[Low risk] Annual ploughing [High risk] Continuous minimum tillage [Factor] 
Cultivation system
C r o p p i n g s y s t e m
C u l t i v a t i o n s y s t e m
W e e d c o n t r o l
H e r b i c i d e u s e
C o n t r o l i n p r e v i o u s y e a r s
W e e d i n f e s t a t i o n
R e s i s t a n c e i n v i c i n i t y