Biologically adjusted P cycle as a measure to reduce P losses, an example for Finnish agriculture Eila Turtola (1), Riitta Lemola (1), Jouni Nousiainen (2), Pekka Huhtanen (3), Risto Uusitalo (1) and Elena Valkama (1) (1) MTT, Plant Production Research (2) MTT, Biotechnology and Food Research (3) SLU, Agricultural Research for Nothern Sweden
COST 869, Wageningen, May 19, 2009
Starting -1points:
Specialization in livestock and plant production
t P a-1
tNa
100000
320000
P fertilisation is obviously the most 240000 important background factor for DRP (bioavailable PP) losses from fields to waters 160000
High chemical fertilizer inputs
80000 60000 40000 20000
P fertilisation rates in Deposition Finland were high starting from theNbeginning of fixation 1960s. Manure Fertilization Output
Fertilisation has been reduced considerably in the last 15-20 years.
Deposition Weathering Manure Fertilization Output
Antikainen et al. 2005
2000
1990
1980
1970
1960
1950
1940
1930
1920
1910
2000
1990
0
1980
1970
1960
1950
1940
1930
1920
1910
In80000 modern agriculture, inputs of commercial fertilizers have been large0
(Sweden +2, Norway +13, Denmark +11, Netherlands+16, Hungary -15 kg/ha) .
Karjanlanta Manure
Sato Yield
Tase Bal
30 25 20 15 10 5
2007
2005
2003
2001
1999
1997
1995
1993
1991
1989
0 1987
The average P balance was +30 kg/ha in the end of 1980s, but is now +6 kg/ha
Ostolann. Chemic
1985
P inputs in manure and outputs in yield have remained stationary
35
Fosfori, kg/ha Phosphorus, kg/ha
From the highest levels in late 1980s (28 kg/ha) the chemical fertilizer inputs of P have decreased down to 8 kg/ha
Whole Finland
12 10 8 6 4 2 2001-2005
1996-2000
1991-1995
1986-1990
1981-1985
1976-1980
1971-1975
1966-1970
1961-1965
0
South-Western Finland
20 18 16 14 12 10 8 6 4
Uusitalo et al. 2007
2001-2005
1996-2000
1991-1995
1986-1990
1981-1985
1976-1980
1971-1975
1966-1970
2 0 1961-1965
Consequently, national monitoring studies have found only small or no decrease in P concentrations on agriculturally loaded rivers
14
1955-1960
Due to still positive balances, soil test P has not decreased considerably during the last 15-20 years, or has remained stationary (’good’) in regions with intensive animal production as in SouthWestern Finland
Soil test P, mg/l P-luku, mg/l
The average soil test P (PAc) was raised from 5 mg/l (’moderate’) to 12-14 mg/l (’satisfactory’) by the surplus P balances of 20-30 kg/ha
mg/l SoilMaan testP-luku, P, mg/l
16
P fertilisation and P balance on Finnish dairy farms 45
Still, livestock farms use commercial fertilizers. E.g. in dairy farms, fertilizer P seems to raise directly the P balances
40 35
P-balance (kg/ha)
Manure P is produced and used mostly in regions of concentrated livestock production
30 y = 1.078x + 1.56 R2 = 0.854
25 20 15 10 5 0 0
5
10
15
20
25
30
35
P-fertizer (kg/ha)
Since crop yields, at least in the national and regional levels, have not been affected by the recent, lower P fertilisation, is there further potential for reduction?
Tuori et al.
40
Moreover, there may be potential to adjust animal feeding in terms of P, and reach lower P contents in manure Manure-P, kg/ha
Manure-P, fur animals kg/ha 0 0,01-0,49 0,5-1,9 2,0-4,9 5,0-9,9 10-20 20-50 50-100
Maps: Kaarina Grek and Harri Lilja MTT
We set 2 questions: >> How large is the potential for adjusting P use further in Finnish agriculture (feeding of livestock and fertilisation of agricultural crops) without lowering the production? >> How large is the related potential for reduction of DRP losses to surface waters?
Step 1: Comparison of current P feeding of animals to that justified by biological responses according to feeding trials, i.e. avoiding overuse ● The current P content of manure (year 2005) was estimated Renewal
●New, lower P content of manures (for cow, pig, poultry and fur animals) were then calculated with biological response functions, taking into account economic effects (no negative effects on the net income, Huhtanen et al.)
Feed import
Commercial fertilizers Sold plant products
Storage and feeding
Plant production
Nutrient balances
Milk production
Manure storage
Nutrient losses
Pekka Huhtanen SLU
Sold animals
Sold milk & animals
Bying Selling
Result (1): Adjustment of P feeding would result in 12% lower P content in manure
Area
Current manure-P Adjusted manure-P mill.kg/year mill.kg/year
Whole Finland Uusimaa Varsinais-Suomi Pohjanmaa
16,5 0,48 1,9 2,9
Jouni Nousiainen MTT, Pekka Huhtanen SLU
14,5 0,43 1,7 2,6
Step 2: Comparison of current P use in plant production to that justified by biological responses according to fertilisation trials, i.e. avoiding overuse ● The crop responses to soil test P and P fertilisation were considered, but economy was not taken into account
● Need of P fertilisation was estimated according to amounts giving maximum yields (Valkama et al. 2009)
30
"Low"
"Medium and high"
Yield increase (%)
25 20 (28)
15 10 5 0 -5
(12)
(48) (21)
