ABSTRACT
Conservat ion t i l l a g e systems m o d i f y a number o f chemical, b i o l o g i c a l and p h y s i c a l processes i n s o i l s r e l a t i v e t o more t r a d i t i o n a l t i l l a g e p r a c t i c e s t h a t d i s t u r b t h e s o i l and leave l i t t l e r e s i d u e cover. The acceptance o f c o n s e r v a t i o n t i l l a g e systems by producers i s f r e q u e n t l y determined by t h e r e l a t i v e economic advantage o f such systems. However, a number o f f a c t o r s and processes a r e i n v o l v e d t h a t may n o t be eva lua ted excep t i n terms o f f i n a l y i e l d . G i l l i a m and Hoyt (Chapter 13) p r e s e n t an e x c e l l e n t c o m p i l a t i o n o f c o n s e r v a t i o n t i l l a g e research which shou ld p rove t o be a v a l u a b l e r e f e r e n c e and s i g n i f i c a n t l y c o n t r i b u t e t o an express ion o f t h e dynamics o f n i t r o g e n (N) assoc ia ted w i t h t i l l a g e systems. L i t t l e more can be c o n t r i b u t e d i n terms o f a l i t e r a t u r e rev iew t h a t would f u r t h e r e l u c i d a t e t h e e f f e c t s o f t i l l a g e systems on N v o l a t i l i z a t i o n , d e n i t r i f i c a t i o n , m i n e r a l i z a t i o n , immob i l i za t ion , r u n o f f , and n i t r a t e leaching. The approach o f t h i s response paper w i l l be t o examine some o f t h e i n t e r a c t i o n s between t h e chemical. b i o l o g i c a l , and p h y s i c a l processes i n v o l v e d i n t i l l a g e systems i n an a t tempt t o s y s t e m a t i c a l l y e v a l u a t e t h e p o t e n t i a l e f f e c t on groundwater q u a l i t y .
