maluma fertiliser norms and practices - The Maluma Blog

Nutrient distribution in Avocado plant – absolute amounts. 1000. 1500. 2000. N u trien. t c on tent in g. /tre e. Fruit. Leaves. New shoots. Branches...

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MALUMA FERTILISER NORMS AND PRACTICES AA ERNST

SOURCE:

South Africa 

Fertilization guidelines based on: –

Sampling for leaf analyses and norms



Soils analyses



Applciations based on phenological stages -> growth cycle approach



Very few fertilizer applications while tree establishment



Foliar Zn and B application recommended monthly during active shoot growth, specially in young trees

South Africa 

Split nitrogen applications recommended: –

Caution for applying nitrogen too early



Nitrogen as an important tool to manipulate vegetative and reproductive growth



Critical is the overall nutrient management during summer flush to ensure future productivity



Physiological post-harvest fruit disorder -> “gray pulp” the major problem for local and overseas marketing due to N : Ca ratio imbalances



Calcium as key nutrient to improve fruit quality

Nutrient distribution in Avocado plant – absolute amounts

Variety: Hass; August 2001,

Fruit Leaves

2000

New shoots Branches

Nutrient content in g/tree

1500

Trunk Root & Rootstock

1000

500

0 Nitrogen

Phosphorus

Potassium

Nitrogen is distributed in fruits, leaves, branches and roots. Phosphorus is mainly located in the roots + rootstock and the branches of the tree. Potassium is mainly located in fruits and branches. Source: Rosecrance & Lovatt (2003) - Califoria

Nutrient Removal of Avocado fruits Based on 10 t/ha fresh weight Nutrient

% of dry weight

Kg/ha

Nutrient

ppm of dry weight

Kg/ha

N

0.54

11.3

Na

400

0.8

P

0.08

1.7

B

19

0.04

K

0.93

19.5

Fe

42

0.09

Ca

0.10

2.1

Zn

18

0.04

Mg

0.24

5.0

Mn

9

0.02

Cl

0.07

1.5

Cu

5

0.01

S

0.30

8.0

Yields in New Zealand: 9.4 metric tons/ha (60 to 200 trees per ha) with average fruit size 260 - 290 g/fruit. Source: Lahav, E 1995

The N : K ratio fits to the 12:11:18

Nutrition of Avocado Nitrogen

Nitrogen 

Nitrogen has a great influence on growth and yield of avocado



There is a relationship between N concentration in the spring grown (autumn sampled) leaves and the yield of avocado –



The optimum N concentration in the leaf is depending on cultivar – – –



(Embleton, 1959)

“Hass” “Fuerte” Other

= 2.2 – 2.4 = 1.7 – 2.0 = 1.9 – 2.2

A split application in 3-4 rates per year is recommended to prevent losses. Source: The Avocado, 2002 ; Lovatt, 2002

Nitrate absorption is more efficient Autumn

Winter

Spring

Summer

Absorption efficiency (%)

60

Whole tree absorption of Nitrogen was highest for N applied in summer

a

50 ab

40 b b

30 20

a

10

b

a

0 Nitrate Source: Zilkah, S. et al. (2000)

Ammonium

a

Nitrogen deficiency

Nutrition of Avocado Phosphorus

Phosphorus deficiency

Leaf loses lustre and turns reddish brown

Nutrition of Avocado Potassium

Potassium deficiency

Necrosis of leaf margins

Nutrition of Avocado Calcium

Calcium 

Calcium related disorders are also internal Calcium distribution problems, mainly between mature and growing regions of the plant and/or in the fruit



Low Avocado fruit Ca levels have been associated with several undesirable fruit characteristics: – – – – – –

Susceptibility to chilling injury Rapid softening/ripening after harvest Flesh discolouration Pulp spot Vascular Browning Susceptibility to Anthracnose

Source: Witney et al. (1990)

