Vegetable fertilisation – Dobre Praktyki Rolnicze

Vegetable plants have very diverse nutrient requirements. The aim should be to alternate between species with different needs. Directly cultivating species with high nutrient demands following each other can lead to excessive depletion of mineral nutrients from the soil. Mineral deficiency may not affect the entire soil profile but only individual layers. Therefore, to prevent the leaching of minerals into the deeper soil layers and make rational use of mineral nutrients, plants with deep and shallow root systems should be grown alternately. Vegetables with deep root systems include root vegetables, cabbages, kale, and tomatoes. Typical plants with an external root system are radishes, spinach, cucumbers, kohlrabi.

Plants with high nutritional demands are required to be grown on land where manure, compost, or legumes have been ploughed in. This is all about vegetables with very high requirements to nitrogen, which is a component significantly affecting the yield and at the same time easily leached into the soil profile (Table 1a).

Table 1a. Ranking of vegetable species by nitrogen requirements

Nitrogen requirements of vegetable crops*
High	Medium	Low
Cucumber, cauliflower, cabbages, courgettes, tomato, Brussels sprouts, celery, peppers, aubergines	Radishes, broccoli, kale, leek, beans, beetroot, kohlrabi, chicory, carrots, parsley	Lettuce, peas, mâche, asparagus, snap beans
* within each group, the plants are ranked from the most demanding

Fertilising vegetables in the field

The issue of nitrogen fertilisation assumes great importance in the cultivation of vegetables with high nitrogen fertilisers rates. Moreover, increasing the amount of available nitrogen can contribute to excessive nitrate accumulation in the plant. Standard nitrogen rates for field vegetable production are listed in Table 1.

Table 1. Optimum soil pH ranges and standard macronutrient contents of field vegetable crops

	mg dm ³						pH
	N	P	K	Ca	Mg	S-SO₄
Beetroot	700-100	50-70	175-250	1500-2000	60-80	20-40	6.0-7.5
Broccoli	100-120	50-60	170-200	1000-1500	50-60	20-40	6.2-7.0
Onion	100-150	60-80	175-250	1500-2000	60-80	20-40	6.5-7.8
Horseradish	50-130	40-60	175-225	1500-2000	60-80	20-40	5.5-6.7
Green beans	30-80	40-60	125-175	1000-2000	50-70	20-40	6.5-7.8
Peas	30-80	40-60	125-175	1000-2000	60-80	20-40	6.5-7.8
Cauliflower	100-140	50-70	160-220	1000-1500	50-80	20-40	6.4-7.5
White cabbage	100-140	50-70	160-210	800-1200	60-80	20-40	6.2-7.8
Brussels sprouts	100-120	60-80	190-220	1000-1500	60-80	20-40	6.2-7.8
Carrot	80-130	60-80	150-200	1500-2500	60-80	20-40	6.5-7.5
Cucumber	80-100	60-80	175-250	1500-2000	60-80	20-40	6.0-7.2
Parsley	60-80	40-60	150-250	1500-2000	70-80	20-40	6.5-7.5
Tomato	100-150	60-80	200-250	1200-1500	60-80	20-40	5.5-6.5
Leek	70-120	60-80	175-200	1000-1500	50-70	20-40	6.0-7.4
Rhubarb	100-150	60-80	175-200	1000-1500	60-80	20-40	5.5-6.5
Radish	30-80	40-60	120-150	1000-1500	60-80	20-40	6.0-7.4
Lettuce	30-80	50-70	150-200	1000-1500	60-80	20-40	6.0-7.5
Celery	100-130	60-80	200-250	1500-2500	60-80	20-40	6.5-7.5
Scorzonera	100-130	60-80	200-250	1500-2000	60-80	20-40	6.4-7.5
Asparagus	50-130	40-60	150-200	1500-2000	60-80	20-40	6.4-7.5
Spinach	30-80	50-70	175-250	1000-1500	60-80	20-40	6.0-7.5

Phosphorus fertilisation is adjusted in the fall or early spring by spreading fertilizer evenly over the crop surface and then mixing it into the soil. Phosphorus fertilisers should not be applied simultaneously as calcium fertilisers because the phosphorus will become depleted.

Potassium is taken up by the plant as K⁺ ions, mainly from the soil solution. An increased amount of potassium in the soil contributes to greater plant uptake and accumulation. Potassium is readily translocated within the plant. Standard soil potassium contents for different vegetable crops are shown in Table 1.

Note: Detailed rules for fertilising vegetables are given in the following study.

References: – “Zrównoważone nawożenie roślin ogrodniczych ” – A collective study edited by Dr. Paweł Wójcik – link to the publication – pdf