Farmers' participatory approach for improvement of present status of irrigation water utilization in DVC canal command

M. Pramanick, Lecturer (Research) in Agronomy, and S. Mallick, Professor (Research) in Agricultural Chemistry and Soil Science. AICRP on Water Management, Bidhan Chandra Agricultural University, Kalyani, India

SUMMARY

A case study was conducted in the Damodar Valley Irrigation Command in West Bengal, India to understand the existing water utilization pattern below an outlet and to optimise the available water resources through farmers' participatory approach. There is a significant amount of canal water wastage due to untimely release, a lack of regulatory measure at the outlet, free flooding and a lack of field channels. The result is low water use efficiency of the canal irrigation system. Considering the existing situation, an on-farm research project was conducted on a large number of farmers' fields. As a result of these trials, through farmers' participatory activity, it was revealed that out of the total number of farmers in the minor, 36% of potato growers, 25% of rapeseed and mustard growers, and 50% of summer rice growers followed the proven irrigation management methods to achieve higher water use efficiency. In the study area, low water-consuming crops like groundnuts gained popularity over summer rice resulting in a saving of irrigation water particularly during the summer season.

In spite of massive efforts by the Government of India to increase the irrigation potential from 22.6 M ha in 1951 to 79.7 M ha in 1990, the gap between created potential and utilization of water, particularly in major and medium irrigation projects, is increasing alarmingly and productivity still remains low. This is mainly due to inequity of water supply through the canal, mismatch between canal water delivery and crop water requirements and poor management of irrigation water at the field level. In order to enhance and sustain the crop production, it is imperative to pursue effective irrigation management which is acceptable to farmers. Modern water management requires an integrated approach that considers existing agroclimatic and soil conditions, various agricultural inputs including timely and adequate water supply, together with participation of farmers at field level. Hence, the concept of 'on-farm water management' with emphasis on farmer participation at each and every stage of irrigation water management receives considerable attention (Belloncle, 1988).

The Damodar Valley Corporation (DVC) project is the largest multipurpose project in the state of West Bengal. It provides irrigation to 0.39 M ha in the monsoon season and about 0.1 M ha in the winter and summer seasons. However, due to various bottlenecks, the potential utilization of available irrigation water has not so far been achieved. The problems in this command include: the unreliable and untimely canal water supply, non-existence of any regulatory system at the outlet, wild flooding from field to field, lack of field levelling, irrigation channel running at lower contour, improper drainage and, particularly, the ignorance of water management methods among the irrigation water users. The situation requires an 'on-farm research' approach to pinpoint the actual problems at the outlet level and to recommend possible guidelines for efficient water management. In order to develop such a system, an irrigation minor (Sure - Durgapur) in the DVC command with a gross irrigation command of 140 ha has been selected for an operational research programme.

TABLE 1 - Physical properties of soil

Horizon	Depth	Bulk density	Particle density	Sand	Silt	Clay	Bore space	Field capacity	Permanent wilting point	Infiltration rate
	cm	g/c3	g/c3	%	%	%	%	%	%	cm/h
Ap	0-15	1.58	2.65	40.5	51.3	8.2	40.4	30.8	5.39	0.78
A12	15-42	1.58	-	47.5	40.8	11.7	41.5
CI	42-110	1.67	-	50.1	32.6	17.3	37.0
IICS	110-150	1.57	-	38.9	26.7	31.4	40.2

TABLE 2 - Chemical characteristics of soil

Depth	pH 1:2.5	EC MS/cm	CaCO3 %	Organic C %	Total N %	Available Ca + Mg	Available Na	Available K	CEC
							Me./100 gm
0-15	6.8	1.42	0.69	0.45	0.04	7.2	0.85	0.10	14.8
15-42	6.8	0.23	0.69	0.28	0.02	7.0	0.55	0.10	14.8
42-110	6.8	0.33	0.93	0.20	0.02	5.4	0.64	0.15	9.4
110-150	7.7	0.26	1.39	0.10	0.10	10.0	0.96	0.15	15.0

TABLE 3 - Landholding classification of farmers

Area (ha)	Size group	% of total farmers
0.01-1.00	small and marginal	47.5
1.01-2.00	medium	34.1
> 2.01	large	18.4

Soil: The Soil of the irrigation minor belongs to the Typic Fluvaquent family in the Entisol order. The surface soil texture varies from loamy to sandy clay loam. Available moisture capacity in the 1.0 m profile is 0.13 m. The physical and chemical properties of the surface soil of the experimental site are presented in Tables 1 and 2 respectively. The land is generally flat with a 0.32% eastward slope.

