Diversification of rice growing areas in Eastern India with integrated soil–crop system management for GHGs mitigation and higher productivity

Figures & data

Figure 1. Study location in Nadia and North 24 Parganas district of West Bengal (India).

Figure 2. Intercropping of pumpkin with rice (SRI) under ILM_soil system. A: After 15 days of Transplantation; B: At maturity stage of rice.

Table 1. Crop management including annual application of manure and fertilizer under different soil management treatments.

Treatment	N (kg ha^−1)		P (kg ha^−1)	K (kg ha^−1)	Manure (kg ha^−1)	Cultivar	Inter/ mixed crop (cultivar)	Density (plant m^−2)	Sowing /Transplanting month	Weeding	Residue Management
	Basal	Top dressing
ILMsoil
Jute	20	50	30	40	2000	NJ 7010	Green Gram (cv. TMB37)	50–60	25–30 Mar	Mechanical	Return
Rice	30	30	30	30	2000	Khitish	Pumpkin (cv. Bravo)	25	5–10 Aug (SRI)	Mechanical	Return
Mustard	25	25	40	40	1000	B-9	Lentil (cv. WBL58)		10–15 Dec	Manual	Return
IMsoil
Jute	50	40	50	50	1000	JRO 204	–	50–60	5–10 Apr	Mechanical	Remove
Rice	40	40	40	40	1000	Pratikshya	–	54	5–10 Aug	Manual	Remove
Mustard	30	30	50	40	500	B-9	–		10–15 Dec	Manual	Remove
CMsoil
Jute	30	30	40	35	750	JRO 524	–	90–100	5–10 Apr	Manual	Remove
Rice	55	40	40	40	750	IET 4094	–	54	10–15 Aug	Manual	Remove
Mustard	15	15	40	40	500	B-9	–		15–20 Dec	Manual	Remove

ILM_soil: Integrated soil-crop Management; IM_soil: Improved management; CM_soil: Conventional management; SRI: System of rice intensification. Return: biomass of weeds and intercrops after harvesting of pulse and pumpkin mixed in the soil; Remove: removal of weeds from cultivated field without mixing in soil.

Table 2. Greenhouse gas (GHG) emission coefficient of farm inputs used in the study.

Input	Unit	GHG coefficient (kg CO2-eq ha^−1)	Data source/Reference
Mouldboard ploughing	MJ	15.2	[48]
Field cultivation	MJ	4.0	[25]
Seed sowing	MJ	3.20	[25]
Machinery	MJ	0.071	[49]
Diesel fuel	L	2.76	[50]
Manure	kg	0.0032	[25]
Nitrogen (N) fertilizer	kg	1.30	[25,51]
Phosphorus (P2O5) fertilizer	kg	0.20	[25,51]
Potassium (K2O) fertilizer	kg	0.20	[25,51]
Herbicide	kg	6.30	[25,51]
Insecticide	kg	5.10	[25,51]
Fungicide	kg	3.90	[25,51]
Water for irrigation	mm	0.05	[25]
Harvesting	MJ	10	[25]

Table 3. Change in soil nutrient content during the experimental three-year period (2018–2020).

Soil parameters	Initial	Soil characteristics* (0–30 cm)
		2018			2019			2020
		ILM	IM	CM	ILM	IM	CM	ILM	IM	CM
pH	7.72^a	7.38^b	7.73^a	7.48^a	6.70^c	7.77^a	7.41^a	6.84^c	7.52^a	7.28^a
Org C (g kg^−1)	4.40^a	4.80^b	4.60^a	4.10^a	5.80^c	4.90^a	4.20^a	7.10^c	5.10^a	4.70^a
Avail. N (kg ha^−1)	178^a	201^c	184^a	174^a	214^c	184^a	164^a	247^c	184^a	169^a
Avail. P2O5 (kg ha^−1)	52.60^a	40.81^b	54.14^a	49.7 1^a	43.64^b	57.18^a	49.22^a	43.96^b	56.27^a	53.31^a
Avail. K2O (kg ha^−1)	75.27^a	89.85^b	77.86^a	69.3^a	105.48^c	80.21^a	81.03^a	121.61^c	83.66^a	77.86^a

* Mean values followed by a common letter are not significantly different by DMRT at 5% level.

