How the Imprinting Machine Works During   the   past   two   decades,   the   general specifications    for    land    imprinters    were derived     from     the     principles     of     soil mechanics   and   the   hydro-biotic   function of    soil    imprints.    Mechanically,    imprints are    formed    through    downward    acting forces    applied    to    angular    steel    teeth. Troughs     or     indentations     are     formed through   soil   compression   and   shearing, whereas    adjacent    crests    or    ridges    are formed   by   an   embossing   (lifting)   process. Thus,   the   original   soil   surface   lies   in   a plane   about   midway   between   the   imprint trough   and   crest.   A   5-cm   (two   inch)   gap around   each   tooth   facilitates   these   two interacting    processes    with    minimal    soil disturbance and compaction. Imprints   are   25-cm   (10   inches)   long,   V- shaped     troughs     or     micro-watersheds which   funnel   resources   to   the   bottom   of the   vee   where   they   can   work   in   concert to      germinate      seeds      and      establish seedlings.      Each      micro-watershed      is about   30-cm   (one-foot)   square   in   surface area     and     can     hold     several     liters     of rainwater   on   level   ground.   This   is   enough water   to   germinate   and   establish   one   or more    seeds    or    seedlings.    Imprints    are staggered   and   separated   by   5-cm   (two inch)   wide   dikes   at   the   soil   surface   for safe      storage      of      rainwater      until      it infiltrates.     The     staggering     also     gives plants   more   room   to   develop   and   better exposure    to    vital    resources    including water   and   light.   Imprints   that   satisfy   the general    specifications    are    pictured    in figure   1.   Such   imprints   will   almost   always lead    to    successful    if    the    seed    mix    is adequate.     Such     imprints     are     stable enough      to      wait      several      years      for adequate rain to occur in the desert.

The Roller Blades Roller Categories To    assist    readers    who    wish    to    make their   own   imprinters,   specifications   are given     in     U.S.     Customary     (English) units.    The     structural     steel     used     to fabricate   imprinters   is   available   in   these units.   Conversion   factors   are   given   for the    convenience    of    those    working    in countries     where     steel     has     metric dimensions. Six     categories     of     imprinting     rollers result   from   various   combinations   of   2 angle   sizes   (6"x   6"   &   8"   x   8"),   2   angle shapes   (straight   and   bowlegged)   and two    cylindrical    core    diameters    (20"    & 24").   Category   specifications   are   given in   the   table   below.   Angular   teeth   are welded   radially   around   the   core   to   form 6   or   8   pointed   star   rings. Tooth   length   is 10    inches    and    the    spacing    between rings   is   about   2   inches.   Thus,   there   is one    star    ring    for    each    12    inches    of imprinting     roller     length.     Points     on adjacent    star    rings    are    staggered    to suppress    gully    formation.    The    radial basal   spacing   of   imprinting   teeth   is   also about   2   inches.   This   2   inch   gap   around the     base     of     each     tooth     improves penetration   into   the   soil   while   providing a    dam    between    adjacent    imprints    for safe     storage     of     collected     rain     or irrigation   water   until   it   infiltrates.   All   six categories    of    imprinting    rollers    make imprints   or   micro-watersheds   about   12 inches     square     in     size     and     shape. These      small      isolated      watersheds provide   excellent   control   of   infiltration and        the        microclimate,        greatly accelerating           the           revegetation processes.

The Tow Frame T he    front    and    rear    of    the    tow    frame    are square    tool    bars    which    permit    the    use    of commercial   tool   clamps   for   easy   attachment of   hitches   and   accessories   (Figures   1   &   2). Typically   the   draw   bar   tongue   is   removed   for trailer   hauling   to   reduce   the   width   of   the   load. Since   the   front   and   rear   of   the   tow   frame   are identical,   hitches   can   be   attached   to   either side   to   reverse   the   direction   of   roller   rotation. This     feature     nearly     doubles     the     life     of imprinting   teeth,   the   tips   of   which   concave sharpen on their leading edges  

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Figure 2 Tow     frame     and     imprint     rollers     with loading/unloading wheels attached.

• Frame   Shape   and   Size:   Rectangular   to   fit rollers 3,4,5,6,7,8,9 & 10 feet in length • Rear tool bar: (2 ¼-inch side) • Frame    Ends:    Clamped    to    tool    bars    with center bearing bracket • Roller   Axle:Full-length,   cold-rolled   steel,   2 ½-inch diameter • Axle   Bearings:   Pillow   block   type   with   cast steel    housing    and    double    tapered    roller bearings • for 2 ½-inch axle • Tool Attachments: • (1) Draw bar tongue for field operation • (2) Trailer loading and unloading wheels • (3) Three-point hitch (optional) • (4) Ripping Arms (optional)

Figure   1:   Imprinter   tow   frame   attached   to   a dozer   blade   to   form   a   steep-slope   imprinter. Tractor    hydraulics    force    imprinting    teeth    into the ground.

Well-formed   imprints   efficiently   establish vegetation    on    severely    degraded    land. Ripping   shanks   at   the   rear   of   the   tractor loosen hard soil spots enough to imprint.

The Nuts and Bolts of our Imprinting Machines