12 Dec 2012

Efficiency of resource use

recovery efficiency for different strategies
Harvesting the long term N*P experiment


The yield and fertilizer use data can be used to estimate the efficiency of various fertilizer strategies in these types of farming systems. The table below provides estimates of the four common nutrient use efficiencies (Dobermann 2007). Nitrogen recoveries almost tripled where P was added, and similarly, P recoveries increased greatly where N was added. Irrespective of the indicator used, the interaction of N and P is clear, with improved recoveries or higher productivity where nutrients are supplied together.

The effect of N and P on nitrogen and phosphorus use efficiency indicators partial factor productivity (PFP), partial nutrient balance (PNB), agronomic efficiency (AE) and recovery efficiency in grain (REgr) from a long term fertilizer experiment in southeastern Australia.

N rate
kg/ha
P rate kg/ha
Efficiency indicator
PFP
kg/kgN
PNB
kgN/kgN
AE
Δkg/kgN
REgr
ΔkgN/kgN
20
0
85
1.97
5
0.14
80
0
22
0.56
2
0.11
20
18
115
2.60
16
0.36
80
18
31
0.75
6
0.29
N rate
kg/ha
P rate
kg/ha
PFP
kg/kgP
PNB
kgP/kgP
AE
Δkg/kgP
REgr
ΔkgP/kgP
0
9
162
0.61
31
0.13
0
18
83
0.32
18
0.02
80
9
201
0.73
57
0.21
80
18
109
0.40
37
0.14

Additional Resources

Summary FileSize: 2.44 MB




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