presentation witzenhausen nov2009
Post on 18-Oct-2014
317 views
DESCRIPTION
Quality of cattle manureTRANSCRIPT
Cattle diet composition and fertilizer value of excreta
Egbert A. Lantinga
Group of Biological Farming SystemsDepartment of Plant [email protected]
Cattle dung
Cattle slurry
Phytotoxicity: lab vs. field experiments
Long(er)-term effects
Outline
(Bosker, Hoekstra & Lantinga, 2002)
Influence of feeding strategy on growth and rejection
of herbage around dung pats and their decomposition- Continously grazed pasture- Experimental period: 6 weeks- Artificial dung pats (2.5 kg fresh dung; Ø 31 cm;
height 9 cm)- Dung from 4 diverging cattle farms
CATTLE DUNG
Grass cages
4 grass cages
Results: Index factors (column mean=100)
Index factors
Cage: undisturbed DM yield (Ø 64 cm)
R1: DM yield within grazed dung area
R2: DM yield around grazed dung area
PDD: % dung disappeared
(+ straw)
Cattle slurry
Low C/N-ratio + high Nmin-content: - phytotoxic effects on herbage? (ammonia, salts, heavy metals, biogenic amines, phenolic compounds)- herbage rejection by grazing cattle? (volatile fatty acids, ammonia and
volatile amines)
Experiments: - bio-assay (germination of cress seeds) - field trial (herbage N recovery and
grazing behaviour: change in sward height in manured plots)
(Reijs, Meijer, Bakker and Lantinga, 2003)
Roughages in cattle diets
Grazed Grass Maize WheatWheat
grass silage silage silage straw APMlac + - - + + OSK + - - - - APMdry - + - + + MAR + + + - -
Bio-assay: Germination index (ammonia)
Bio-assay: Germination index (salinity)
Bio-assay: Germination index (copper)
Bio-assay: Germination index(phenol)
Bio-assay: Germination index
Phytotoxic effect: MAR > APMlac > OSK > APMdry Slurry C/N ratio: 10 9 14 16
Germination inhibiting effects:
1. NH3/NH4+
2. salinity (electronic conductivity)3. Cu (weak)4. Phenol (no)
Grazing behaviour: Change in Herbage Height (CHH; cm) after one week (no fertilizer effects!)
Ranking order
0 N > APMdry > OSK > APMlac > MAR
-1.4 -0.4 -0.2 -0.1 +0.6
Positively and significantly correlated with slurry NH3/NH4
+-N content (R2 = 0.98)
Fertilizer value (growth period 5 weeks)
straw in diets →
0 N
Bio-assay phytotoxicity and field slurry quality
Ranking order: the slurry with the greatest phytotoxicity (lab) showed highest herbage yield after five weeks (field)!
- Buffering capacity soil- Sensitivity differences between roots of cress
seedlings and established grass root systems- Straw (C/N-ratio ~ 80): temporary N-immobilization
Longer term fertilizer effects: one year
Field experiment: effects different diets on N utilization from cattle slurry
MFE (mineral fertilizer equivalent; %) = 100 * EFR / total slurry-N
EFR = equivalent fertilizer N response (i.e. amount of mineral fertilizer N needed to attain the same N yield as with slurry)
Two grassland fields on sand: NEW and OLD (age 5 vs ~50 years); OLD field higher groundwater level → higher denitrification losses (wet spring)
(Reijs, Sonneveld, SØrensen, Schils, Groot and Lantinga, 2007)
NEW
OLD
O
OO
O
O: 50% straw
Long-term soil quality effects (200 years)
Initial and equilibrium topsoil characteristics after long-term applications (180 kg N ha-1 yr-1) of two extreme slurries (C:N
total
14.5 vs. 26.3)
Model: FarmDances (J.C.J. Groot, WUR)
Long-term soil quality effects (200 years)
Inclusion of chopped straw in cattle diets (~5% on DM basis): herbage rejection grazing cattle ↓; dung decomposition rate↑; temporary immobilization slurry Nmin → short-term (one year) N fertilizing effect ~ 0
Lab bio-assays with cress seeds are not realistic to assess phytotoxity of slurry for the field situation
Compensation of reduced first year’s N availability of slurry with high C:Ntotal ratio’s will take some decades (gradually increasing soil N delivery due to N accumulation)
CONCLUSIONS