PRODUKSI DAN NILAI NUTRISI HIJAUAN JAGUNG MANIS (ZEA MAYSSACCHARATA) DENGAN PEMUPUKAN FOSFAT DAN INOKULASI MIKORIZA PADA KONDISI TANAH BERBEDA

(Production and Nutritive Value of Zea mays saccharata with Phosphorus Fertilization and Mycorrhiza Inoculation in the Different Soil Condition

Abstract

Rock phosphate  (RP) fertilizer   belongs  to slow available   source  of phosphorus  compared   to superphosphate   (SP),  and mycorrhiza  inoculation   maybe a promising   technique   to overcome the problem.   The symbiosis   between  mycorrhiza and Zea mays saccharaiaSturt   in  unsterilized soil   has been  less studied   compared  to sterilized   soil.    A greenhouse  experiment   was con• ducted on acid latosolic  soiland  low  phosphorus  availability.     The experimental    design was a factorial   2x2x3  in   3 replicates.     The  treatments  were  soil   sterilization    (unsterilized,    sterilized),  mycorrhiza   inoculation   (uninoculated,     inoculated)   and P fertilization   (RP-10,    RP-20, SP-36).   All pots received  fertilization   of 200 kg N/ha (6 g urea/pot),   150  kg K20/ha  (3.50 g KCl/pot)  and  150  kg P20/ha   of three kinds of P fertilizer  source  were RP-10 (21  g/pot),  RP- 20 (10.50    g/pot)  and SP-36  (6 g/pot).   The  latosolic   soil was sterilized   by autoclaf  at 121°c for  15  minutes.     Each  pot contain  8 kg dry  soil  and  inoculated   by 40 g soil   inoculum  of Glomus manihotis according   to the assigned   treatment  at the time  of planting.     Each  pot contain  2 plants  of Zea mays saccharata Sturt.   Zea mays was cut at ground  level  at 6 wekks after planting   and analyzed  for dry matter (DM),  N and P content.   Dry matter production,   N and P uptake  with SP fertilizer   were significantly    higher  compared  to RP (RP-IO,    RP-20)  on both  srreilized    soil  and  unsterilized    soil.   Dry  matter  production,   N and P uptake  with  SP fertilizer  on sterilized  soil  were significantly   higher  compared  to unsterilized   soil,   while  RP fertilizers  (RP-10,  RP-20)  were not significantly     different.    The  DM  production,   N and  P uptake of Zea mays were not significantly    affected  by the interaction.between     the treatments of mycorrhiza  inoculation,     P fertilization   and soil  sterilization.