Table 4. Production, economics, carbon sequestration, water productivity and nitrogen use efficiency under ILM_soil, IM _soil and CM_soil system.

Treatment	Yield (kg ha^−1)	EY (kg ha^−1)	LER	CC (US$)	BCR	Total water use (mm)	WP** (kg ha^−1 mm^−1)	N-applied (kg ha^−1)	NUE* (kg grain or fibre kg^−1 N added)
Rice grain
ILMsoil	4920	9050	2.26	462*	3.17	861.1	5.74^c	60.00	83.20^c
IMsoil	3755	3755	1.00	289	2.56	682.2	5.56^a	80.00	47.30^a
CMsoil	3300	3300	1.00	276	2.36	785.7	4.22^b	95.00	35.45^b
Mustard seeds
ILMsoil	960	1231	1.19	239*	2.71	152.3	6.35^a	50.00	19.20^d
IMsoil	740	740	1.00	223	1.74	162.2	4.55^b	60.00	12.40^e
CMsoil	607	607	1.00	213	1.50	171.1	3.57^d	30.00	20.30^d
Jute fibre
ILMsoil	3216	3733	1.10	889*	2.04	540.5	5.96^a	75.00	42.80^a
IMsoil	2796	2796	1.00	912	1.49	578.3	4.85^b	90.00	31.10^b
CMsoil	2174	2174	1.00	901	1.17	389.8	5.60^c	60.00	36.20^b

EY: Equivalent yield; LER: Land equivalent ratio; CC: Cost of cultivation; BCR: Benefit:Cost ratio; WP: Water productivity.

* Cost of cultivation and B/C ratio of main crop plus inter/mixed crops; **Mean values followed by a common letter are not significantly different by DMRT at 5% level.

Figure 3. On-farm life cycle greenhouse gas emissions produced per season per hectare for rice-mustard-jute crop rotations with and without intercrops as influenced by integrated soil-crop management (ILM_soil), improved management with optimized crop and nutrient procedures (IM_soil), and conventional system (CMsoil) (p < 0.05).

Figure 4. SOC sequestration, average total (LCA-GHG) and net life cycle greenhouse gas emitted for the production of per hectare area in the rice-mustard-jute crop rotations with and without intercrops as influenced by integrated soil-crop management (ILM_soil), improved management with optimized crop and nutrient procedures (IM_soil), and conventional system (CM_soil) (p < 0.05).

Table 5. CO₂-eq emissions during cultivation and processing including labour use in the study.

Farm activities*	kg CO2-eq tonne^−1 of crop yield per hectare
	Jute			Rice			Mustard			Total
	ILM	IM	CM	ILM	IM	CM	ILM	IM	CM	ILM	IM	CM
Cultivation	271	279	198	289	305	294	188	203	154	748	787	646
Processing	316	289	215	540	422	346	91	78	61	947	789	622
Labour	556	676	676	540	540	540	380	380	380	1476	1596	1596
Total	1143	1244	1089	1369	1267	1180	659	661	595	3171	3172	2864

* Cultivation: land preparation, ploughing, seed sowing, weeding, machinery and fuel used for ploughing and transportation, manure, fertilizer and pesticides application, irrigation and harvesting; Processing: extraction of fibre, threshing of paddy, green gram, mustard and lentil. Labour: sowing, farm input application, weeding, threshing, harvesting and drying.

Figure 5. Carbon based sustainability index (Cs) in the rice-mustard-jute crop rotations with and without intercrops as influenced by integrated soil-crop management practices.

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Data availability statement

The data used to support the findings of this study are available from the corresponding author upon request.