Identifying the Problem - Inefficient Water Use

This blog post acts as a strand to draw upon a few previous blog posts that have touched upon the issue of inefficient water use within agriculture. It is an argument throughout that water use within agriculture in Africa is inefficient but how is it inefficient?

The Environmental

• Water is lost through runoff or evapotranspiration. 
• Wallace (2000) suggested that the relief and gradient of the land determines efficiency of water use in both irrigated and non-irrigated land. Where gradients are steep then runoff is increased and infiltration is reduced. 
• Water supply effects the productivity of field crops more than any other environmental factor (Patterson 1984). This means a shift from increasing area of crop production to increasing efficiency is required. 
• Variability in rainfed yields is large (Kijne 2001). Therefore consistency can increase yields as can irrigation. 

The research into the inefficient use of water resources within the agricultural sector has mainly focused on the environmental characteristics and has demonstrated a need for change in the form of (technological) innovation. 

The Human
It is important to note that inefficient water use cannot be solely blamed on environmental factors with the Millennium Ecosystem Assessment, in 2005), estimating that between 15-35%  of irrigation withdrawals being unsustainable because farmers took more water than was needed. The FAO built on this and suggested that 60% of water diverted for irrigation is wasted (however, this wastage could be down to either human or environmental factors or both). Its suggested that losses are due to improper system design such as inadequate lining of water channels (Dawn) and poor maintenance.

An interesting concept that has not been touched upon in any of the research or articles that I have read is that if food is wasted than surely the water used to grow it is wasted too and therefore that makes it inefficient. It is a curious link which has seen no discussion but I feel its an important point. If we waste less food then we improve efficiency.

The Political
I'm bringing this one in because the discussion of government accountability and preparedness still rages on in the media - BBC News, The Globe and Mail, and the Poultry Site. as South Africa's drought persists. It was originally covered in a previous blog post that essentially drew the conclusion that the responsibility to improve efficiency of water in agriculture is as much the farmer's responsibility (argued by Wallace) as it is the government. It is the government who can store and manage water (along with private companies) which would mean water is available during periods of water stress.

Inefficiencies in water use within agriculture are more complex than environmental characteristics of human wastage and its a complex interaction of these with the political that means waster use within Africa is very inefficient. As Kijne (2001) and Howell (2000) note that efficiency within agriculture has to increase to meet food security needs as the population continues to explode - something which has  been discussed already on this blog.

Solutions to the Inefficient Use of Water in Agricuture

Water is wasted in agriculture. Previous blog posts have already explored this issue and examined the solution of drip irrigation.

In this blog post a range of solutions to inefficiencies in water use within agriculture will be critically examined in the extensive academic literature.

One of the most interesting articles which didn’t just focus on agriculture, came from Abdul-Rahmann et al. (2011) which in summary talked about using water from fisheries to irrigate agricultural land. The use of this water means that water is not wasted and that the water would contain natural fertilizer (from fish excrement). Although this research was not focused on Africa, it is an interesting idea to integrate two different types of agriculture (fish farming and arable farming). However, to be critical not all countries (in Africa) would have developed “modern” fisheries, such as the ones described in the article, that can capture the water and use it for irrigation and a project of this nature (as the article mentions) would be expensive. Landlocked African countries such as Zambia may not be able to afford this or have enough fish farms to make this a viable option.

Small scale fishing in Tanzania (Sand and Land)

Increasing efficiencies in agriculture does not just come in the form of the technology but also in the form of low cost strategies. 

Furthermore, there are other factors that need to be considered as illustrated in Wallace’s (2000) article. The relief and gradient of agricultural land plays an important role in determining the efficiency of water use within both irrigated and non-irrigated farming. Where land is steep surface runoff is high and infiltration into the soil is reduced (so water is not used for plant growth). Runoff of this kind is made up of 25-30% of rainfall in Niger (Rockstrom 1997) and up to 40% in Mali (Stroosnijder and Hoogmeed 1984). It is clear from these studies that reducing the amount of water occurring as surface runoff is important. Extensive work has been done by Lal (1989 and 1991) into such strategies to stop runoff. Adding materials to the land surface such as leaving crop residues or contour hedgerows can reduce runoff by capturing the water and are low cost and accessible to small scale African farmers. Wallace praises the use of mulches to reduce runoff but other studies have suggested that the use of mulches reduce direct soil evaporation (Barros and Hanks 1993). The effects of mulches, and their usefulness, will therefore vary depending on its relative influence on evaporation and infiltration. This would vary with frequency and quantity of rainfall.

Natural and environmentally beneficial, mulches are useful within agriculture (source)

Wallace’s article is extensive in its discussion of inefficiencies in water use within agriculture and provides solutions to problems that I had not considered – I seemed to focus my thoughts on “hard” engineering technologies but clearly low cost solutions such as mulches can be just as effective (and more accessible for small scale farmers).

Inefficiencies in water use within agriculture are huge and the literature and research into them and solutions is even greater and thus future blog posts will continue to explore this issue. 

*please note that Lal 1991 is only available in book form as is Rockstrom 1997. 

Drip Irrigation - the solution?

Irrigation with precision. Drip irrigation in Africa (africaacribusiness)

There is an extensive wealth of news articles and journals describing the benefits and the prosperity that drip irrigation brings to countries within Africa. Many organizations such as iDE believe drip irrigation is key for small rural farmers to enter the wider (international market). In this blog post the benefits of drip irrigation will be examined and an academic article in Scientific American will be critically evaluated. This will help answer the question - is drip irrigation the future for agriculture in Africa?

A Brief History of Drip Irrigation

The concept of drip irrigation was first conceived by Symcha Blass over 70 years ago when he noticed a tree near a leaking faucet exhibited more growth than other trees in the area. 

The Israeli engineer created the first drip irrigation system that has been refined by various manufacturers today. 

Conventional irrigation that involves flooding fields or diverting rivers sees only 30-60% of the water taken up by the plant and is therefore extremely inefficient (see previous blog post about water being a wasted resource). 

Advantages (Burkina Faso as a Case Study)

With individual success stories, the news article hyperlinked above demonstrates a "new" Africa. An Africa of prosperity and increasing wealth (not just financially). It's main point it that takes less water for a better harvest because of the efficient delivery of water. 

An article by Shoji (1977) helps to explain this efficient delivery of water. Drip irrigation can be calculated used equations so that the exact amount of water needed to replenish the amount lost through evapotranspiration is delivered straight to the plants' roots. 

However, a major flaw in this method of drip irrigation is that it seems unlikely that small scale African farmers have the correct education to calculate that. The now dated article in Scientific American also notes that the soil has to be well prepared and fine grained so capillary forces can effectively diffuse the drip of water to the roots of the plant. Therefore farmers have to effectively plough their soil. 

Is drip irrigation the future for agriculture in Africa?

• Water use (for agriculture) is incredibly inefficient and to avoid wasting water a solution has to be found. 
• Drip irrigation DOES provide an effective solution to this. 
• However, how accessible (in terms of usage, cost, maintenance) is it for small scale rural farmers in Africa?

Solar-Powered Irrigation Scheme in Africa

Jocelyn Timperly's recent article in Business Green is really interesting in that is shows how far irrigation systems have come and the adaptation of a certain technology to a certain environment (Africa) and with the aim of being more accessible to small-scale African farmers

However, is £30 for an irrigation pump cheap enough for the average small scale African farmer?