Ryusaku Matsuba ([email protected]) and Shinjiro Sato · Ryusaku Matsuba1) ([email protected])...
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Ryusaku Matsuba 1) ([email protected] ) and Shinjiro Sato 1) 1) Graduate School of Engineering, Soka University, Tokyo, Japan 2015 ASA-CSSA-SSSA International Annual Meeting, November 15-18, Minneapolis, MN Controlled-released fertilizers (CRFs) are classified into 3 different types; slow-released fertilizers, coated fertilizers, and fertilizers containing nitrification inhibitors. CRFs have been reported to show higher fertilizer effects than soluble fertilizers such as urea and ammonium sulfate. Vegetables such as spinach and mustard spinach can contain high nitrate content among other vegetables. Consumption of vegetables with high nitrate content may cause methemoglobinemia. Therefore, it is necessary to reduce the nitrate content of these vegetables. It’s been reported that CRF application can reduce N fertilizer application rates while increasing crop yields. Also, CRF application for vegetable production can reduce nitrate content in some vegetables. Effects of application of different CRFs on nitrate content and yield of Japanese mustard spinach (Brassica rapa) were evaluated through 2 pot experiments. • Typic Dystrochrept (0-15 cm; Tokyo, Japan) • Oven dried (45 o C) with 2 mm sieved for experiment Table 1. Soil chemical characteristics • Japanese mustard spinach (Brassica rapa) • Nitrogen: ○ Urea (46.6% N) as quickly available fertilizer (UR) ○ CDU (30% N) as slow-released fertilizer (SF) ○ Coated urea (42% N) as resin-coated fertilizer (CF) ○ Urea containing nitrificaiton inhibitors (0.4% AM*; 46.6% N) as fertilizer containing nitrification inhibitor (NI) (* 2-amino-4-choro-6-methylepyrimidine) • Phosphate: Superphosphate (17.5% P 2 O 5 ) • Potassium: Potassium chloride (52.4% K 2 O) ① The same amount of N was applied based on recommended N rate (140 kg ha -1 ) for the spinach from different fertilizers. • Five treatments included no fertilizers added (CR), urea (UR), slow- released fertilizer (SF), resin-coated fertilizer (CF), and fertilizer containing nitrification inhibitor (NI). ② The recommend and reduced rates of N was applied from different fertilizers. • Ten treatments included the recommended rate (CR, SF, CF, and NI), 10%-reduced rate for SF, CF, and NI (SF10, CF10, and NI10), and 20%-reduced rate for SF, CF, and NI (SF20, CF20, and NI20). • Plant dry weight • Plant nitrate content • Plant nitrate accumulation (dry weight x nitrate content) pH EC (µS cm -1 ) Total C (g kg -1 ) Total N (g kg -1 ) C/N NO 3 - -N (mg kg -1 ) NH 4 + -N (mg kg -1 ) 7.17 51.9 39.9 2.83 14.1 0.056 12.0 b a a a a 0 1 2 3 CR UR SF CF NI Dry weight (g) Fig. 2 Dry weight of Japanese mustard spinach a bc c b c 0 750 1500 2250 3000 3750 CR UR SF CF NI Nitrate content (mg kg -1 ) Fig. 3 Nitrate content of Japanese mustard spinach b a ab a ab 0 2 4 6 CR UR SF CF NI Nitrate accumulation (mg) Fig. 4 Nitrate accumulation of Japanese mustard spinach a a ab bcd ab d d abc d cd 0 1 2 3 UR SF SF10 SF20 CF CF10 CF20 NI NI10 NI20 Dry weight(g) Fig. 6 Dry weight of Japanese mustard spinach bc cd cd d ab bc a bc cd cd 0 2 4 6 UR SF SF10 SF20 CR CR10 CR20 NI NI10 NI20 Nitrate accumulation (mg) b b b b b ab a b b b 0 1000 2000 3000 4000 UR SF SF10 SF20 CR CR10 CR20 NI NI10 NI20 Nitrate content (mg kg -1 ) Fig. 7 Nitrate content of Japanese mustard spinach Fig. 8 Nitrate accumulation of Japanese mustard spinach ・There were no significant differences in the dry weights among all treatments (Fig.2). ・SF and NI treatments had lower nitrate content than other treatments (Fig. 3). ・SF and NI treatments had lower nitrate accumulation than other treatments (Fig.4 ). ・The CRFs used in this study may have equivalent fertilizer effects compared with readily soluble fertilizer. ・The dry weights in SF and SF10 were comparable (Fig. 6). ・SF, SF10, and SF20 had lower nitrate content than other treatments (Fig. 7). ・SF, SF10, and SF20 showed significantly lower nitrate accumulation than did UR (Fig. 8). ・It appeared that SF reacted differently from CF and NI in the soil because it was urea condensation Product. The CRFs may have equivalent fertilizer effects compared with readily soluble fertilizer for Japanese spinach grown in pots. It was found that SF could cause low nitrate accumulation in spinach due to slow release capability, hence gradual plant absorption, without negatively affecting the crop yield. Fig. 1 Japanese Mustard Spinach (Brassica rapa) Fig. 5 First pot experiment Fig. 9 Second pot experiment
Transcript of Ryusaku Matsuba ([email protected]) and Shinjiro Sato · Ryusaku Matsuba1) ([email protected])...
