In 2012, using data from the Water Footprint Network, we completed a ground-breaking assessment of the amount of irrigation water used to produce our key agricultural raw materials in all the water-scarce countries we source from. See Water footprint of our agricultural materials section above for further information.
Conserving water through drip irrigation
Adopting more efficient techniques, such as using drip irrigation systems, can help to ensure that farmers use water more efficiently. Drip irrigation systems normally place the water directly into the soil or onto the soil surface. This reduces the risk of run-off and thereby improves water application efficiency. Drip irrigation systems can be classified as traditional drip irrigation system, subsurface drip irrigation and low cost alternative systems.
Drip irrigation for crops such as tomatoes uses tubes to deliver small quantities of water and nutrients straight to the plants roots, leading to less wastage and evaporation than systems such as overhead and furrow irrigation. Drip irrigation involves applying separate droplets of water directly to the plants’ roots via a network of pipelines – dramatically cutting water use by as much as 50%. By creating optimal growing conditions for the plant, it typically also boosts yields by up to 25-35%.
Drip irrigation also helps create improved growing conditions. It can significantly reduce the spread of fungal diseases and because soil does not become soaked through; it also helps to prevent bacterial diseases. In humid conditions the use of fungicide can be reduced by as much as 50%. The use of drip irrigation also enhances irrigation efficiency relative to conventional techniques such as gravity systems, which include flood irrigation of entire fields, and furrow irrigation using shallow channels or ditches to carry water to the crop.
We provide technical support to help farmers convert to drip irrigation. The management of drip irrigation is more complicated than traditional irrigation, so professional training of farmers is often necessary. We work closely together with equipment suppliers to facilitate this. Our focus is on farmers in water-stressed growing areas, where we are confident that drip irrigation can be made profitable. The long-term benefits include significant water savings, increased yield and reduced chemical costs. Thus it contributes to both economic and environmental sustainability.
In Australia, tomatoes have been grown using up to 70% less water and in India, a set of drip irrigation pilots in gherkins produced an average water saving of 40%.
The following are some examples of our work in India, North America and Tanzania.
In India, Marcatus, one of our strategic suppliers of gherkins, has given high priority to driving water conservation with their farmers. They have installed water meters to compare water consumption and yield using drip irrigation with that of flood irrigation in the Tamil Nadu region of India. Marcatus’s aim is to save almost 1 billion litres of water by the end of 2013.
Drip irrigation provides crucial benefits in India, which faces acute water shortages and low agricultural productivity. Any method that can boost yields while cutting water use is particularly welcome to local farmers, and helps us reduce our impact on water resources in regions of scarcity.
We are also working with tomato supplier, Varun Agro in Maharashtra, to implement drip irrigation on a large scale. In 2012 1,155 acres out of 1,208 acres were grown with drip irrigation. We are planning to extend the irrigation system to the rest of the site during 2013.
Unilever Stockton, California has been working on the development of drip irrigation to grow tomatoes in the face of decreasing water availability for irrigation over the last decade.
Studies have shown that growers can reduce water use by up to 20% using drip irrigation versus the traditional practice of furrow irrigation. The block preventing more drip irrigation being used has been the initial cost of the drip system, lack of rotational crops that can use drip irrigation and the technical use of the system. In the last few years Unilever has partnered with several organisations such as the University of California Crop Extension Service, the National Resource Conservation Service, the
California Tomato Research Institute, other processors and many growers to explore and promote the use of drip irrigation. The estimated water savings in the conversion from furrow to drip irrigation is about 6 acre inches or 162,925 gallons per acre. Unilever Stockton’s growers use approximately 9,000 acres to produce 400,000 tons of tomatoes per season.
In the US, we have found that the most striking aspect of conversion to drip irrigation for tomatoes is the significant yield increase of over 25%.
Our tomato growers will convert from furrow to drip over the next ten years and this will involve several different growing areas and different types of water basins varying from a severe water shortage to a plentiful supply of water. All growers are being encouraged to review their water delivery system and educate themselves about the benefits of drip irrigation.
All tomato growing areas are starting to use drip irrigation and all growers are watching their neighbours try drip irrigation. Unilever will build on the growers’ success to promote the drip concept. Most of Unilever Stockton’s tomato growers were using furrow irrigation in 2008 and the plan is to convert 5-10% of our acreage every year to drip irrigation over the next ten years.
We are also working closely with Spanish-speaking irrigators, providing funding and co-funding for training events. In addition, we are bringing together processors and growers to tackle the issue of water scarcity through the Processed Tomato Foundation, which we rejuvenated in November 2009.
In Tanzania we have been conducting research with academic partners and the Tea Research Institute of Tanzania to understand how tea yield and crop quality are influenced by the amount of water supplied to the crop and the irrigation methods used. The latest trials have concentrated on understanding the advantages and disadvantages of drip irrigation, a method that can achieve very high water use efficiency but at high capital cost.
All the water used for irrigation on our tea estates in Tanzania is harvested from within the farms during the rainy season and then stored on the farms in reservoirs and lakes for use during the dry season. Conserving the high proportion of rainforest within the Tanzanian estates (over 50% of the land area) is also vital to ensure that the catchment characteristics and local weather patterns are maintained.
Widening our scope
We have begun to expand our work at farm level to look at the wider impact of agricultural practices and the consequences of competing demands on water catchment areas. This is important because of the wider impact water quality and resources have on our business. Not only do agricultural practices have the potential to cause off-site impacts, they can also be threatened by other activities, such as industry, that affect the supply and quality of water.
This work has led to some positive outcomes, such as Unilever Tea Tanzania's (UTT) planting of 10,000 trees on its own estates and donating 20,000 indigenous trees to communities in its local water catchment area to help conserve water resources. Tea plants require regular rainfall to produce their best leaves and forests are an important factor in ensuring rainfall patterns remain stable and in protecting water catchment areas. Hence UTT's Biodiversity Action Plan places a high priority on maintaining trees.
We use EIGER, a web-based tool, to identify themes related to global climatic change. The tool takes the form of searchable maps and can provide us with information on water vulnerability. This includes information on which areas or regions suffer current water scarcity, or will suffer water scarcity in the future. It also assesses the irrigation water demand for our crops and the different opportunity and risk profiles of two alternative sites.
Developed by our sustainable agriculture team, EIGER has subsequently been used by our manufacturing excellence team to assess water scarcity around our factory sites.
The EIGER database was compiled by a range of R&D organisations and institutes. The information does not date fast and will remain relevant for the next 5-10 years. Read more in Sustainable sourcing.
Preserving water quality
It is equally important to preserve the quality of the water returned back into the ecosystem. We advise our suppliers on the prudent use of pesticides and fertilisers to ensure that water quality is minimally affected. By taking these actions to conserve and preserve water we ensure that our water management strategy does not deprive local communities of their water supplies at the expense of our business activities.
Working with partners
Unilever is a member of the SAI Platform’s Working Group on Water and Agriculture. The Group, which focuses on water practices at farm level, is working on a water footprint for the improvement of water management at farm level. SAI Platform members, including Unilever, started a project in north-west India in mid-2010 to develop a water impact calculator to help farmers decide when to irrigate. The results of this project were presented at the World Water Forum in 2012.