• LEGUMINOSEAE (broad beans, peas, French beans, runner beans)
• CRUCIFERAE (cabbage, cauliflower, brussel sprouts, turnip, swede, radish)
• CUCURBITACEAE (squash, pumpkins, melons, cucumbers, courgettes)
• AMARYLIDICEAE (leeks, onions, garlic)
• CHENOPODACEAE (red beet, spinach, silverbeet)
• COMPOSITAE (lettuce)
• UMBELLIFERAE (carrots, parsnips, celery)
• SOLONACEAE (tomatoes, potatoes, sweet peppers, aubergines)
• GRAMINACEAE (Sweetcorn)
• LILIACEAE (Asparagus)
• Soil Target Levels for Phosphate (Olsen P)
• Soil Target Levels for Potassium (MAF Quick-test Units)
• FURTHER READING

Nitrogen requirements are the total requirement for the crop; the actual fertiliser requirement is influenced by the N supplying power of the soil. This depends on soil type, cropping history and climate and is difficult to quantify. British work suggests that soils which were previously cropped with legumes, have been recently plowed out of pasture or have received moderate dressings of organic manures can supply the equivalent of 50 kg/ha fertiliser N, while frequent heavy applications of organic manures or a lucerne crop can contribute up to 100 kg N/ha. The N supplying power of land frequently cropped with cereals or non-leguminous vegetables can probably be discounted when calculating N fertiliser requirements.

Optimum Olsen P and soil K values are given for each crop in standard MAF Quicktest units. The amounts of P and K fertilisers required to modify soil test values are in Tables 1 and 2.

The amount of nutrients absorbed from the soil are given for each crop, together with estimates of the amounts removed in produce, where data is available. Total uptake figures give a relative estimate of the overall nutrient requirements of a crop, although crops also vary in the efficiency with which they can absorb nutrients from the soil. Product removal values indicate the minimum amount of nutrients which must be replenished with fertilisers if soil fertility is not to decline. It must be remembered however that nutrient removal in produce is not the only source of nutrient loss from the soil. Leaching and fixation can be of equal importance.

Some of the nutrient removal data is based on recent trial work. Where the trial yields are significantly higher than normal commercial yields, the nutrient removal data can be reduced proportionately.

Commonly occurring nutrient concentrations in vegetable tissues are listed in the Appendix. It is important to recognise that while these may be characteristic values, values outside of these ranges do not automatically imply deficiencies or excesses.

Critical concentrations of NPK at various stages of growth are given for some species. They are derived from data given by Scaife and Turner (1983). They indicate minimum desirable nutrient concentrations in whole plant tops and demonstrate the marked changes in values which occur as plants develop; they also emphasise the need to consider plant age and development when interpreting tissue analysis data.

Deficiency symptoms are listed under each species when they either differ from the generalised symptoms for a particular element, such as the purpose colouration of N deficient Brassica leaves, or when they are unique to a particular species or family of vegetables, such as whiptail in Mo deficient cauliflowers. Many of these descriptions are taken from Scaife and Turner (1983), which should be consulted for photograhs of deficiency symptoms.

LEGUMINOSEAE (broad beans, peas, French beans, runner beans)

Nutrient requirements

Total nitrogen (kg/ha):

Target Olsen P values:

Method of P application: Broadcast, and banded

Target K values:

Method of K application: Broadcast

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix.

Critical N, P and k concentrations (%) in whole plant tops:

Desirable N concentrations in youngest mature leaves (Levin):

Specific deficiency symptoms

CRUCIFERAE (cabbage, cauliflower, brussel sprouts, turnip, swede, radish)

Nutrient requirements

Total nitrogen (kg/ha):

Target Olsen P values:

Method of P application: Banded for all except radish, swedes and turnips.

Target K values:

Method of K application: Banded for all except radish, swedes and turnips.

Optimum pH range:

Note that clubroot infection is diminished at pH greater than 6.5.