Climate: The climate of this region is humid tropical. The summer is hot and humid. The winter is moderate. Average rainfall over the past 20 years is 1 315 mm with 54, 7 and 13 rainy days in the monsoon, winter and summer seasons respectively.

Socio-economic and agricultural situation: Among the population, 60% belong to the farming community, 25% are agricultural labourers and 10% are engaged in other jobs. The distribution of the size of landholding and percentage distribution according to the area under different crops are given in Tables 3 and 4 respectively.

TABLE 4 - Farmer distribution according to the area under different crops

Area of holding (ha)	Percentage of farmers
	Autumn rice	Winter rice	Summer rice	Potato	Mustard
< 1.0	25	56	43	72	55
0.1-0.3	54	36	37	19	45
0.3-0.5	13	7	11	3	-
> 0.5	7	-	8	-	-

Crops: The major crops grown in the command area are autumn rice, winter rice, summer rice, potatoes, rapeseed mustard and sesame. The cropping intensity is 220%. The common crop rotations followed include winter rice - summer rice in lowland areas, winter rice - rapeseed mustard-summer rice in medium land areas, and autumn rice-potatoes/vegetables-sesame/groundnut in medium-upland areas.

Irrigation: Canal irrigation is the main irrigation source in the area through a main lined channel having a discharge capacity of 300 l/s. Seven privately owned shallow tube-wells and one tank are also in use during the winter and summer months. During the monsoon season farmers do not make any field channels but irrigate by wild flooding. In the winter and summer months some field channels are prepared. There is no regulating structure at the outlet resulting in a continuous flow of water. No irrigation beneficiary committee has been formed at the outlet level; however, a farmers' subcommittee has been formed for the smooth functioning of the research programme.

It is clear that the absence of regulating structures at the outlet, untimely release of canal water, wild flooding irrigation and the non-consolidation of farm land reflect the poor performance of the irrigation system. Thus, to match and reconcile water supply with crop water demand and to devise interventions for optimum use of available irrigation potential in this minor an 'on-farm research' programme was conducted for three years on a large number of farmers' fields. The method of implementation was either through demonstration trials or 'on-farm trials' for solving situation specific problems. The goals of this research were optimal water use at field level, increasing cropping intensity by introducing shorter duration crop cultivars, selection of low water demand crops like onions and groundnuts in place of summer rice and avoiding water responsive crop diseases like sheath blight (Rhizoctonia solani) in autumn rice.

FIG 1a: IRRIGATION VOTER SUPPLY AND DEMAND SITUATION OF THE COMMAND AREA (140 ha) DURING RAINY SEASON

FIG 1b: IRRIGATION WATER SUPPLY AND DEMAND SITUATION OF THE COMMAND AREA (96 ha) DURING WINTER SEASON

FIG 1c: IRRIGATION WATER SUPPLY AND DEMAND SITUATION OF THE COMMAND AREA (60 ha) DURING SUMMER SEASON

RESULTS AND DISCUSSION

Weekly evapotranspiration (ET) of different crops grown in the operational research project area were estimated from pan evaporation data and crop factors following the procedure described by Doorenbos and Pruitt (1977). Weekly irrigation water demand for the whole command of the irrigation minor was calculated. Similarly, irrigation water release at the outlet was regularly monitored. From this information, water supply and demand situations of areas on a weekly basis for various crop seasons was obtained. In the rainy season, supply of water, which includes effective rainfall, was always greater than crop water demand, except for a few weeks at the beginning of the season. This is attributed to greater irrigation demand for transplanting autumn and winter rice, which are the predominant crops in this season (Figure 1a). However, in the winter season, the supply of water lagged behind demand and required conjunctive use of available water resources. At the early stage of the season, this deficit was compensated by the moisture reserve of the soil root zone and later in the season farmers practised conjunctive use of groundwater through shallow tubewells installed within the minor (Figure 1b). During the summer season (Figure 1c) the irrigation department restricts the irrigation command by reducing the frequency and amount of canal irrigation, while the farmers have the tendency to extend the cropped area beyond the command. The situation of demand and supply also revealed that canal water supply did not coincide with the major crop establishment periods of that area. Similar situations were also reported by Kaushal et al. (1992) in the Bhakra canal command in Haryana (India), Malano et al. (1993) in the Thup Salao irrigation command in Thailand, and Selviraj and Rajagopal (1994) in the Bhavani Sagar irrigation project in Tamil Nadu (India). Among the cultivated crops, the net irrigation water requirement was greatest for summer rice, followed by winter and autumn rice respectively, while the lowest requirement was for the potato crop (Table 5).

