Agronomic Services

Crop Fertilization Based on North Carolina Soil Tests

Table 4.6  Fertilizer dilutions necessary (oz/100 gal. water) to deliver parts-per-million (ppm) rates *
ppm soln.	Percent Element in Fertilizer
	10	13	15	16	18	20	25	30	33.5	46	50
50	6.7	5.1	4.4	4.2	3.7	3.3	2.7	2.2	2.0	1.5	1.3
100	13.3	10.3	8.9	8.3	7.4	6.7	5.3	4.4	4.0	2.9	2.7
125	16.6	12.8	11.1	10.4	9.3	8.3	6.7	5.6	5.0	3.6	3.3
150	20.0	15.4	13.3	12.5	11.1	10.0	8.0	6.7	6.0	4.3	4.0
175	23.3	17.9	15.6	14.6	13.0	11.7	9.3	7.8	7.0	5.1	4.7
200	26.7	20.5	17.8	16.7	14.8	13.3	10.7	8.9	8.0	5.8	5.3
250	33.3	25.6	22.2	20.8	18.5	16.7	13.3	11.1	10.0	7.2	6.7
300	40.0	30.8	26.7	25.0	22.2	20.0	16.0	13.3	11.9	8.7	8.0
350	46.7	35.9	31.1	29.2	25.9	23.3	18.7	15.6	13.9	10.1	9.3
400	53.3	41.0	35.6	33.3	29.6	26.7	21.3	17.8	15.9	11.6	10.7
450	60.0	46.2	40.0	37.5	33.3	30.0	24.0	20.0	17.9	13.0	12.0
* Equivalent units: 1.0 lb = 454 g = 16 oz; 1.0 oz = 28.38 g. The equation for calculating the amount of fertilizer to mix in 100 gallons of water is shown below:                       ppm of desired element ÷ percent of element × 0.75 = oz/100 gal.
Hardy DH, Tucker MR, Stokes CE. 2013. Crop fertilization based on North Carolina soil tests. Raleigh (NC): North Carolina Department of Agriculture and Consumer Services, Agronomic Division. Circular No. 1.