Calcium concentration in Avocado fruits 7000

Fruit Ca (mg/kg dm)

6000

Critical Period for Calcium management

5000

in first 11 weeks after fruit set

4000 3000 2000 1000 0 0

5

10

15

weeks after fruit set Source: Witney et al. (1990)

20

25

Calcium concentration in Avocado fruits Proximal end

1 2 20 mm

3

Fruit section

Calcium (µg/g fresh wt)

1

181

2

116

3

73

4

53

5

53

4 The first symptoms of chilling injury are

5

visible at the distal end of avocados, where the Ca concentration is lowest

Distal end Source: Chaplin & Scott (1980)

Calcium and Fruit Quality 26 R2 = 0,61

No° of days to ripen

24 22 20 18 16 14 200

250

300

350

400

450

500

550

Ca concentration in fruits (mg/kg)

Higher Fruit Ca concentration is related to delayed ripening which is increasing fruit Shelf –Life Variety: Hass Source: Hofman et al. (2001)

Calcium and Fruit Quality 5

Anthracnose (1-5)

R2 = 0,77 4

3

2

1 200

250

300

350

400

450

500

550

Ca concentration in fruits (mg/kg)

Higher Fruit Ca concentration is related to a reduced severity of Anthracnose (1= no disease to 5= severe disease) following storage and ripening of “Hass” fruit. Source: Hofman et al. (2001)

60

14

58

12

Calcium in leaf (g/kg dw)

Calcium in fruit (mg/kg fw)

Calcium efficiency varies with rootstock 56 54 52 50 48 46

Hass on Duke 7

Hass on Velvick

10 8 6 4 2 0

Hass on Duke 7

Hass on Velvick

Calcium concentration of Hass avocado leaves and fruit flesh from trees grown on different rootstocks Source: Marques (2000) – from Whiley et al (2001)

Calcium efficiency varies between trees Variety “Hass” Fruit Ca conc (mg/kg)

600

500

400

300

200

100

0

1

2

3

4

5

6

7

8

Individual trees Source: Whiley et al. 2001 – from Vuthapanich et al. 1998

9

10

11

12

13

14

Calcium deficiency

Typical ’tip burn’ of leaf

Magnesium deficiency

Leaves remain green at base and along veins

Sulphur deficiency Sulphur moves slow in plants. Deficiency symptoms therefore manifest in the young leaves.

Fruit is deformed on one side

Nutrition of Avocado Boron

Boron – need 

BORON IS REQUIRED PRIOR TO FLOWERING FOR PROPER FERTILIZATION AND FRUIT SET



FOLIAR APPLICATION OF BORON IS NOT ENOUGH: –

ABSORPTION OF BORON BY MATURE LEAVES IS POOR (DUE TO THE WAXY SURFACE),



BORON IS TAKEN UP BY YOUNG LEAVES



BORON HAS TO BE TRANSLOCATED TO THE INFLORESCENCE



BASE SOIL APPLICATION CAN PREVENT SEVERE BORON DEFICIENCY WITHOUT RISKING TOXICITY EFFECTS



THE SOIL APPLICATION SHOULD BE COMPLIMENTED WITH FOLIAR APPLICATIONS BEFORE FRUIT SET, WHEN NEED IS HIGHEST Source: Robbertse et al., 1992

Boron soil application The effect of soil B application on leaf boron concentrations of Hass grafted to Duke (Mexican or Velvick (Guatemalan) Rootstock. Boron leaf concentration (mg/kg)

