Small-scale irrigation – effective solution for sloping land areas

Small-scale irrigation – effective solution for sloping land areas

Small-scale irrigation – effective solution for sloping land areas

10:21 - 15/03/2018

RESEARCH ON THE SCIENTIFIC AND PRACTICAL BASIS TO HARMONISE WATER ALLOCATION WITH WATER TREATMENT FOR IRRIGATION SYSTEMS IN THE RED RIVER DELTA
Community based water quality monitoring: a multi-benefit approach to water governance in the Red river basin, Vietnam
Assessment of climate change impacts on river flow regimes to support decision-making in water resources management in The Red River Delta, Vietnam – A case study of Nhue-Day River Basin
Impact of existing water fee policy in the Red River Basin, Vietnam
Irrigation Modernization in GiaBinh irrigation system, BacNinh province, Vietnam

In recent years, along with the development of the economic sectors, agricultural land areas in delta region are being narrowed. Agricultural production in delta is also threatened by climate change with consequences of sea level rise causing flooding and saltwater intrusion. Therefore, the development of agriculture and forestry in the next decade largely depends on the management and effective and lasting use of hilly land which is very dive

Small-scale irrigation – effective solution for sloping land areas

Potential and challenge of cultivation in sloping land areas

In recent years, along with the development of the economic sectors, agricultural land areas in delta region are being narrowed. Agricultural production in delta is also threatened by climate change with consequences of sea level rise causing flooding and saltwater intrusion. Therefore, the development of agriculture and forestry in the next decade largely depends on the management and effective and lasting use of hilly land which is very diverse, rich in potential. The role of agriculture on slopes, increasingly occupies an important position in the agriculture of Vietnam. However, the development of farming on the slopes encounters two major obstacles, namely: (i) difficulties in water and (ii) the problem of erosion, soil degradation.

Irrigation for sloping land and water scarcity areas

Operation of irrigation schemes in mountainous regions only partially meets water demand for agriculture development. Moreover, the irrigation works are able to be constructed only in areas with favorable topography and available water sources. Sloping land areas with high potential for industrial crops and fruit trees are outside the scope of irrigated areas of hydraulic works. Investment for development of the works in these areas is not feasible or costs too much for O&M as well, which leads to inefficiency.

For sloping lands, storm-water runoff from the traditional farming practices are leading causes of soil erosion, and swept away, which quickly degrades soil and shortens cultivation and land use period. Water harvesting is to collect flows and store water to serve for cultivation; instead of overflow causing erosion. The flow is collected, stored and used in times of crop needs water. On the slopes, water harvesting is an effective measure to protect soil and water.

Case study in Phu Tho province

Figure 1: Scattered rice area, not provided enough water from Te Le reservoir

Source: Thao P. T. P., 2016

Te Le reservoir in Te Le commune, Tam Nong district, Phu Tho province was improved in 2012 with total investment of about 10 billion VND (approximately USD 500,000) from fund of the province, in order to irrigate 4 hectare rice land area. Although it has been upgraded, repaired, due to lower water level during dry season, it fails to provide water for rice cultivation area of 4ha. Thus, the reservoir had not been exploited and used effectively.

At that time, it was 20 hectares of planting forestry area surrounding the reservoir with low economic value trees, such as acacia, eucalyptus. Realizing the potential of water extraction from the reservoir for agriculture on slopes, local authorities have coordinated with an enterprise manufacturing medicinal plants to re-plan agricultural production for the areas around the reservoir and have obtained lot efficiency.

First of all, the 20 hectare area around the reservoir was allocated to the enterprises to restructure from forestry to medicinal plants with higher economic value, shorter harvesting time. Irrigation systems serving medicinal plants were redesigned with criteria to use efficiently water and land resources, avoid waste and reduce soil erosion.

Figure 2: Layout of the irrigated areas using advanced irrigation techniques

Source: Thao P. T. P., 2016

 

Figure 3: Farmers are planting medicinal crops on the field using drip irrigation technique

Source: Thao P. T. P., 2016

 

Water used for irrigation from Te Le reservoir, located about 400m from the irrigated area, is pumped to a water storage pond at the irrigated area with volume of about 400m3. From the water storage pond, a water-saving irrigation system combined with fertilizing is installed to carry water and fertilizers directly to every tree root. Control of fertilizers and irrigation water helps to limit the excessive use of fertilizers causing soil pollution as well as water runoff causing erosion and hardening surface. In addition, because the amount of water for crops is less than that of water needed for rice cultivation, Te Le reservoir is fully able to irrigate 20ha area of upland crops, instead of being not enough water for 4ha rice as before. In addition, the economic value of the upland crops such as pineapple, sesame, medicinal plants is much higher than rice. Economic efficiency of agricultural production has increased due to restructuring of the plant, utilizing sloping land and application of reasonable irrigation techniques, improving income people in the region.

Currently, the local authorities and community are very satisfied with the conversion of the plant as well as the application of small irrigation measures in the region and plans to expand this model to other positions in the commune with similar conditions.

Conclusion

Hilly land in Vietnam at the rate of over three quarters of the natural area is the resource with great potential in agricultural production. The efficient, durable management and use of sloping land will determine the development of agriculture and forestry in the near future. Besides agricultural techniques, applying irrigation measures, water storage measures and irrigation techniques is considered as efficient measures to support sustainable production, soil conservation and erosion control for cultivation on slopes. Small-scale irrigation can be applied easily in the sloping farming areas have irrigation systems but inefficiently operated. It can also be applied for various plants.