Investigation of the effects of weeds and different control methods on walnut seedling height and stem diameter in the walnut nursery of Kahramanmaraş province

The walnut (Juglans regia L.), which plays an important role in human nutrition, is quite significant in terms of omega-3 fatty acids, antioxidants, polyphenols, copper, folic acid, phosphorus, manganese, vitamin B6, and vitamin E. In walnut nurseries, many weeds, diseases, and pests are encountered. One of the main problems in the nursery is the weeds. This study was carried out to determine the problem weed species, families and densities in the walnut (Juglans regia L.) nursery of Kahramanmaraş Faculty of Agriculture in the 2022-2023 period. At the same time, the effects of different weed control methods (hand hoe, pendimethalin 455g/l, glyphosate isopropylamine salt and mulch) on walnut sapling height and trunk diameter were investigated. As a result of the study, 66 weed species belonging to 20 different families were identified in the trial area. Of these weed species, 16 are monocotyledonous and 50 are dicotyledonous. According to the density scale, the weed species determined in the walnut experimental area were determined to be very dense with Elymus repens (L.) Gould 13.20, Sorghum halepense (L.) Pers. 12.69, Cynodon dactylon (L.) Pers. 11.58, Anagallis arvensis L. 10.70, and Digitaria sanguinalis (L.) Scop. 10.30 pieces/m². In this study, the mulching method reduced weed density by 98.07%, followed by hand hoeing with a reduction of 80.48%. The third method was post-emergence (glyphosate isopropylamin salt) herbicide treatment, which reduced weed density by 76.14%, and the fourth was pre-emergence (pendimethalin) herbicide treatment with a reduction of 74.10%. Among the weed control methods, the black plastic mulch method increased walnut seedling height by 633.33%, the hand hoeing method by 566.67%, the post-emergence herbicide treatment by 500.00%, and the pre-emergence herbicide treatment by 400.00%.