Vegetables
Proper fertilizing is crucial in growing vegetables. Proper nitrogen dose should be determined with taking into account its impact on nitrate content in production and possible groundwater contamination. Doses exceeding 120 kg N/ha should be split into parts. The main dose of nitrogen should be applied prior to sowing seeds or planting seedlings, the remainin part for top dressing. In growing of plants sensitive to salinity single dose of nitrogen in a prevegetation period should not exceed 100 kg N/ha on light soils and 150-200 kg N/ha on medium and heave soils. Plants less sensititve on light soils it is allowed to apply in one part 200 kg N/ha and on heavy soils up to 300 kg N/ha. The highest sensitivity of plants to phosphorus deficiency in soil is in primary period of vegetation. Phosphoric fertilizers should be applied prior to sowing.
Taking into consideration high uptake of potassium by vegetables, their fertilizing with this nutrient needs a special attention. A lot of vegetables tolerate higher content of chlorine in soil. Less tolerant vegetables can be fertilized with sulphate fertilizers. They are however more expensive and lead to growing concentrations of nitrates in plant production. Some plants gather high volumes of nitrates (leaf vegetables, roots, cabbages). Therefore it is recommended to apply 60% of potassium chloride. In case the vegetables do not tolerate higher chlorine content in soil, they automatically gather excessive volumes of nitrates. It is therefore recommended to apply potassium chloride a few weeks prior to sowing. Potassium fertilizing is done usually in Autumn, which allows precise mixing of K with soil and leaching of chloride to lower soil layers. Doses of potassium exceeding 150 kg K2O/ha it is recommended to split the dose into Autumn dose (prior to winter plowing) and Spring dose (prior to sowing)
Indicative doses of N, P, K in growing of vegetables (E. Szwonek, Research Institute of Pomology and Floriculture):
| N | P2O5 | K2O | |
|---|---|---|---|
| Brussels sprouts | 150-200 | 70-120 | 200-250 |
| Cauliflower | 150-250 | 70-90 | 200-240 |
| Early cabbage | 90-100 | 70-80 | 200-240 |
| Late cabbage | 150-200 | 90-100 | 240-300 |
| Cucumber | 100-120 | 70-80 | 200-250 |
| Early carrot | 80-130 | 60-70 | 180-230 |
| Late carrot | 140-200 | 70-80 | 200-270 |
| Parsley | 80-150 | 50-60 | 180-250 |
| Leeks | 100-160 | 60-90 | 130-180 |
| Onion | 100-140 | 70-80 | 150-200 |
| Tomato | 80-150 | 50-70 | 140-190 |
| Celery | 150-200 | 50-100 | 190-300 |
| Broad beans | 50-60 | 60-80 | 130-160 |
| Green beans | 30-50 | 60-80 | 140-160 |