ABSTRACT
If th e la n d w ill b e p lo u g h e d , p a rtic u la rly b y sm a ll tra c to r, o r if ra in fall is v e ry h e a v y a n d lo n g la stin g (3) is im p o rta n t.
In o th e r ca se s su ch as w h e re th e slo p e is ste e p a n d th e ra in h eav y , o r th e soil is v e ry u n sta b le (4) w ill b e th e m o s t im p o r ta n t factor.
