02500naa a2200361 a 450000100080000000500110000800800410001910000170006024500980007726000090017530000210018449000080020552015410021365000150175465000220176965000150179165000090180665000150181565000290183065000160185965000090187565000090188465300080189365300170190165300180191865300120193665300080194870000170195670000130197370000200198670000170200677301150202314516842004-10-26       1989    bl uuuu     u00u1 u    #d1 aBOUNIOLS, A.  aModelling soybeans nitrogen nutrition in various soil depths, irrigations and fertilizations.  c1989  ap.2163-2170. t.5  vt.5  aAn attempt was made to adapt the multispecies E.P.I.C. model (created by USDA-ARS team at Temple, Texas) to simulate yield and N-nutrition of soybeans grown under various field conditions. A subroutine of soybean nitrogen fixation and plant uptake of mineral nitrogen was incorporated into the previous model in order to account of nodule growth and duration of activity as well as limitations in symbiotic activity by drought and N soil residues. The simulation shows the marked effect of soil depth on yield response to water constraints. The discrepancy between 0.6 to 1.60m deep soil may vary from 0.76 to 1.5 t.ha-1. Aboveground plant N content also increases according to soil depth. The model predicts that water supply on a 1 m deep soil may produce a yield grain of 0.8 to 1.1 t.ha-1 depending on weather demand. Deficiencies in nitrogen nutrition are specially apparent under non-irrigated conditions. Simulation of quantities of symbiotically-N fixed versus N-uptake demonstrates that, in all soil depth, irrigation increases the amount of fixed N. A nitrogen supply at the beginning of growth cycle may reduce N fixation. On the other hand, late fertilization (via N-fertilizating irrigations) during reproductive development (R3 or R5) enhances N-absorption from soil reserves and fertilizers with a moderated effect on nodule function. So, in that case, the two processes of N-nutrition occur simultaneously and do not appear to be antagonist. For the different cultural conditions, the simulations of yield, N content ...  airrigation  anitrogen fixation  aphysiology  asoil  aFisiologia  aFixação de Nitrogênio  aIrrigação  aSoja  aSolo  aEUA  aFertilizacao  aFertilization  aSoybean  aUSA1 aBLANCHET, R.1 aBONA, S.1 aCABELGUENNE, M.1 aJONES, C. A.  tIn: CONFERENCIA MUNDIAL DE INVESTIGACION EN SOJA, 4., 1989, Buenos Aires. Actas... Buenos Aires: AASOJA, 1989.