Agronomic Services

Crop Fertilization Based on North Carolina Soil Tests

Table 1.3  Manganese availability indices (Mn-AI) forcrops less sensitive to manganese*
Soil pH	Manganese Index from Soil Test Report
	5	10	15	20	25	30	35	40	45	50
5.4	29	32	35	38	41	44	47	50	53	56
5.5	28	31	34	37	40	43	46	49	52	55
5.6	26	29	32	35	38	41	44	47	50	53
5.7	25	28	31	34	37	40	42	45	48	52
5.8	23	26	29	32	35	38	41	44	47	50
5.9	22	25	28	31	34	37	40	43	46	49
6.0	20	23	26	29	32	35	38	41	44	47
6.1	19	22	25	28	31	34	37	40	43	46
6.2	17	20	23	26	29	32	35	38	41	44
6.3	15	18	21	24	27	30	33	36	39	42
6.4	14	17	20	23	26	29	32	35	38	41
6.5	12	15	18	21	24	27	30	33	36	39
6.6	11	14	17	20	23	26	29	32	35	38
6.7	9	12	15	18	21	24	27	30	33	36
6.8	8	11	14	17	20	23	26	29	32	35
6.9	6	9	12	15	18	21	24	27	30	33
7.0	5	8	11	14	17	20	23	26	29	32
* Mn-AI is calculated based on equation B  [108.2 + 0.6 Mn-I –15.2 pH]  and rounded to the nearest whole number. The critical Mn-AI = 25. Crops less sensitive to manganese include asparagus, beets, blueberries, Christmas trees, corn, forage grasses and legumes, pearl millet, milo, okra, irish potatoes, raspberry, rhubarb, rice, sorghum, sunflower, sweetpotatoes, and commercial nursery and flower crops.
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.