department of soil management and soil care department of applied analytical and physical chemistry...
TRANSCRIPT
Department of Soil Management and Soil CareDepartment of Applied Analytical and Physical Chemistry
INFLUENCE OF NITRIFICATION INHIBITORS ON SOIL N DYNAMICS
AFTER INCORPORATION OF VEGETABLE CROP RESIDUES: A
FIELD STUDY
Georges Hofman Barbara Chaves Stefaan
De NevePascal Boeckx Oswald Van
Cleemput
Outline
Introduction Materials and methods Results Discussion Conclusion
Introduction
The Netherlands
The Walloon Region
Problems with NOProblems with NO33---N leaching-N leaching
= Vegetable region= Vegetable region
Introduction
Crop Crop residues
Large amounts crop residues (up to 60 t fresh material ha-1) High N content (2 - 4% N on dry matter) Large and fast N release from crop residue (up to 150 kg N ha-1) High risk of NO3
- leaching
Objective
Can nitrification inhibitors (DCD and
DMPP) reduce nitrification and NO3-
leaching after incorporation of vegetable
crop residues?
Materials and methods
Block 3
Block 2
Block 1
Randomised block design with 3 replicatesRandomised block design with 3 replicatesSilt loamSilt loam
Cauliflower residuesCauliflower residues~ 452 kg N ha~ 452 kg N ha-1 -1 sandy loamsandy loam
DMPP ~ 1,9 kg a.c. haDMPP ~ 1,9 kg a.c. ha-1-1
DCD ~ 19 kg a.c. haDCD ~ 19 kg a.c. ha-1-1
Cauliflower
SoilCauliflower + DCD
Cauliflower + DMPP
Materials and methods
6 sampling dates • with an auger • to a depth of 90 cm in 3 layers: 0-30 cm, 30-60 cm, 60-90 cm
Mineral N • extraction with (1N) KCl• continuous flow autoanalyser
NH4+-N and NO3
--N
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0tim e (d ay s)
-2 0
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
1 4 0
1 6 0
NH
4+ c
onte
nt (
kg N
ha-
1 )
u n am en d ed so ilcau lif lo w er o n lyD C DD M P P
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0tim e (d ay s)
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
9 0
1 0 0
NO
3- co
nten
t (kg
N h
a-1 )
u n am en d ed so ilcau lif lo w er o n lyD C DD M P P
Mineral N
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0tim e (d ay s)
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
min
eral
N (
kg N
ha-
1 )
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0tim e (d ay s)
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
1 4 0
1 6 0
1 8 0
2 0 0
min
eral
N (
kg N
ha-
1 )
u n am en d ed so ilcau lif lo w er o n lyD C DD M P P
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 2 0 0tim e (d ay s)
5
1 0
1 5
2 0
2 5
3 0
3 5
4 0
4 5
min
eral
N (
kg N
ha-
1 )
Discussion
0-30 cmMineral N in DCD > mineral N in cauliflower only
N release from DCD itself (67% N = 13 kg N ha-1)
priming effect induced by DCD (Gioacchini et al., 2002;
Chaves et al., 2006 )
30-60 cm and 60-90 cmMineral N in DMPP < mineral N in cauliflower only and DCD
Only DMPP reduced NO3- leaching
Conclusions
DMPP and DCD
Increased NH4--N in top 30 cm
Reduced NO3--N in top 30 cm
DMPP
Reduced NO3--N in 30-90 cm layer
DMPP can reduce NO3- leaching
DCD
Increased mineral N in 0-30 cm layer (N release from
DCD and priming effect)
No reduction in NO3- leaching
Thank you for your attention!!