HortFACT - Carnations - Plant Analysis - Nutrient Testing of Leaves
Production of greenhouse carnations, both for export and local supply, is an important component of the floriculture industry in New Zealand, although export volumes have steadily declined over the last 6 years. Techniques and management vary, but in order to achieve optimum production, carnations need a nutrient supply adapted to suit their needs. Plant analysis can help in supplying valuable information as to their nutritional requirements.
Nutrients are supplied via the growing medium and by regular fertiliser application based on the plant requirements. Hence, a knowledge of the response of the crop to certain inputs is needed. Remember also, that when dealing with this type of crop, yield is not the prime factor, but needs to be considered along with the quality and economics of the crop.
Plant analysis can assess the concentration of various nutrients in the plant, and for the purpose of this Hortfact, we regard the status of the leaves as an indicator of the nutrient status of the whole plant.
If the concentration in the leaves is matched with recorded crop performance, valuable information is obtained which can be kept on file and used to evaluate nutrient supply to future crops. In doing this, it is necessary to consider other growth-controlling factors, such as light, temperature and general crop health.
In many laboratories around NZ, a plant analysis service has been provided for a number of years. The concentrations for the thirteen elements presented in this Hortfact are based on the distribution of values obtained and on the experience of horticultural advisory officers.
Select sixty leaves representative of plants throughout the growing unit. Samples should be of the youngest mature leaves - 5th or 6th leaf from the top of the lateral growths. Ideally, samples should not be taken from a flowering lateral. If this is not possible, flower buds should be small.
Varieties should be kept separate as far as possible and diseased or damaged tissue avoided. Samples should also be clean.
Spray residues are impossible to remove and they will give high analytical results. It is therefore important that details of any recently-used sprays are included with the sample details.
Experience points to levels of N and K around 4.0% as most favourable. Rather than trying to fit all crops into these guidelines, it is more valuable to analyse crops routinely and gauge performance at each set of figures. Do not forget to note other factors which may have influenced performance for each set of data. This will avoid comparisons between crops subject to different techniques, management and growing situations.
Table 1: Nutrient levels in the leaves of greenhouse carnations
| Nutrient | Deficient | Low | Optimum | High | Excess |
|
Nitrogen
(% N) | <2.45 | 2.46-3.32 | 3.33-4.19 | 4.20-5.06 | >5.07 |
|
Sulphur
(% S) | <0.17 | 0.18-0.26 | 0.27-0.35 | 0.36-0.44 | >0.45 |
|
Phosphorus
(% P) | <0.11 | 0.12-0.25 | 026-0.40 | 0.41-0.52 | >0.53 |
|
Magnesium
(% Mg) | <0.18 | 0.19-0.28 | 0.29-0.39 | 0.40-0.49 | >0 50 |
|
Calcium
(% Ca) | <0.60 | 0.61-1.12 | 1.13-1.64 | 1.65-2.15 | >2.16 |
|
Sodium
(% Na) | – | – | 0.10-0.50 | – | – |
|
Potassium
(% K) | <1.89 | 1.90-2.78 | 2.79-4.00 | 4.01-4.50 | >4.51 |
|
Manganese
(Mn ppm) | <19 | 20-49 | 50-250 | 251-400 | >401 |
|
Zinc
(Zn ppm) | <15 | 15-19 | 20-60 | 61-100 | >101 |
|
Copper
(Cu ppm) | <2 | 3-5 | 6-10 | 11-30 | >31 |
|
Boron
(B ppm) | <19 | 20-29 | 30-100 | 101-200 | >201 |
|
Molybdenum
(Mo ppm) | – | <0.09 | 0.10-2.10 | 2.11 | – |
|
Iron
(Fe ppm) | <39 | 40-50 | 51-120 | 121 | – |
Langhans (ed.), 1961: Carnations - a Manual of the Culture, Insects and Diseases, and Economics of Carnations.
See also:
Carnations - Pre-planting for Commercial Production
Carnations - Harvesting and Post Harvest Practices for Commercial Production
Prepared for HortNET - June 1998