TABLE 5 - Water requirement, effective rainfall and net irrigation requirement for major crops in the irrigation minor

Crop	Total evapotranspiration,-ET (mm)	Percolation loss, P(mm)	Special requirement1, SR (mm)	Total water requirement (ET+P+SR) (mm)	Effective rainfall, ER (mm)	Net irrigation requirement (ET+P+SR- ER) (mm)
Autumn rice	340.70	294.0	150.0	784,7	423.8	361.0
Winter rice	457.46	399.0	150.0	1006.3	374.6	631.7
Summer rice	203.0	336.0	200.0	739.0	104.0	635.0
Potatoes	121.8	-	-	121.8	62.9	58.9
Rapeseed/mustard	104.4	-	-	104.4	6.7	97.7

¹ SR: amount of water needed for puddling.

TABLE 6 - Economic yield, water use and water use efficiency of major crops under study and control area

Crop	Effective rainfall (cm)	Total water use (cm)		Economic yield (t/ha)		Irrigation water use efficiency (kg/ha - cm)
		Study	Control	Study	Control	Study	Control
Autumn rice	42.37	67.33	67.23	4.60	5.14	68.42	76.45
Winrer rice	37.46	69.14	69.14	5.24	4.78	75.78	69.13
Summer rice	10.40	80.89	87.67	5.23	4.78	64.65	54.52
Potatoes	6.29	34.52	25.24	25.95	22.16	751.73	877.97
Rapeseed/mustard	0.67	9.9	6.33	0.95	0.54	103.37	85.30

TABLE 7 - Economic yield, water use efficiency and benefit:cost ratio of some substitute crops in place of summer rice

Crop	Economic yied1 (t/ha)	Water-use efficiency (kg/ha-cm)	Benefit: cost ratio
Onions	8.7 (bulb)	136.63	6.96
Groundnuts	2.80	78.39	3.54
Summer rice	4.95	38.87	2.50

¹ Data reflect average of four farmers for each crop.

To demonstrate proper water management methods to the farmers of the irrigation command, two approximately 10-hectare blocks of crop land, a study and a control, were chosen within the project area. In the control block, farmers were allowed to follow their own irrigation methods. In the study block, recommended irrigation management was followed. The results on irrigation water use efficiency over three years for different crops are shown in Table 6. For autumn and winter rice the recommended irrigation practice could not be adopted due to the free flooding irrigation system. Higher irrigation water use efficiency in the control block of autumn rice was attributed to sheath blight disease in the study area resulting in a decrease in crop yield. In the case of potatoes, rainfall during the crop season resulted in better water use efficiency in the control block. In general, irrigation water use efficiency was greater in the study area compared to the control block.

TABLE 8 - Farmers' perception of recommended water use for different crops grown in the irrigation command

Crop	Average range of irrigation water given (cm)	Percentage of farmers1	Recommended2 quantity of irrigation water (cm)	Economic yield (t/ha)
Potatoes	< 25	23		21.1
	25-30	36	25-30	24.4
	> 10	41		25.5
Rapeseed/mustard	< 10	50		0.49
	10-12	25	10-12	1.27
	> 30	41		0.98
Summer rice	< 120	28		4.4
	120-130	50	120	5.0
	> 130	22		5.5

¹ Based on 40 farmers.
² AICRP on Water Management, BCAU.

To increase the area of summer crops in the project area, low water requirement crops like onion and groundnut were introduced. The aim was to decrease the area of summer rice for better irrigation water use efficiency. From a number of 'on-farm trials', it was revealed that water use efficiency as well as the benefit: cost ratio was higher for both onions and groundnuts compared to summer rice (Table 7). Similar recommendations for onion cultivation in place of summer rice in this agroclimatic region were made by Pramanick et al. (1991).

