5.8.2 Soil Management
(1) Labeling the clean agriculture
“Clean agriculture” is a mode of environmental conservation
agriculture, which was first advocated in Hokkaido, in 1991.
It involves producing safe, high-quality agricultural products
in harmony with the environment, using methods such as
soil preparation by the application of organic materials and
cultivation using minimal amounts of chemical fertilizers
and chemically synthesized pesticides.
In 2000, the Hokkaido Clean Agriculture Promotion
Committee established the “Certification Mark System for
Northern Clean Agricultural Products” through which the
YES! Clean mark (Fig. 5.13) is displayed on products that
meet predetermined fertilizer application and pest control
standards, present cultivation information and have been
promoting the spread of the system and the development of
registered production groups.
(2) Fertilizer application standards for certification
system
The system not only obligates soil diagnosis and sets the
upper limit for the amount of chemical fertilizer application,
but also sets the upper limit for the total amount of nitrogen
application, which is the total amount of nitrogen components supplied from fertilizers, including compost and
organic fertilizers, corresponding to the soil nitrogen fertility
level (Table 5.19). Additionally, for the application of
organic materials such as compost, the lower limit for the
application amount of organic material including compost
and the upper limit for the application amount of compost
are set to ensure the maintenance and improvement of soil
fertility and the mitigation of the nitrogen load on the
environment. Details of soil diagnosis and fertilizer application standards are presented below.
For fields registered in the Certification Mark System for
Northern Clean Agricultural Products, it is necessary to
conduct soil diagnosis using analytical parameters predetermined for different kinds of crops. The nitrogen fertility of
respective fields is evaluated using the diagnosis results. The
upper limit of total nitrogen application described below is
determined based on this nitrogen fertility. “Wet incubation
nitrogen,” “autoclave-extractable nitrogen,” and “raw soil
incubation nitrogen,” which are analytical parameters used
for paddy rice, field crops, and vegetables grown outdoors,
show stable values for a long period. Therefore, a value from
analysis in the last 3-year period is useful. Performing soil
diagnosis every 3 years is sufficient after registration. For
“nitrate nitrogen”, which is an analytical parameter used for
greenhouse vegetables, an analysis value within the last
1-year period must be used. Soil diagnosis is conducted
every year after registration.
Total nitrogen application consists of the integrated
amount of nitrogen component derived from organic materials including compost, chemical fertilizers, and organic
fertilizers used in the period relevant to each crop. The
standard fertilizer application corresponding to the soil nitrogen fertility level is fundamentally applicable to the upper
limit of total nitrogen application. However, the standard
fertilizer application might vary for some crops by zone
category or soil category. The maximum value of the standard fertilizer application was used for such crops.
The upper limit of chemical fertilizer application is
determined using the remaining nitrogen amount obtained
by subtracting the nitrogen supply when the lower limit of
organic matter including compost is applied from the upper
limit of the total nitrogen application. However, fertility
enhancement by the application of organic matter including
compost is required in a field with soil nitrogen fertility
classified as “low.” Therefore, the value of “middle” soil
nitrogen fertility was applied for the upper limit of chemical
fertilizer application.
The lower limit of application of organic materials
including compost represents the amount of organic material
which must be applied annually to fields using the “amount
of compost application to maintain soil fertility” shown in
the Hokkaido fertilizer application guidelines. The value is
10 Mg ha
−1 for paddy rice and field crops, 20 Mg ha
−1 for
vegetables, flowers, and ornamental plants grown outdoors
and fruit trees, and 40 Mg ha
−1 for vegetables, flowers, and
ornamental plants grown in greenhouses.
However, for cases in which only a small amount of
compost is available, or when quality benefits are achieved
in crops more easily without compost application, the concept described below is used for the application of organic
materials including compost: Organic matter that can supply
nitrogen component or dry weight equivalent to compost is
useful as “organics equivalent to compost.” Organic materials such as fish meal and fermented chicken manure can be
converted into compost with an equivalent nitrogen component (Table 5.20). Till in, green manure can also be
converted into compost based on dry weight. Therefore, the
standard can be met using by applying appropriate organic
material instead of using compost.
Nitrogen mineralization occurs in compost during periods
when no crop is grown. It is therefore feared that the
application of large quantities of compost might become a
source of environmental pollution such as groundwater
contamination. For that reason, an upper limit of compost
application amount is set for compost containing a high
percentage of nitrogen-rich cattle manure, such as cattle
manure/straw compost and cattle manure/bedding compost.
