RESEARCH AND INNOVATION FOR ENHANCING WATER USE EFFICIENCY ENHANCING LAND USE AND WATER PRODUCTIVITY THROUGH ALTERNATE RAISED AND SUNKEN BEDS IN LOWLANDS OF BIHAR DR. VINOD KUMAR & DR. M P. SINGH
Rajendra Agricultural University, Pusa Samastipur (Bihar)
INTODUCTION
Low land rice area is mostly located in the eastern region and is about 14.4 million ha, which accounts 32.4 per cent of the total area under rice crop in India.
The average productivity of rice in low land areas ranges from 1.0 to 1.2 tonnes per ha as against the national average productivity of 1.9 tonnes per ha.
Shallow lowlands of Bihar comprising 1.6 lakh ha out of total 4.0 lakh ha waterlogged area, where the
root zone soil remains saturated or waterlogged
throughout the kharif as well as part of the rabi season.
In most of the cases the farmers are growing rice both in kharif and rabi seasons which alone is often not as remunerative to the areas where vegetables or other rabi crops are being taken.
In such lowlands, especially with shallow water inundation of less than 50 cm, modification in field topography through construction of alternate raised and sunken beds helps to improve the physical environment of the root zone and creates proper condition for the growth of aerobic crops(Singh et al., 2005).
Crop diversification is the need of the hour for better returns from the unit area to the farmers.
OBJECTIVES To study the effect of cropping system and irrigation under raised and sunken beds with different crops on: 1 2 3 4
Rice equivalent yield Net return Water productivity Land Use & suitability
MATERIALS & METHODS A field experiment was conducted at Experimental farm, Rajendra Agricultural University, Pusa, Samastipur, Bihar (India), during 2009-11. The soil of the experimental plot was calcareous, silty clay loam in texture, low in available nitrogen and phosphorus and medium in potassium content. Depth of water applied each time - 6 cm. Total rainfall during crop season – 76.57cm. The experiment was laid out in split plot design with 4 cropping systems in main plot and 3 irrigation regimes for vegetables in sub plot.
TREATMENTS Cropping System: (Main Plots - 6.3 m x 5.0 m) C1- Original lowland rice (Rice – Rice in Kharif & Rabi)
C2- Alternate raised and sunken bed system (Rice-Rice in sunken bed and Brinjal – Cabbage + Radish in raised bed) C3- Alternate raised and sunken bed system (Rice-Rice in sunken bed and Okra – Cauliflower + Radish in raised bed) C4 -Alternate raised and sunken bed system (Rice-Rice in sunken bed and Cowpea–Tomato + Radish in raised bed)
Irrigation Regimes: (for vegetables only) (Sub-Plot - 1.8 m x 5.0 m) I1- 30 mm CPE (Cumulative Pan Evaporation) I2- 40 mm CPE I3- 50 mm CPE
Table -1.Effect of cropping system and irrigation on pooled rice equivalent yield (q/ha). Treatments Irrigation
C1
I1- 30 mm CPE I2- 40 mm CPE
81.56 80.61
99.25 97.69
I3- 50 mm CPE
78.76
Mean
80.31
Source Cropping sequence (C) Irrigation (I) CXI
Cropping system C2 C3
C4
Mean
89.22 86.99
95.26 91.04
90.57 89.08
95.27
83.23
87.38
86.16
97.40
86.48
90.23
S. Em + 1.02 0.60 1.19
CD at 5 % 3.04 1.69 NS
The rice equivalent yield was maximum (97.40 q/ha) under Rice-Rice in sunken bed and Brinjal–Cabbage + Radish in raised bed cropping system, which was significantly superior over Cowpea–Tomato + Radish in raised bed (90.23 q/ha), Okra– Cauliflower + Radish in raised bed (86.48 q/ha) and lowland rice (80.31q/ha). Rice equivalent yield was highest (90.57 q/ha) at 30 mm CPE. However, there was non-significant difference between irrigation regimes of 30 mm CPE and 40 mm CPE, but there was significant difference between irrigation regimes of 40 mm CPE (89.08 q/ha) and 50 mm CPE (86.16 q/ha).
