Biotech Studies 2016, Vol 25, Num, 2     (Pages: 100-105)

The Effects of Row Spacing on Determination of Critical Period for Weed Control in Cotton (Gossypium hirsitum L.)

Nihat TURSUN 1 ,Selvi BUDAK 2 ,Zekeriya KANTARCI 3

1 İnönü Üniversitesi, Ziraat Fakültesi, Bitki Koruma Bölümü, Malatya
2 Kahramanmaraş Sütçü İmam Üniversitesi, Fen Bilimleri Enstitüsü, Kahramanmaraş
3 Doğu Akdeniz Geçit Kuşağı Tarımsal Araştırma İstasyonu, Kahramanmaraş
DOI : 10.21566/tarbitderg.281866 - Field studies were conducted in 2012 and 2013 in Agricultural Research Institute Kahramanmaras, Turkey to determine the effects of three row spacings (50, 70 and 90 cm) on the critical time for weed removal (CTWR) in cotton. A four parameter logistic equation was fit to data relating relative crop yield to increasing duration of weed presence. The CPWC in cotton based on a 2.5%, 5% and 10% acceptable yield loss (AYL) was calculated to relative yield data. The beginning of the critical period in row spacing in cotton calculated from the above equations became earlier as the predetermined acceptable yield loss level (AYL) decreased from 10% to 2.5%. At the 50 cm row spacing, the CPWC ranged from 117–526 GDD (V2–V11 growth stages) in 2012 and 124–508 GDD (V2–V10 growth stages) in 2013 based on the 5% acceptable yield loss (AYL) level. At the 70 cm row spacing, the CPWC ranged from 98–661 GDD in 2012 (V2–V13 growth stages) and 144–616 GDD (V2–V12 growth stages) in 2013. These findings could help cotton producers improve the cost effectiveness and efficacy of their weed management programme under different row spacing management practices. Keywords : Critical duration of weed interference, critical weed-free period, timing of weed removal, cotton crop competition, weed interference