Removal of Nutrients from the Soil

Table 4 lists amounts of certain nutrient elements that are removed by vegetable crops. It includes both the amounts removed by harvest and those that remain in crop residue and are returned to the soil. These figures for crop removal should be considered approximate. They can be used as a basis for adjusting your own application rates up or down on a trial basis. Keep in mind that nutrient removal varies with factors such as soil moisture, temperature, and pH. Plants can absorb large amounts of a nutrient if it is in abundance; but this may not increase yield. Excess levels of some nutrients can reduce the yield and/or quality of some crops.

Nutrients that are relatively immobile in the soil, such as phosphorus, calcium, magnesium and the micronutrients, are not all extracted by plants because the roots do not come in contact with all of the nutrients. This is especially true of certain vegetables that have small or sparse root systems. Most of the phosphorous applied to the soil becomes fixed in a form unavailable to plants. Thus, it is necessary to provide some excess amounts of nutrients when soil test levels are below the optimum range, and this is why rates sufficient to replace the amount removed by crops are sometimes recommended for soils that test in the optimum range.

Table 4: Approximate Nutrient Removal by Selected Vegetable Crops.

Vegetable		Yield per acre¹	Nutrient removal, lbs/acre
Vegetable		Yield per acre¹	N	P₂O₅	K₂O	Ca	Mg
Snap beans	Total	250 bu	30	20	35	7	3
Broccoli	Heads	5 tons	20	2	45
	Other		145	8	165
	Total
Cabbage	Total	20 tons	125	30	130	28	10
Carrots	Roots	25 tons	80	20	200
	Tops		65	5	145
	Total		145	25	345
Cauliflower	Total	6 tons	45	18	43	4	3
Celery	Tops	50 tons	170		380
	Roots		25		55
	Total		195	80	435	110	27
Cucumbers	Total	24 tons	100-200	33-72	100-400
Eggplant	Total	16 tons	207	46	34
Kale	Total	10 tons	125	30	110	50	10
Lettuce	Total	15 tons	75	35	150	13	5
Muskmelons	Fruit	11 tons	95	17	120
	Vines		60	8	30
	Total		155	25	150
Onions	Bulbs	20 tons	110	20	110	12	14
	Tops		35	5	45
	Total		145	25	155
Peppers	Total	12 tons	137	52	217
Potatoes, White	Tubers	300 cwt	90	45	160
	Vines		60	20	60
	Total		150	65	220
Potatoes, Sweet	Roots	15 tons	75	55	160
	Vines		35	5	280
	Total		110	60	440	10	15
Spinach	Total	10 tons	100	25	100	24	10
Squash, Summer	Total	10 tons	32	12	56
Squash, Winter	Total	6 tons	12	10	58
Sweet Corn	Ears	250 cr.	55	8	30
	Stalks		100	12	75
	Total		155	20	105
Tomatoes	Fruit	30 tons	110	48	180	15	15
	Vines		90	30	100	24	21
	Total		200	78	280	39	36

¹ These are assumed yields. Actual yields may vary depending on weather and cultural practices. Adjust nutrient removal rates accordingly. To convert to volume or count yield units see Table 15: Approximate Yields.