▁from ▁the ▁bottom ▁in ▁winter . ▁This ▁requires ▁considerable ▁effort ▁to ▁compress ▁the ▁stack ▁in ▁the ▁sil o ▁to ▁c ure ▁it ▁properly . ▁Again , ▁the ▁pit ▁is ▁covered ▁with ▁pl astic ▁sheet ▁and ▁we ighed ▁down ▁with ▁t ires . ▁ ▁In ▁an ▁alternative ▁method , ▁the ▁cut ▁veget ation ▁is ▁b aled , ▁making ▁bal age ▁( N orth ▁America ) ▁or ▁sil age ▁b ales ▁( UK ). ▁ ▁The ▁grass ▁or ▁other ▁for age ▁is ▁cut ▁and ▁partly ▁d ried ▁until ▁it ▁contains ▁ 3 0 – 4 0 % ▁mo ist ure ▁( m uch ▁d rier ▁than ▁bulk ▁sil age , ▁but ▁too ▁d amp ▁to ▁be ▁stored ▁as ▁dry ▁hay ). ▁ ▁It ▁is ▁then ▁made ▁into ▁large ▁b ales ▁which ▁are ▁wrapped ▁tight ly ▁in ▁pl astic ▁to ▁exclude ▁air . ▁ ▁The ▁pl astic ▁may ▁wrap ▁the ▁whole ▁of ▁each ▁cyl ind rical ▁or ▁cub oid ▁b ale , ▁or ▁be ▁wrapped ▁around ▁only ▁the ▁cur ved ▁sides ▁of ▁a ▁cyl ind rical ▁b ale , ▁leaving ▁the ▁ends ▁un cover ed . ▁ ▁In ▁this ▁case , ▁the ▁b ales ▁are ▁placed ▁tight ly ▁end ▁to ▁end ▁on ▁the ▁ground , ▁making ▁a ▁long ▁continuous ▁" s aus age " ▁of ▁sil age , ▁often ▁at ▁the ▁side ▁of ▁a ▁field . ▁ ▁The ▁wrapping ▁may ▁be ▁performed ▁by ▁a ▁b ale ▁wrapper , ▁while ▁the ▁b aled ▁sil age ▁is ▁handled ▁using ▁a ▁b ale ▁handler ▁or ▁a ▁front - loader