Short-Term Response of Soil Organic Carbon Indices to Different Farming Strategies and Crop Rotation Systems in a Semiarid Warm Region

Table 1

Type and amount of organic/inorganic fertilizers and crop residues applied for three farming strategies: SIF_no-CR (standard rates of inorganic fertilizer, no return of crop residues to the soil), SOF_30% CR (standard rates of organic fertilizer, returning 30% of crop residues to the soil), and IOF_15% CR (integrated use of organic/inorganic fertilizers, returning 15% of crop residues to the soil) and four crops: mung bean (B), corn (C), sesame (S), and wheat (W) at the experimental plots implemented in Ahvaz, Khuzestan.

Farming strategy	Crop	Organic inputs		Inorganic fertilizer (kg ha^-1)
		Vermicompost + compost (t ha^-1)	Crop residues retention (g m^−2)	N-P-K
SIF_no-CR	B	—	Removed	30-50-50
	C	—	Removed	200-100-100
	S	—	Removed	75-50-50
	W	—	Removed	110-100-100
SOF_30% CR	B	3.3 + 10	228	—
	C	3.3 + 13.3	393	—
	S	3.3 + 10	129	—
	W	3.3 + 10	90	—
IOF_15% CR	B	1.7 + 5	114	15-25-25
	C	1.7 + 6.7	196.5	100-50-50
	S	1.7 + 5	64.5	32.5-25-25
	W	1.7 + 5	45	55-50-50
Physio-chemical properties	Compost	Vermi-compost	Crop residue
			B	C	S	W
Carbon (%)	58	65	48.5	49.5	47.5	48.5
Nitrogen (%)	1.84	2.18	3.3	6.63 × 10^−1	2.8	6.84 × 10^−1
C/N ratio	31.5	29.8	14.7	74.6	16.96	70.9
pH	7.35	5.38	—	—	—	—
EC (dS/m)	3.1	5.38	—	—	—	—
Moisture (%)	15	10	5	2	5	0