60 50 40 Hass/Duke 7

30

Hass/Velvick

20 10 0 0

0.25

0.5

1

2

Boron soil application (kg/ha) Source acc. to: Whiley et al., 1996

3

8

Boron – Critical level for deficiency 

DEFICIENCY SYMPTOMS: –

YELLOWING AND DEFORMATION OF LEAVES



THICKENING OF NODAL REGIONS ON BRANCHES



REDUCED ROOT GROWTH



BRANCH AND TRUNK LESIONS



REDUCED POLLEN VIABILITY



DEFORMED AND SMALLER FRUITS



DEFICIENCY OCCURS AT LEAF BORON CONCENTRATIONS < 25 MG/KG



OPTIMUM LEAF BORON CONCENTRATION –

40-100 MG/KG IN MATURE SUMMER FLUSH LEAVES, BEFORE INFLORESCENCE (ACC. TO ROBBERTSE ET AL, 1995 B > 70 MG/KG)

Source: Whiley et al. 1996 - Australia

Boron deficiency – Cultivars and Rootstocks Rootstock: Cultivar: CULTIVAR

Highly susceptible

Sharwil

Moderate susceptible

Hass

0.5

Reed Moderate tolerant

Fuerte

Boron in leaf (g/kg dw)

BORON DEFICIENCY

Boron uptake efficiency is generally higher for Guatemalan type rootstocks (Edranol, Nabal, Velvick) than those of Mexican type (Duke 7, Topa Topa, Mexicola).

0.4 0.3 0.2 0.1 0

Source: Whiley et al., 1996 Marques (2000) – from Whiley et al. (2001)

Hass on Duke 7 Hass on Velvick

Boron application on B deficient soils 280

Fruit Size (g)

260 240

no B +B

220 200 180 Trial 1

Trial 2

Field Trials: Cultivar Hass, Boron soil applied Leaf boron concentration were also directly correlated to increased Fruit Size Source: Smith et al. (1995)

Boron deficiency

Fruit is deformed on one side

Boron – Critical level for Toxicity 

AVOCADO IS ALSO SENSITIVE TO BORON TOXICITY WHICH LEADS TO A VERY NARROW OPTIMUM LEVEL (FAO 1995)



AVOCADO IS SENSITIVE TO IRRIGATION WATER CONTAINING MORE THAN >92 µM BORON –



GUPTA ET AL. (1985)

TOXICITY SYMPTOMS GET VISIBLE IN THE PLANT WITH B CONCENTRATION IN LEAVES > 100 µG/KG –

MIYASAKA ET AL. (1999)

Over aplication of Boron leads to toxicity symptoms 350

Dry weight of new leaves (g) Boron toxicity symptoms visible 35

*

300 Foliar B (mg/kg)

250

*

*

30 25

200

20

150

15

100

10

50

5

0

0 0

3,7

11

22

44

89

178

Added B (mg/kg soil fines)

Over application led to chlorosis symptoms, necrotic spots and a depression of vegetative growth Source: Miyasaka et al (1999)

Dry weight of new leaves (g)

Foliar B (mg/kg)

Over supply of Boron leads to toxicity symptoms Foliar B (mg/kg)

Deformed leaves (%)

350

17,5

300

15

250

12,5

200

10

150

7,5

Plants ok

100 50

5 Boron deficiency symptoms visible

Deformed leaves (%)

Foliar B (mg/kg)

Boron toxicity symptoms visible

2,5

0

0 0

1

10

100

B level in solution (µm)

Deficiency leads to deformed leaves plus “shot-holes” in the leaves Toxicity leads to interveinal chlorosis and necrosis Source: Miyasaka et al (1999)

Copper deficiency

Leaf is deformed and cups up

Iron deficiency

Veins remain dark green

Manganese deficiency

Interveinal yellowing with brown necrotic spots

Nutrition of Avocado Zinc

Application of Zn increases leaf Zn status Foliar Zn conc (µg/g)

1992 - Start

1993

1994

120 100 80 60 40 20 0 ZnSO4 soil

ZnSO4 irrigation

Zinc-sulfate was soil banded and through the irrigation system applied. Variety: Hass, commercial orchard, California All trees had a leaf Zn concentration < 50µg/g at the beginning; grown on calcareous soils Source: Crowley et al. (1996)

Application of Zn increases leaf Zn status Foliar Zn conc (µg/g)

