H. Cantarella et al., SOIL AND PLANT ANALYSES FOR LIME AND FERTILIZER RECOMMENDATIONS IN BRAZIL, Communications in soil science and plant analysis, 29(11-14), 1998, pp. 1691-1706
The fertilizer recommendation guidelines for over 160 crops for the St
ate of Sao Paulo, Brazil were updated in 1996 based on recent results
of research on soil and plant analysis, and crop responses. Recommenda
tions are based mainly on soil analysis and expected yield. Limestone
rates are calculated to raise soil base saturation as a percentage of
the cation exchange capacity (CEC) of the soil at pH 7.0, to levels wh
ich vary with crop species (i.e., to 50% for rice, coffee, and cassava
, 60% for sugar cane and soybeans, 70% for cotton and maize, and 80% f
or grapes and onions). In addition, exchangeable magnesium (Mg) conten
ts must reach a minimum level. Exchangeable subsoil aluminum (Al) and
calcium (Ca), and clay content are used to determine rates of gypsum a
s amendment of subsoil acidity. Fairly consistent data on soil phospho
rus (P) and potassium (K) calibration are available for Brazilian soil
s. Potassium rates are recommended based on values of soil exchangeabl
e K and, for P fertilization, ion exchange resin-extractable P is used
. For the later the ranges of interpretation of soil analysis are diff
erent for horticultural, annual, perennial, and forestry crops. No soi
l test is used for nitrogen (N) advisory purposes. For many crops, esp
ecially grains, N rates depend on the class of expected response to th
is element, defined as a function of previous management history, crop
rotation, texture etc. For some perennial crops N fertilizer rates ta
ke into account leaf N contents which were shown to correlate well wit
h N response for citrus, mango, and coffee. Soil analysis for micronut
rients, extracted with hot water [boron (B)] or DTPA-TEA [iron (Fe), c
opper (Cu), manganese (Mn), and zinc (Zn)] is also used as criterion f
or fertilizer recommendation although for most crops only B and/or Zn
are required.