of fertilization standard are applied when the analyzed conditions are higher than the criteria.
A total of 30–40 kg MgO ha
−1 of magnesium is applied
when the analyzed soil conditions (exchangeable magnesium
extracted by pH 7 ammonium acetate) are within the range
of 250–450 mg MgO kg
−1 . A total of 1.3–1.5 folds of
magnesium fertilizer are applied when the soil concentration
of exchangeable magnesium is lower than 250 mg MgO
kg
−1 , and no magnesium fertilizer is applied when the
concentration is higher than 450 mg MgO kg
−1 .
For calcium fertilizer application, the soil pH criterion
(5.5–6.5 as pH(H 2 O), soil:water = 1:2.5) is regarded as more
important than the concentration of exchangeable calcium;
that is, calcium application is recommended to keep soil pH
within the range 5.5–6.5.
(3) Fertilization with allowance for the application of
organic matter
Application of organic matter is indispensable as a countermeasure against the degradation of soil fertility, and the
application of 10 t ha
−1 of manure every year is recommended in Hokkaido.
The use of fertilizers needs to be reduced, with allowance
for the application of nutrient elements provided by applied
organic matter. For example, 1 kg of N fertilizer can be
reduced per 1 Mg of manure applied, because approximately
20% of N in manure could be taken up by plants, and the
total amount of N per 1 Mg of manure is estimated as
approximately 5 kg. When applying manure consecutively
every year, the available N from manure is thought to
increase due to the accumulation effect. When applying
manure for 5–10 consecutive years, the amount of nitrogen
fertilizer can be reduced by 2 kg of N fertilizer per 1 Mg of
manure, and when applying manure over 10 consecutive
years, the amount of fertilizer can be reduced by 3 kg of N
fertilizer per 1 Mg of manure applied.
(4) Trace element fertilization
In Hokkaido, a deficiency of zinc (Zn) and copper (Cu) is
frequently observed in typical commercial agricultural fields.
Zinc deficiency tends to occur when growing beans and
corn (Fig. 5.2). A basic precaution against zinc deficiency is
the application of zinc fertilizer to the soil. The criterion
concentration of soil available zinc is set as 2–40 mg kg
−1 ,
and 50 kg ha
−1 of zinc sulfate (7-hydrate) is recommended
to be applied to soil when a deficiency is observed, that is,
when the concentration of soil available zinc is lower than
the criterion.
Copper deficiency tends to occur in wheat (Fig. 5.3). The
criterion concentration of soil available copper differs for
different soil humus contents: The criterion is 0.7 mg kg
−1
when soil humus content is less than 50 g kg
−1 ; 0.5 mg
kg
−1 when soil humus content is in the range of 50–
100 g kg
−1 ; and 0.3 mg kg
−1 when soil humus content is
more than 100 g kg
−1 . Between 20 and 40 kg ha
−1 of copper sulfate (pentahydrate) is recommended to be applied to
soil when a deficiency is observed, that is, when the concentration of soil available copper is lower than the criterion.
Fig. 5.2 Typical symptom of zinc deficiency of soybean (left) and azuki bean (right). Figure supplied by Nobuhiko Fueki
144
T. Nakatsuji et al.
A total of 30–40 kg MgO ha
−1 of magnesium is applied
when the analyzed soil conditions (exchangeable magnesium
extracted by pH 7 ammonium acetate) are within the range
of 250–450 mg MgO kg
−1 . A total of 1.3–1.5 folds of
magnesium fertilizer are applied when the soil concentration
of exchangeable magnesium is lower than 250 mg MgO
kg
−1 , and no magnesium fertilizer is applied when the
concentration is higher than 450 mg MgO kg
−1 .
For calcium fertilizer application, the soil pH criterion
(5.5–6.5 as pH(H 2 O), soil:water = 1:2.5) is regarded as more
important than the concentration of exchangeable calcium;
that is, calcium application is recommended to keep soil pH
within the range 5.5–6.5.
(3) Fertilization with allowance for the application of
organic matter
Application of organic matter is indispensable as a countermeasure against the degradation of soil fertility, and the
application of 10 t ha
−1 of manure every year is recommended in Hokkaido.
The use of fertilizers needs to be reduced, with allowance
for the application of nutrient elements provided by applied
organic matter. For example, 1 kg of N fertilizer can be
reduced per 1 Mg of manure applied, because approximately
20% of N in manure could be taken up by plants, and the
total amount of N per 1 Mg of manure is estimated as
approximately 5 kg. When applying manure consecutively
every year, the available N from manure is thought to
increase due to the accumulation effect. When applying
manure for 5–10 consecutive years, the amount of nitrogen
fertilizer can be reduced by 2 kg of N fertilizer per 1 Mg of
manure, and when applying manure over 10 consecutive
years, the amount of fertilizer can be reduced by 3 kg of N
fertilizer per 1 Mg of manure applied.
(4) Trace element fertilization
In Hokkaido, a deficiency of zinc (Zn) and copper (Cu) is
frequently observed in typical commercial agricultural fields.
Zinc deficiency tends to occur when growing beans and
corn (Fig. 5.2). A basic precaution against zinc deficiency is
the application of zinc fertilizer to the soil. The criterion
concentration of soil available zinc is set as 2–40 mg kg
−1 ,
and 50 kg ha
−1 of zinc sulfate (7-hydrate) is recommended
to be applied to soil when a deficiency is observed, that is,
when the concentration of soil available zinc is lower than
the criterion.
Copper deficiency tends to occur in wheat (Fig. 5.3). The
criterion concentration of soil available copper differs for
different soil humus contents: The criterion is 0.7 mg kg
−1
when soil humus content is less than 50 g kg
−1 ; 0.5 mg
kg
−1 when soil humus content is in the range of 50–
100 g kg
−1 ; and 0.3 mg kg
−1 when soil humus content is
more than 100 g kg
−1 . Between 20 and 40 kg ha
−1 of copper sulfate (pentahydrate) is recommended to be applied to
soil when a deficiency is observed, that is, when the concentration of soil available copper is lower than the criterion.
Fig. 5.2 Typical symptom of zinc deficiency of soybean (left) and azuki bean (right). Figure supplied by Nobuhiko Fueki
144
T. Nakatsuji et al.