Potato Variety Response to Potato Variety Response to Phosphorus FertilizerPhosphorus Fertilizer

Mike Thornton, Deron Beck, Jeff Stark and Mike Thornton, Deron Beck, Jeff Stark and Bryan HopkinsBryan Hopkins

Petiole P status and yield are relatedPetiole P status and yield are related

300

400

500

600

700

10 20 30 40 50 60 70 80 90

Days from tuber set till tops < 0.22%P

Total Yield (cwt/ac)

Source: Westermann and Kleinkopf, 1983

Y = 237 + 7.24X – 0.026 X 2

R 2 = 0.76

Daily uptake rate of P during three years Daily uptake rate of P during three years at Aberdeen, IDat Aberdeen, ID

0

0.1

0.2

0.3

0.4

0 20 40 60 80 100

Days after emergence

P uptake (lbs/ac-day)

Source: Stark, Westermann and Hopkins, 2004

Cultivar use in 2007Cultivar use in 2007Cultivar use in 2007Cultivar use in 2007

IdahoOregon

Washington

Shepody

6LS

Do potato varieties differ in their Do potato varieties differ in their response to P fertilizer?response to P fertilizer?

Differences in yield responseDifferences in yield response Differences in P uptake or petiole levelsDifferences in P uptake or petiole levels Differences in P removal by tubersDifferences in P removal by tubers

Varieties with poor root systems or Varieties with poor root systems or susceptibility to early die might need more Psusceptibility to early die might need more P

Year pH Lime Soil P (ppm)

Broadcast(P2O5/ac)

Starter(P2O5/ac)

2005 8.2 1% 15 130 lbs 40 to 80 lbs

2006 7.7 2% 8 210 lbs 40 to 80 lbs

2007 8.2 1% 5 290 lbs 40 to 80 lbs

Soil test values (0 to 12”)

UI recommendation

Methods-Split plot design with 4 rates of P2O5 (0,100, 200, 300 lbs per acre) broadcast as 11-52-0 and incorporated prior to planting. Urea used to balance N rates.-Four cultivars (Burbank, Ranger, Shepody, 6LS) planted as subplots

Influence of fertilizer rate on marketable yield

0

100

200

300

400

500

600

700

0lb P 100lb P 200lb P 300lb P

>12

6-12

4-6

0-4

0

100

200

300

400

500

600

700

0lb P 100lb P 200lb P 300lb P

Russet Burbank 6 LS

Influence of fertilizer rate on tuber size profile

Vine GrowthVine Growth6LS

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12

Weeks after Emergence

% G

C 6LS 0

6LS 200

Vine GrowthVine GrowthRusset Brubank

0

10

20

30

40

50

60

70

80

90

100

1 2 3 4 5 6 7 8 9 10 11 12

Weeks after emergence

% G

C RB 0

RB 200

Influence of fertilizer rate on plant growth

0.15

0.25

0.35

0.45

0 100 200 300

Fertilizer Rate (lbs P2O5)

% total P

Shepody

Ranger

Russet B.

6LS

Deficient

Influence of fertilizer rate on petiole P concentration

Influence of fertilizer rate on plant P uptake on Aug 15

Influence of fertilizer rate on P removal in tubers

SUMMARYSUMMARY

Plant development was delayed and Plant development was delayed and senescence increased at low P rates, senescence increased at low P rates, especially in Shepodyespecially in Shepody

Petiole P levels were highest in Ranger, Petiole P levels were highest in Ranger, lowest in Russet Burbank and 6LSlowest in Russet Burbank and 6LS

Ranger and 6LS had the strongest yield Ranger and 6LS had the strongest yield response to fertilizer P, and removed up to response to fertilizer P, and removed up to 33 lbs/acre P in tubers at harvest33 lbs/acre P in tubers at harvest

For information about potatoes, visit:

Idaho Center for Potato Research and Education

http://www.ag.uidaho.edu/potato