Agriculture Reference
In-Depth Information
0
100
200
400
600 mg N kg
-1
FIGURE 3.22
(
See color insert.
) Response of dry bean to nitrogen fertilization to a Brazilian Oxisol. Half
of the N was applied at sowing and the remaining half as topdressing at 35 days after sowing.
soil test has four components. These components are collecting the soil sample, extracting and
determining the available nutrients, interpreting the analytical results, and making the fertilizer
recommendations.
Traditionally, soil testing has involved the evaluation of nutrient deficiencies in soils; today, with
the increased emphasis on environment quality, soil tests are a logical tool to determine areas where
adequate or excess fertilization has taken place. In the soil testing program, the most important
point is to get a representative soil sample of an area to determine the fertility status of the soil
and make fertilizer recommendations. There is always a variation in the field in relation to soil
fertility. This is especially true when fertilizers are band or furrow applied. Hence, a large number
of soil samples are required at randomly selected points in a field. Fageria and Baligar (2005a)
600 mg N kg
-1
400
200
0
100
FIGURE 3.23
(
See color insert.
) Response of dry bean to nitrogen fertilization to a Brazilian Oxisol. Half
of the N was applied at sowing and the remaining half as topdressing at 35 days after sowing.
