Fertilizer Requirements of Cereals

The total amount of plant nutrients removed from the soil by a crop depends on the yield - the greater the yield, the greater the amount removed.

Based on equal seed yields per unit area, whole barley, wheat and oat plants extract about the same combined quantities of nitrogen (N), phosphorus (P₂O₅), potassium (K₂0) and sulphur (S) from the soil, but considerably less than canola. When only the seed is removed, and all straw is left on the field, barley removes slightly more nutrients from the soil than oats but less than wheat or canola as the following table shows.

Nutrients Used by Crops* (kilogram per hectare)

Crop	Crop Part	N	P₂0₅	K₂0	S

Wheat	Seed	79	32	21	5
(3225 kg/ha or 48 bu/ac)	Straw	32	7	64	8
	Total	111	39	85	13

Barley	Seed	65	24	22	5
(3225 kg/ha or 60 bu/ac)	Straw	34	9	73	8
	Total	99	33	95	13

Oats	Seed	58	24	17	8
(3225 kg/ha or 84 bu/ac)	Straw	40	15	70	10
	Total	98	39	87	18

Canola	Seed	120	57	29	21
(3225 kg/ha or 57 bu/ac)	Straw	70	26	121	17
	Total	190	83	150	38
(To convert kg/ha into lb/ac, multiply by 0.89) Canola yield is extremely high, but in order to make the comparison, it was left at the same weight as the other grains.
*Source: Western Canada Fertilizer Association.

For more information about the content of this document, contact Len Kryzanowski.
This document is maintained by Mary Ann Nelson.
This information published to the web on July 17, 2002.
Last Reviewed/Revised on January 20, 2015.