compared to past years, the results obtained have shown that effective weed management is not exercised.