Table – 2 Effect of cropping system and irrigation on pooled net return (Rs./ha). Treatments Irrigation I1- 30 mm CPE
C1 37573
Cropping system C2 C3 54114 44601
C4 48376
Mean 46166
I2- 40 mm CPE
37058
53226
43084
46913
45070
I3- 50 mm CPE 35904 51522 Mean 36845 52954 Source S. Em + Cropping system (C) 1072 Irrigation (I) 544 CXI 1089
40083 42589
44046 46445 CD at 5 % 3128 1540 NS
42889
Net return was significantly higher in Brinjal–Cabbage + Radish in raised bed cropping system (52954 Rs./ha)as compared to Cowpea–Tomato + Radish in raised bed (46445 Rs./ha), Okra–Cauliflower + Radish in raised bed (42589 Rs./ha) and lowland rice (36845 Rs./ha).
Net return were highest (46166 Rs./ha) at 30 mm CPE. However, there was nonsignificant difference between irrigation regimes of 30 mm CPE and 40 mm CPE, but there was significant difference between irrigation regimes of 40 mm CPE (45070 Rs./ha) and 50 mm CPE (42889 Rs./ha).
Table -3. Effect of cropping system and irrigation regime on pooled water productivity (Rs./ha-cm). Irrigation regimes
Cropping system C1
C2
C3
C4
Mean
I1- 30 mm CPE
228.63
423.89
348.92
378.80
345.06
I2- 40 mm CPE
234.01
437.51
353.59
385.36
352.62
I3- 50 mm CPE
235.49
445.54
345.97
380.29
351.82
Mean
232.71
435.65
349.49
381.48
Maximum water productivity (435.65 Rs./ha-cm) was recorded in Brinjal– Cabbage+Radish in raised bed followed by Cowpea–Tomato+Radish in raised bed (381.48 Rs./ha-cm), Okra–Cauliflower + Radish in raised bed (349.49 Rs./hacm) and lowland rice (232.71 Rs./ha-cm). The lowest water productivity of 345.06 Rs./ha-cm was recorded with irrigation regime 30 mm CPE and increased with 40 mm CPE (352.62 Rs./hacm) and was closely followed by 50 mm CPE (351.82 Rs./ha-cm).
Table - 4. Effect of cropping system on pooled Land Use Index (%) and Yield Equivalent Ratio. Irrigation regimes
Cropping system C1
C2
C3
C4
Land use index (%)
76.71
83.56
83.56
86.30
Yield equivalent ratio
-
1.21
1.08
1.12
Land utilization index was the highest (86.30 %) in case of Cowpea– Tomato+Radish in raised bed followed by Okra-Cauliflower+ Radish in raised bed (83.56 %) and Brinjal-Cabbage+ Radish in raised bed (83.56 %) and the lowest (76.71 %) in case of low land rice cropping system. Duration of separate vegetable crops in raised bed was lesser but fetching higher net return and there is scope of introduction of short duration catch crops like leafy vegetables and green gram during summer season. Yield equivalent ratio was the maximum (1.21) in Brinjal-Cabbage+ Radish in raised bed followed by Cowpea-Tomato+ Radish (1.12) and Okra-Cauliflower + Radish (1.08) showing enhanced land use.
Boro rice in Sunken bed
Kharif vegetables on raised bed
Rabi vegetables on raised bed
C0NCLUSION Higher rice equivalent yield, net return, water productivity and land utilization could be obtained with rice in sunken bed and suitable vegetable crops in raised bed by modifying the lowlands in alternate raised and sunken beds. Irrigation at 40 mm CPE to rabi vegetables is most suitable. REFERENCE Singh, R., Kundu, D.K., Mohanty, R.K., Ghosh, S., Kumar, A. and Kanan. K. 2005. Alternate raised and sunken bed system for crop diversification in lowlands. Extension Bulletin. Water Technology centre for Eastern Region (ICAR), Bhubaneswar, India.