170
T. Nakatsuji et al.
(1) Labeling the clean agriculture
“Clean agriculture” is a mode of environmental conservation
agriculture, which was first advocated in Hokkaido, in 1991.
It involves producing safe, high-quality agricultural products
in harmony with the environment, using methods such as
soil preparation by the application of organic materials and
cultivation using minimal amounts of chemical fertilizers
and chemically synthesized pesticides.
In 2000, the Hokkaido Clean Agriculture Promotion
Committee established the “Certification Mark System for
Northern Clean Agricultural Products” through which the
YES! Clean mark (Fig. 5.13) is displayed on products that
meet predetermined fertilizer application and pest control
standards, present cultivation information and have been
promoting the spread of the system and the development of
registered production groups.
(2) Fertilizer application standards for certification
system
The system not only obligates soil diagnosis and sets the
upper limit for the amount of chemical fertilizer application,
but also sets the upper limit for the total amount of nitrogen
application, which is the total amount of nitrogen components supplied from fertilizers, including compost and
organic fertilizers, corresponding to the soil nitrogen fertility
level (Table 5.19). Additionally, for the application of
organic materials such as compost, the lower limit for the
application amount of organic material including compost
and the upper limit for the application amount of compost
are set to ensure the maintenance and improvement of soil
fertility and the mitigation of the nitrogen load on the
environment. Details of soil diagnosis and fertilizer application standards are presented below.
For fields registered in the Certification Mark System for
Northern Clean Agricultural Products, it is necessary to
conduct soil diagnosis using analytical parameters predetermined for different kinds of crops. The nitrogen fertility of
respective fields is evaluated using the diagnosis results. The
upper limit of total nitrogen application described below is
determined based on this nitrogen fertility. “Wet incubation
nitrogen,” “autoclave-extractable nitrogen,” and “raw soil
incubation nitrogen,” which are analytical parameters used
for paddy rice, field crops, and vegetables grown outdoors,
show stable values for a long period. Therefore, a value from
analysis in the last 3-year period is useful. Performing soil
diagnosis every 3 years is sufficient after registration. For
“nitrate nitrogen”, which is an analytical parameter used for
greenhouse vegetables, an analysis value within the last
1-year period must be used. Soil diagnosis is conducted
every year after registration.
Total nitrogen application consists of the integrated
amount of nitrogen component derived from organic materials including compost, chemical fertilizers, and organic
fertilizers used in the period relevant to each crop. The
standard fertilizer application corresponding to the soil nitrogen fertility level is fundamentally applicable to the upper
limit of total nitrogen application. However, the standard
fertilizer application might vary for some crops by zone
category or soil category. The maximum value of the standard fertilizer application was used for such crops.
The upper limit of chemical fertilizer application is
determined using the remaining nitrogen amount obtained
by subtracting the nitrogen supply when the lower limit of
organic matter including compost is applied from the upper
limit of the total nitrogen application. However, fertility
enhancement by the application of organic matter including
compost is required in a field with soil nitrogen fertility
classified as “low.” Therefore, the value of “middle” soil
nitrogen fertility was applied for the upper limit of chemical
fertilizer application.
The lower limit of application of organic materials
including compost represents the amount of organic material
which must be applied annually to fields using the “amount
of compost application to maintain soil fertility” shown in
the Hokkaido fertilizer application guidelines. The value is
10 Mg ha
−1 for paddy rice and field crops, 20 Mg ha
−1 for
vegetables, flowers, and ornamental plants grown outdoors
and fruit trees, and 40 Mg ha
−1 for vegetables, flowers, and
ornamental plants grown in greenhouses.
However, for cases in which only a small amount of
compost is available, or when quality benefits are achieved
in crops more easily without compost application, the concept described below is used for the application of organic
materials including compost: Organic matter that can supply
nitrogen component or dry weight equivalent to compost is
useful as “organics equivalent to compost.” Organic materials such as fish meal and fermented chicken manure can be
converted into compost with an equivalent nitrogen component (Table 5.20). Till in, green manure can also be
converted into compost based on dry weight. Therefore, the
standard can be met using by applying appropriate organic
material instead of using compost.
Nitrogen mineralization occurs in compost during periods
when no crop is grown. It is therefore feared that the
application of large quantities of compost might become a
source of environmental pollution such as groundwater
contamination. For that reason, an upper limit of compost
application amount is set for compost containing a high
percentage of nitrogen-rich cattle manure, such as cattle
manure/straw compost and cattle manure/bedding compost.
170
T. Nakatsuji et al.