▁Category : 1 8 4 0 ▁death s ▁Category : 1 8 th - century ▁Indian ▁pain ters ▁Category : 1 9 th - century ▁Indian ▁pain ters ▁Category : P ain ters ▁from ▁Del hi <0x0A> </s> ▁Za ï ▁or ▁T assa ▁is ▁a ▁far ming ▁technique ▁to ▁dig ▁p its ▁( 2 0 - 3 0 ▁cm ▁long ▁and ▁deep ▁and ▁ 9 0 ▁cm ▁apart ) ▁in ▁the ▁soil ▁during ▁the ▁pr ese ason ▁to ▁catch ▁water ▁and ▁concent rate ▁comp ost . ▁The ▁technique ▁is ▁tradition ally ▁used ▁in ▁western ▁Sah el ▁( B urk ina ▁F aso , ▁Niger , ▁M ali ) ▁to ▁restore ▁de grad ed ▁dry lands ▁and ▁increase ▁soil ▁fert ility . ▁ ▁Za ï ▁holes ▁were ▁re int rodu ced ▁since ▁the ▁ 1 9 8 0 s ▁by ▁Y ac ou ba ▁S aw ad ogo , ▁a ▁far mer ▁from ▁Bur k ina ▁F aso , ▁who ▁introduced ▁the ▁innov ation ▁of ▁filling ▁them ▁with ▁man ure ▁and ▁comp ost ▁to ▁provide ▁plant ▁nut ri ents . ▁The ▁man ure ▁attract s ▁term ites , ▁whose ▁t unn els ▁help ▁further ▁break ▁up ▁the ▁soil . ▁He ▁also ▁slightly ▁increased ▁the ▁size ▁of ▁the ▁holes ▁over ▁the ▁traditional ▁models . ▁Za ï ▁holes ▁help ▁by ▁impro ving ▁the ▁yields ▁of ▁trees , ▁s org hum , ▁and ▁mil let ▁by ▁up ▁to ▁ 5 0 0 ▁percent . ▁ ▁As ▁an ▁alternative ▁to ▁the ▁za ï - te chni que ▁some