▁be ▁made ▁from ▁plant ▁material ▁with ▁a ▁suitable ▁mo ist ure ▁content : ▁about ▁ 5 0 % ▁to ▁ 6 0 % ▁depending ▁on ▁the ▁means ▁of ▁storage , ▁the ▁degree ▁of ▁compression , ▁and ▁the ▁amount ▁of ▁water ▁that ▁will ▁be ▁lost ▁in ▁storage , ▁but ▁not ▁exceed ing ▁ 7 5 %. ▁We ather ▁during ▁har vest ▁need ▁not ▁be ▁as ▁fair ▁and ▁dry ▁as ▁when ▁har vest ing ▁for ▁dry ing . ▁For ▁corn , ▁har vest ▁begins ▁when ▁the ▁whole - plant ▁mo ist ure ▁is ▁at ▁a ▁suitable ▁level , ▁ide ally ▁a ▁few ▁days ▁before ▁it ▁is ▁ri pe . ▁For ▁past ure - type ▁cro ps , ▁the ▁grass ▁is ▁m own ▁and ▁allowed ▁to ▁w ilt ▁for ▁a ▁day ▁or ▁so ▁until ▁the ▁mo ist ure ▁content ▁dro ps ▁to ▁a ▁suitable ▁level . ▁Ide ally ▁the ▁c rop ▁is ▁m owed ▁when ▁in ▁full ▁flower , ▁and ▁depos ited ▁in ▁the ▁sil o ▁on ▁the ▁day ▁of ▁its ▁cutting . ▁ ▁After ▁har vest ing , ▁cro ps ▁are ▁sh red ded ▁to ▁pieces ▁about ▁ ▁long . ▁The ▁material ▁is ▁spread ▁in ▁uniform ▁layers ▁over ▁the ▁floor ▁of ▁the ▁sil o , ▁and ▁closely ▁pack ed . ▁When ▁the ▁sil o ▁is ▁filled ▁or ▁the ▁stack ▁built , ▁a ▁layer ▁of ▁st raw ▁or ▁some ▁other ▁dry ▁por ous ▁subst ance ▁may ▁be ▁spread ▁over ▁the ▁surface . ▁In ▁the ▁sil o ▁the ▁pressure ▁of ▁the ▁material , ▁when ▁ch aff ed