Impact of Indian Mustard (Brassica juncea) and Flax (Linum usitatissimum) Seed Meal Applications on Soil Carbon, Nitrogen, and Microbial Dynamics

Table 3

Soil carbon and nitrogen concentrations 51 d after amendment with various rates of flax or mustard oilseed meals or sorghum-sudangrass biomass.

Amendment rate (%)	Biomass type	Soil nutrient concentrations
		Total C; (g kg^−1 soil)	Organic C; (g kg^−1 soil)	Added organic; C remaining (%)	Total N; (g kg^−1 soil)	NH4-N; (mg kg^−1 soil)	NO3-N; (mg kg^−1 soil)
0.5	Unamended	12.95^a	5.77^a	—	0.90^a	2.33^a	37.67^a
	Flax	13.84^b	6.57^b	45.68^a	1.06^b	6.93^ab	147.20^b
	Mustard	13.33^ab	6.70^b	53.36^a	1.13^b	10.82^ab	161.83^b
	Sorghum-sudangrass	13.60^ab	6.96^b	71.13^a	0.82^a	16.82^b	9.73^c
1.0	Unamended	12.95^a	5.77^a	—	0.90^a	2.33^a	37.67^a
	Flax	14.42^ab	7.76^bc	47.12^ab	1.33^b	11.26^b	239.17^b
	Mustard	13.68^a	7.04^b	33.71^a	1.36^b	13.68^b	278.27^b
	Sorghum-sudangrass	16.52^b	8.00^c	60.20^b	1.15^ab	23.02^c	3.50^c
2.5	Unamended	12.95^a	5.77^a	—	0.90^a	2.33^a	37.67^a
	Flax	17.22^b	9.76^b	35.18^a	2.07^b	23.66^b	601.17^b
	Mustard	15.34^c	8.42^c	25.26^a	1.90^b	296.58^c	243.30^c
	Sorghum-sudangrass	19.24^d	21.60^d	67.44^b	1.16^c	5.52^a	3.03^d
5.0	Unamended	12.95^a	5.77^a	—	0.90^a	2.33^a	37.67^a
	Flax	23.30^b	16.57^bc	45.36^a	2.72^b	701.66^b	2.97^b
	Mustard	22.25^b	14.99^b	40.52^a	2.98^b	853.64^b	3.73^b
	Sorghum-sudangrass	25.18^b	19.34^c	65.45^b	1.46^a	4.93^c	2.83^b

Means within a column, for a given amendment rate (including the unamended control), followed by the same letter(s) are not significantly different at 𝑃<0.05.