ABSTRACT
The e f f e c t s o f n o - t i l l a g e a g r i c u l t u r e upon s o i l p r o p e r t i e s have been e x t e n s i v e l y s t u d i e d ( P h i l l i p s and P h i l l i p s , 1984). I n t h e n o - t i l l system, a mulch o f p l a n t m a t e r i a l i s p r e s e n t a t t h e s o i l sur face. The amount o f s u r f a c e r e s i d u e v a r i e s as does i t s c o n d i t i o n ; f o r example, r e s i d u e s may be an a c t i v e l y growing
v e g e t a t i v e cover, o r t h e decaying r e s i d u e o f t h e p r e v i o u s crop. Management o f t h i s p l a n t r e s i d u e a f f e c t s t h e e x t e n t t o which i t i n f l u e n c e s p e s t i c i d e d i s s i p a t i o n . It i s obv ious t h i s s u r f a c e mulch w i l l i n t e r c e p t p a r t o f t h e p e s t i c i d e sp ray and t h u s i n t e r f e r e w i t h s u r f a c e coverage. T h i s i s one reason more p e s t i c i d e u s u a l l y i s r e q u i r e d t o c o n t r o l p e s t s i n n o - t i l l a g r i c u l t u r e . I f r a i n occurs soon a f t e r a p p l i c a t i o n , p a r t of t h e p e s t i c i d e w i l l be washed from t h e mulch o n t o t h e s o i l , b u t u s u a l l y a s i g n i f i c a n t amount remains i n t h e mulch. The d i s s i p a t i o n of t h i s p a r t w i l l be d i f f e r e n t f rom t h a t which reaches t h e s o i l .
