Crop Guide: Nutritional recommendations for Cucumber - Haifa-Group

Nutrient Uptake (kg/ha)
1000
800
600
400
200
0
300
greenhouse
30-50
open-field
Figure 3.11: N-P-K uptake rates by cucumber crops at various growing conditions and yields.
Table 3.5: Indicative N-P-K ratios at various growing conditions (La Malfa, 1992)
Open Field Greenhouse
Expected yield (Ton/ha) 15 – 30 120 - 300
Typical N:P:K ratio 1:0.5:1.5 1:0.5:2
High concentrations of K are found in various plant parts, and serve as a method to assess crop
nutritional status. On a whole organ basis, potassium is generally equally distributed between roots
and shoots.
Table 3.6: Leaf analysis potassium standards for field-grown cucumbers (in dry matter of youngest
fully mature leaf with petiole taken at early flowering stage).
Nutrient Unit Deficient Low Normal High Excessive
Potassium (K) % 5.0
Normal levels in petiole sap are 3,500 – 5,000 ppm K.
Yield (ton/ha)
The accumulation of K in stems, petioles and leaves correlates with the growth curve of these
organs; this suggests a mechanism that balances K uptake and release. K accumulates rapidly in
each leaf during its early developmental stage (Figure 3.12). The overall demand of the plant leaves
creates therefore a sigmoid ascending curve.
32
30
open-field
N
P2O5
K20
15
open-field