June

July

August

September

October

100 80 60 40 20 0 Control

ZnSO4 via soil

Zinc-sulfate was soil applied (3.2 kg ZNSO4/tree = 1.14 kg Zn/tree) in May. Variety: Hass, commercial orchard, California All trees had a leaf Zn concentration < 50µg/g at the beginning; grown on Calcareous soils

Source: Crowley et al. (1991) – from Hofshi (2001)

Zinc 

DEFICIENCY SYMPTOMS – – –

INTERVEINAL YELLOWING (MOTTLED LEAVES) SHORTENED INTERNODES DEFORMED (ROUND) AND SMALLER FRUITS



DEFICIENCY OCCURS AT LEAF ZINC CONCENTRATIONS < 20 MG/KG



OPTIMUM LEAF ZINC CONCENTRATION –



30-150 MG/KG IN MATURE SUMMER FLUSH LEAVES, BEFORE INFLORESCENCE

OCCURS MAINLY IN CALCAREOUS SOILS

Source: Crowley et al., 1991; Hofshi, 2001

Zinc deficiency

Zinc deficiency

Nutrition of Avocado Other effects

Salt toxicity

Chloride toxicity Sodium toxicity

Nutrition of Avocado Analysis

Leaf Sampling in Avocado (Southern Hemisphere) 

  



For nutrient monitoring sample in March-April to coincide with cessation of the season's growth. Sampling Time: April to May, when the summer flush has ceased. Plant Part: 2nd - 4th leaf from the terminal bud (blade plus petiole). Collect From: Shoots that are not flushing nor fruiting. Select at shoulder height - exclude boundary trees. Quantity per Sample: 4-8 leaves from each of 20 trees selected at random. Ring of buds between the previous and present year´s growth

Source: National department of agriculture, South Africa Koen & du Plessis (1992)

Leaf Analysis Standards – various Countries Unit %

Australia 2.2 - 2.6

California 2.2 - 2.4

New Zealand 2.2 - 2.6

South Africa 2.2 - 2.4

Mexico 2.2 - 2.6

Phosphorus

%

0.08 - 0.25

0.08 - 0.44

0.08 - 0.25

0.08 - 0.15

0.08 - 0.25

Potassium

%

0.75 - 2.0

1.0 - 3.0

0.8 - 2.0

0.75 - 1.25

0.71 - 2.0

Calcium

%

1.0 - 3.0

1.0 - 4.5

1.0 - 3.0

1.0 - 2.0

1.0 - 3.0

Magnesium

%

0.25 - 0.8

0.25 - 1.0

0.25 - 0.8

0.4 - 0.8

0.25 - 0.8

Sulphur

%

0.2 - 0.6

0.2 - 0.6

0.2 - 0.6

0,2- 0,6

0.2 - 0.6

Sodium

%

> 0.25

> 0.25

> 0.25

> 0.25

Chlorine

%

> 0.25

> 0.25

> 0.25

> 0.25

Boron

ppm

40 - 60

12 - 100

35 - 80

50 - 80

50 - 100

Copper

ppm

5 - 15

5 - 15

5 - 15

5 - 15

5 - 15

Iron

ppm

50 - 200

50 - 300

50 - 200

50 - 150

50 - 200

Manganese

ppm

30 - 500

30 - 700

30 - 500

30 - 250

30 - 500

Zinc

ppm

40 - 80

30 - 250

30 - 150

30 - 100

30 - 150

Nitrogen

University of California DANR Analytical Lab

Right Nutrition at the right time 

The fruit Size of avocado is higher related to the number of cells than to the cell size in fruits –



It is important to maximize cell division in fruit during the first 7-8 weeks after fruit set –



Moore-Gordon et al. 1997

Cowan et al 1997, 2001

The two key trace elements involved in this process are Zinc and Boron.

Source: Wolstenholme, 2001; Whiley, 2001_b