ECONOMIC THRESHOLD OF WILD MUSTARD (SINAPIS ARVENSIS L.) IN SAFFLOWER (CARTHAMUS TINCTORIUS L.)

Abstract

The use of intensive agricultural practices to obtain higher grain yield over several years in traditional oil-seed crops such as sunflower, canola, and maize eventually results in increased levels of some weeds in these crops. At this point, replacing these crops with different oil-seed crops such as safflower is a rational approach. However, weeds can also reduce safflower yield if they arc not controlled before reach to economic threshold. A 3-year field experiment was conducted to determine the economic losses from wild mustard (Sinapis arvensis L.), which is the main weed species, and the economic threshold level of wild mustard in safflower fields of Turkey in 2017-2019. Safflower yield decreased from 5% to 63% as the density of wild mustard increased from 0.5 to 16 plant m(-2), The economic threshold of wild mustard in safflower was calculated based on a rectangular non-linear hyperbolic regression model. The economic threshold was recorded 1.26, 1.06, and 1.32 plants m(-2) in 2017, 2018. and 2019, respectively, at a 91.25% control level by chlorsulfuron.