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix. In the tabulated information on critical concentrations that follows, the plant age (days) refers either to the number of days after transplanting, or to the number of days from emergence for crops that are directly seeded. Critical N, P and K concentrations (%) in whole plants:

Desirable N concentration in youngest mature leaves (Levin):

Specific deficiency symptoms

CUCURBITACEAE (squash, pumpkins, melons, cucumbers, courgettes)

Nutrient requirements

As with many vegetables, nutrition during the first 2-3 weeks after emergence has a major effect on the final yields. Work from Pukekohe is included in this section; this indicates greater requirements for P and K for squash than earlier work.

Total nitrogen (kg/ha):

Data from Pukekohe shows that maximum yields of squash were obtained with an Olsen test value of 130 on Patumahoe clay loam, suggesting that these target values are minimal.

Method of applying P fertilisers: Banded.

Target K values:

Maximum yields were obtained with a soil K value of 17 on Patumahoe clay loam at Pukekohe.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Concentrations of nutrients commonly found in Cucurbit leaves are in the Appendix. It is important to note that while these are characteristic values, concentrations outside the ranges given do not automatically imply deficiencies or excesses.

Desirable N concentration in youngest mature leaves (Levin):

Specific deficiency symptoms

AMARYLIDICEAE (leeks, onions, garlic)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Broadcast.

Target K values:

Method of K application: Broadcast.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix.

Critical N, P and K concentrations (%) in whole plants:

Specific deficiency symptoms

CHENOPODACEAE (red beet, spinach, silverbeet)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Broadcast.

Target K values:

Method of K application: Broadcast.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring values are in the Appendix.

Critical N, P and K concentrations (%) in whole plants:

Specific deficiency symptoms

COMPOSITAE (lettuce)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Broadcast.

Target K values:

Method of K application: Broadcast; sulphate of potash preferred because of sensitivity to excess chloride.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring values are in the Appendix.

Critical N, P and K concentrations (%) in whole plants:

Specific deficiency symptoms

UMBELLIFERAE (carrots, parsnips, celery)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Broadcast.

Target K values:

Method of K application: Broadcast.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix.

Critical N, P and K concentrations (%) in whole plants:

Desirable N concentrations in youngest mature leaves (Levin):

Specific deficiency symptoms

SOLONACEAE (tomatoes, potatoes, sweet peppers, aubergines)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Potatoes banded, tomatoes broadcast.

Target K values:

Method of K application: Potatoes banded, tomatoes broadcast.

Note that tomatoes are susceptible to chloride toxicity so that potassium sulphate is the preferred form.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix.

Desirable N concentrations in youngest mature leaves (Levin):

Specific deficiency symptoms

GRAMINACEAE (Sweetcorn)

Nutrient requirements

(See also Cornforth and Sinclair (1984) for nutrient requirements of maize).

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Banded.

Target K values:

Method of K application: Banded.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring but not critical values are in the Appendix.

Desirable N concentrations in stems (Levin):

Specific deficiency symptoms

LILIACEAE (Asparagus)

Nutrient requirements

Total nitrogen (kg N/ha):

Target Olsen P values:

Method of P application: Broadcast.

Target K values:

Method of K application: Broadcast.

Optimum pH range:

Nutrient uptake (kg/ha)

Tissue analysis

Commonly occurring, but not critical values are in the Appendix.

Soil Target Levels for Phosphate (Olsen P)

Soil Target Levels for Potassium (MAF Quick-test Units)

FURTHER READING

Bergman, W. (1992). Nutritional Disorders of Plants. Gustav Fischer Verlag Jena, New York. p.386.

Franklin, S.J. (Editor) (1990). The New Zealand Asparagus Manual. The NZ Asparagus Council, PO Box 74-107, Auckland, New Zealand. Section 4.0.

Lorenz, O.A. and Maynard, D.N. (1988). Knott's Handbook for Vegetable Growers. A. Wiley Interscience Publications, New York. pp390.

Cornforth, I.S. and Sinclair, A.G. (1984). Fertiliser and Liming Recommendations for Pastures and Crops in New Zealand. Second Revised Edition. New Zealand Ministry of Agriculture and Fisheries, Wellington. pp76.

Scaife, A. and Turner, M. (1983). Diagnosis of Mineral Disorders in Plants. Vol. 2. Vegetables. (Robinson, J.B.D., Ed), HMSO, London. pp96.