ishs plum and prune symposium; palermo, italy 17.-19.03.08 1 the effect of foliar fertilization with...

ISHS Plum and Prune Symposium; Palermo, Italy 17.-19.03.08

1

The Effect of Foliar Fertilization with Potassium and Magnesium on Fruit Quality in Plums (Prunus domestica L.)

Eivind Vangdal, Sigrid Flatland and Ingvild MehlBioforsk Vest Ullensvang, Norway


2

This presentation includes:

• Why use foliar fertilization

• Present status of major nutrients in plum and present recommendations for foliar fertilization in plums in Norway

• Results from field experiments

• Conclusions


3

Why use foliar fertilization?

• Strong focus on fruit quality

• Good foliar fertilizers are available

• Are fruit trees in high density orchards able to get the nutritients needed through their roots for optimum fruit quality?


4

Standard fertilization in plums in Norway:

• N-P-K mineral fertilizer on the soil in the spring Contains some calcium and magnesium and trace elements like Manganese, Boron, Zink etc.

5

Leaf analysis of plums:

Element Recommended range

Average in field experiment

Nirogen* 2,3 – 2,8 2,37

Phosphorus* 0,15 – 0,3 0,24

Potassium* 2,2 – 2,8 2,59

Calcium* 2,0 – 3,0 2,22

Magnesium* 0,25 – 0,40 0,31

Boron** 20 – 50

Manganese** 30 – 60

Zink** 20 - 150*) Per cent of DM; **)ppm of DM


6

Standard fertilization in plums in Norway:

• N-P-K mineral fertilizer (6-5-20 or 11-5-18) on the soil in the spring

• Foliar fertilization:– Calcium (every second week from two weeks after

petal fall until 2 weeks prior to estimated harvest date)

– Boron (once after harvest, once two weeks prior to flowering

– Nirogen (urea after harvest)


7

Field experiment with foliar fertilization with Mg and K

A: Foliar fertilization programme with N, P, K, Ca, Mg, Cu, S, B, Mn, Zn (Reduced N-P-K on the ground)

Stadium week N P Ca Other nutrients

D / 54 16 3 kg urea

1 kg Cu

E2 / 57-58 18 3 kg urea

1 kg MAP 2 kg S + 1 kg Solubor

End of flowering

21 1 kg urea

1 kg MAP 2 kg S + 5 kg MgSO4

After flowering

24 1 kg urea

1 kg MAP 2,5 kg CaCl2 0,5 l Mantrac + 0,2 l Zintrac

27 2,5 kg CaCl2

30 2,5 kg CaCl2

31 3 kg MKP

33 2,5 kg CaCl2

Post-harvest

38 5 kg urea

1 kg MAP 5 kg MgSO4 + 0,5 l Mantrac

0,2 l Zintrac + 1 kg Solubor

Foliar fertilization programme:


9

Field experiment with foliar fertilization with Mg and K

• A: Foliar fertilization programme with N, P, K,

Ca, Mg etc. (in additon to N-P-K on the

ground)

• B: As A + 2 x 5 kg MgSO4 (week 24 and 27)

• C: As A + 2 x 3 kg MKP (week 29 and 32)• D: As A + both Mg and K as in C and D

• Cultivars: Avalon, Excalibur and Reeves

Results: yield, fruit size and colour

Yield

(tons/ha)

Fruit size (g)

Ground colour

Blush clour

Control 18,4 55 4,8 5,0

+ 2 x Mg 23,7 56 5,2 4,9

+ 2 x K 25,7 54 4,6 5,1

+ 2 x both Mg and K

18,9 51 4,4 4,6

P-value n.s. n.s. n.s. n.s.

Results: internal quality factors

Firmness Soluble solids

content

Titratable acidity

SSC:

acidity ratio

Control 73 12,3 1,26 9,64

+ 2 x Mg 73 12,1 1,26 9,55

+ 2 x K 74 12,1 1,26 9,57

+ 2 x both Mg and K

74 12,3 1,28 9,61

P-value n.s. n.s. n.s. n.s.

Results: leaf analysis

N P K Mg Ca

Control 2,37 0,25 2,56 0,32 2,30

+ 2 x Mg 2,36 0,22 2,5 0,32 2,26

+ 2 x K 2,36 0,23 2,72 0,30 2,18

+ 2 x both Mg and K

2,31 0,24 2,66 0,32 2,25

Results: fruit analysis

N P K Mg Ca

Control 0,74 0,15 1,33 0,070 0.140

+ 2 x Mg 0,74 0,15 0,98 0,070 0,090

+ 2 x K 0,77 0,13 1,23 0,043 0,063

+ 2 x both Mg and K

0,78 0,16 1,23 0,056 0,107

Results: yield, fruit size and colour

Yield

(tons/ha)

Fruit size (g)

Ground colour

Blush clour

Control 16,1 41 6,2 5,5

Foliar fertilizing programme

19,2 39 5,5 5,3

Results: internal quality factors

Firmness Soluble solids

content

Titratable acidity

SSC:

acidity ratio

Control 63 11,3 1,41 8,01


65 11,1 1,42 7,82

Results: fruit analysis

N P K Mg Ca

Control 0,83 0,16 1,33 0,069 0.140


0,99 0,11 0,99 0,045 0,090


17

Concluding remarks:

• The results shown in this presentations do not indicate strong effects of foliar application with Magnesium and Potassium

• Previous research and observations show good effects of foliar applications of Calcium, Boron (and in some situations) Nitrogen

• The fieled experiment with foliar fertilization with Mg and K will be repeated this year including studies of effects on shelf life of plums

Thank you for your attention!

ishs plum and prune symposium; palermo, italy 17.-19.03.08 1 the effect of foliar fertilization with...

Documents