During the study period, better water management technology generated by Bidhan Chandra Agricultural University, West Bengal, was demonstrated through 'on-farm trials' and 'demonstration trials' and was widely adopted by the farmers. The degree of adoption towards the recommended water use was analysed using various categories of irrigation (Table 8). The analysis reveals that 36% of farmers followed the recommended practice for potatoes, 25% for rapeseed-mustard and 50% for summer rice. Hence, there remains further scope for adopting improved water management through 'on-farm research' towards 100% adoption.

Humid and swampy canopy environment, due to continuous ponding of irrigation water under the medium-lowland situation, favoured multiplication of the soil-borne disease sheath blight of rice, Rhizoctonia solani (Kuhn). Almost all the major varieties of rice were affected during the rainy season resulting in yield losses of varying degree (Table 9). Shallow submergence and higher rates of potash fertilization were found to restrict this disease.

A sizeable amount of irrigation water may thus be saved if a proper matching and reconcilation is made between canal water supply and crop water demand. To achieve this, dynamic planning on cropping pattern and efficient use of available water resources through the active participation of water users at each and every stage of the project is necessary. Bruns (1993) also gave similar views for greater participation of farmers in irrigation development in Thailand, Indonesia and the Philippines.

The following recommendations may be considered for optimization of irrigation water at the minor level:

1. Adoption of individual farm irrigation with the help of field channels.

2. Withhold the supply of irrigation to crop, based on authentic forecasting data of probable rain.

3. Maximum ponded water in rice field should be 50 mm.

4. Selection of low water consuming crops like onions and groundnuts instead of summer rice.

5. Selection of an early maturing rice variety during the summer season for better water use efficiency.

6. Adoption of a rotational system of irrigation based on year-round crop calendar.

TABLE 9 - Effect of fertilizer and water regime on sheath blight disease of winter rice

Major rice variety	Water regime
	Saturated to 3.0 cm (20% area affected)			Above 3.0-5.0 cm (50% area affected)
	Fertilizer (N:K)	Yield (t/ha)	Yield loss1 (%)	Fertilizer (N:K)	Yield (t/ha)	Yield loss1 (%)
Swarna	1 : 1	4.7	18	6 : 1	2.4	52
Masuri
IR 36	4 : 1	3.7	38	5 : 1	2.7	70

¹ Over normal yield in the command.

REFERENCES

Belloncle, G. 1988. Is user participation in hydroagricultural scheme possible? A discussion paper. In: Irrigated Agriculture in Africa. Volume 1 (Keynote addresses). Seminar proceedings 25-29th April, 1988. Harare, Zimbabwe. pp. 81-94.

Bruns, B. 1993. Promoting participation in irrigation: reflections on experience in south - east Asia. World Development (Oxford) 2 (11): 1837 -1849.

Doorenbos, J. and Pruitt, W O. 1977. Guidelines for predicting crop water requirements. FAO Irrigation and Drainage Paper 24. FAO, Rome. 144 p.

Kaushal, R.K., Tyagi, N.K., Sewa Ram, and Sanjoy Bhirud, 1992. Diagnostic analysis of tertiary canal water delivery system and approaches to improved management. Indian Journal of Agricultural Engineering 2 (1): 47-53.

Malano, H.M., Boonlue, C. and McMahon, T.A. 1993. Developing an improved operational strategy for the Thup Salao Irrigation System, Thailand. Irrigation and Drainage Systems 7 (3): 205-220.

Pramanick, M., Mandal, N.N., Pranti Palchoudhury and Chatterjee, B.N. 1991. Onion is more profitable than summer rice in West Bengal. Indian Farming 41 (6): 32-33

Selvoraj, K.V. and Rajagopal, A. 1994. Water management and farmers' participation - A case study in lower Bhavani Project Command, Tamilnadu. In: Proceedings of Fifty-ninth Research and Development Session. Central Board of Irrigation and Power, 1-4 February, 1994. pp. 117-120.

ACKNOWLEDGMENT

The authors are grateful to the Project Director, Directorate of Water Management, Indian Council of Agricultural Research for providing funds and to all staff members of the AICRP on Water Management, ICAR, Memari Centre, BCKV for their help during the investigation.