Ryusaku Matsuba1) ([email protected]) and Shinjiro Sato1) 1) Graduate School of Engineering, Soka University, Tokyo, Japan
2015 ASA-CSSA-SSSA International Annual Meeting, November 15-18, Minneapolis, MN
Controlled-released fertilizers (CRFs) are classified into 3 different types; slow-released fertilizers, coated fertilizers, and fertilizers containing nitrification inhibitors. CRFs have been reported to show higher fertilizer effects than soluble fertilizers such as urea and ammonium sulfate.
Vegetables such as spinach and mustard spinach can contain high nitrate content among other vegetables. Consumption of vegetables with high nitrate content may cause methemoglobinemia. Therefore, it is necessary to reduce the nitrate content of these vegetables.
It’s been reported that CRF application can reduce N fertilizer application rates while increasing crop yields. Also, CRF application for vegetable production can reduce nitrate content in some vegetables.
Effects of application of different CRFs on nitrate content and yield of Japanese mustard spinach (Brassica rapa) were evaluated through 2 pot experiments.
• Typic Dystrochrept (0-15 cm; Tokyo, Japan) • Oven dried (45oC) with 2 mm sieved for experiment
Table 1. Soil chemical characteristics
• Japanese mustard spinach (Brassica rapa)
• Nitrogen: ○ Urea (46.6% N) as quickly available fertilizer (UR) ○ CDU (30% N) as slow-released fertilizer (SF) ○ Coated urea (42% N) as resin-coated fertilizer (CF) ○ Urea containing nitrificaiton inhibitors (0.4% AM*; 46.6% N) as
fertilizer containing nitrification inhibitor (NI) (* 2-amino-4-choro-6-methylepyrimidine)
• Phosphate: Superphosphate (17.5% P2O5) • Potassium: Potassium chloride (52.4% K2O)
① The same amount of N was applied based on recommended N rate
(140 kg ha-1) for the spinach from different fertilizers. • Five treatments included no fertilizers added (CR), urea (UR), slow-
released fertilizer (SF), resin-coated fertilizer (CF), and fertilizer containing nitrification inhibitor (NI).
② The recommend and reduced rates of N was applied from different
fertilizers. • Ten treatments included the recommended rate (CR, SF, CF, and
NI), 10%-reduced rate for SF, CF, and NI (SF10, CF10, and NI10), and 20%-reduced rate for SF, CF, and NI (SF20, CF20, and NI20).
• Plant dry weight • Plant nitrate content • Plant nitrate accumulation (dry weight x nitrate content)
pH
EC (µS cm-1)
Total C (g kg-1)
Total N (g kg-1)
C/N
NO3--N
(mg kg-1) NH4
+-N (mg kg-1)
7.17 51.9 39.9 2.83 14.1 0.056 12.0
b
a a a
a
0
1
2
3
CR UR SF CF NI
Dry
wei
ght (
g)
Fig. 2 Dry weight of Japanese mustard spinach
a
bc
c
b
c
0
750
1500
2250
3000
3750
CR UR SF CF NI
Nitr
ate
cont
ent (
mg
kg-1
)
Fig. 3 Nitrate content of Japanese mustard spinach
b
a
ab
a
ab
0
2
4
6
CR UR SF CF NI
Nitr
ate
accu
mul
atio
n (m
g)
Fig. 4 Nitrate accumulation of Japanese mustard spinach
a a ab
bcd
ab
d d
abc
d cd
0
1
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3
UR
S
F S
F10
SF2
0 C
F C
F10
CF2
0 NI
NI1
0 N
I20
Dry
wei
ght(g
)
Fig. 6 Dry weight of Japanese mustard spinach
bc
cd cd d
ab
bc
a
bc cd
cd
0
2
4
6
UR
S
F S
F10
SF2
0 C
R
CR
10
CR
20
NI
NI1
0 N
I20 N
itrat
e ac
cum
ulat
ion
(mg)
b b b b
b
ab
a
b b
b
0
1000
2000
3000
4000
UR
S
F S
F10
SF2
0 C
R
CR
10
CR
20
NI
NI1
0 N
I20
Nitr
ate
cont
ent (
mg
kg-1
)
Fig. 7 Nitrate content of Japanese mustard spinach
Fig. 8 Nitrate accumulation of Japanese mustard spinach
・There were no significant differences in the dry weights among all treatments (Fig.2). ・SF and NI treatments had lower nitrate content than other treatments (Fig. 3). ・SF and NI treatments had lower nitrate accumulation than other treatments (Fig.4 ). ・The CRFs used in this study may have equivalent fertilizer effects compared with readily
soluble fertilizer.
・The dry weights in SF and SF10 were comparable (Fig. 6). ・SF, SF10, and SF20 had lower nitrate content than other treatments (Fig. 7). ・SF, SF10, and SF20 showed significantly lower nitrate accumulation than did UR (Fig. 8). ・It appeared that SF reacted differently from CF and NI in the soil because it was urea
condensation Product.
p The CRFs may have equivalent fertilizer effects compared with readily soluble fertilizer for Japanese spinach grown in pots.
p It was found that SF could cause low nitrate accumulation in spinach due to slow release capability, hence gradual plant absorption, without negatively affecting the crop yield.
Fig. 1 Japanese Mustard Spinach (Brassica rapa)
Fig. 5 First pot experiment
Fig. 9 Second pot experiment
