02721nam a2200217 a 450000100080000000500110000800800410001910000180006024500660007826000210014430000090016549000310017452022040020565000090240965000170241865000090243565300150244465300170245965300170247665300100249317381461994-08-03       1973    bl uuuu      00u1 u    #d1 aHAUSER, G. F.  aThe calibration of soil tests for fertilizer recommendations.  aRoma : FAOc1973  a71p.  a(FAO. Soils Bulletin, 18).  aThe basic problems as discussed in this guide; Errors in soil test data and their prevention: error in the soil sample: duplicate soil sample versus repeated analysis; depth of soil sampling; errors in the laboratory; Comparison of chemical soil test procedures for selection of the most suitable analysis: introduction; procedure; repeated cropping of the potted soils; soil test methods correlating well with field data: nitrogen; phosphorus; potassium;  Growth factors and multivariate analysis: multivarieate analysis; growth factors influencing field; check list of growth factors: soil factors; climatic factors; farm management factors;  Field experiments for soil test calibrations: lay-out, design; management; observations during crop growth; harvest; Simultaneous calibration for two nutrients;  Graphical methods for improved soil test/yield response correlations; corrections for influencial growth factors: the principle; the graphical method; disturbing interactions and correlations between growth factors; successive corrections for various growth factors; curvilinear arrangements of points; the partition of graphs; intersection of regression lines and critical level; the logarithmic regression; hand-drawn regression curves; Improving soil test/crop response correlations; using nutrient uptake figures; percent yield versus absolute response; inconsistent data; The interpretation and use of soil test/crop response correlations for fertilizer recommendations; the interpretation graph; development of interpretation graphs from experimental data; basic fertilizer recomendations; site-specific adjustments of basic recommendations; follow-up field trials; the philosophy of soil test recommendations; Initiation of a soil testing service: general requirments: government attitude and placement of the soil testing service; technical personnel; technical approach to calibration problems; facilities for field experimentation; preparations in the laboratory; Start of field experimentation; Operational material and other requirements: request forms, sample boxes and soil test reports; crop information sheets; soil testing information sheets; assistance by extension service.  aSoil  aFertilizante  aSolo  aCalibracao  aFertilizacao  aRecomendacao  aTeste