Wednesday, June 3, 2015

Deriving Windmill Data from a Bicycle Odometer

Many development projects lack data to support their implementation. This does not mean that the projects are not having a positive impact. It could simply be that the data is harder to collect than the project is to implement. After all, for us to know how much water our windmill is pumping we would have to sit and watch it 24/7. It's just not feasible. Or it wasn't until now.
Our demonstration windmill, which has supplied more than one million liters to the garden, is under its own trial to produce data that can be used for redesign and replication. One of the challenges is to understand the behaviour and performance of the windmill over a long period of time, without constantly having to be present at the garden.
To address this, we have modified a bicycle odometer to record data in real time. On a bicycle, the computer takes input from a magnetic sensor that signals every time the magnet on the spokes goes around one revolution. It is essentially recording RPMs and converting that to distance and speed. We have adapted the computer to record RPMs on the windmill. First, the windmill's RPMs are usually much slower than a bicycle's, so instead of one sensor, we use 6 evenly spaced around the spokes of the windmill. Now the sensor can pick up much slower speeds, but we have to divide all of our measurements by 6.
Next we record the distance, speed, and "trip time", from the computer. Distance corresponds directly to number of rotations. In this case, we use an input tire circumference of 1,667mm in the computer. This yields approximately 100 rotations per kilometer. We can also convert the speed to RPMs. That is, 1 kilometer per hour is approximately 1.67 rotations per minute. The "trip time" simply let's us know how many hours the windmill was moving since the last time we recorded the data.
The piston pump driven by the windmill falls into a category of pumps called "positive displacement pumps", or PD pumps for short. The important thing about PD pumps is that their output is in direct linear proportion to the cycle rate of the pump. (This is in contrast to a centrifugal pump which has a diminishing return on increasing speeds beyond its intended speed). We can convert the RPMs to pump output by multiplying the RPMs by the displacement of the piston. In our case, each stroke of the pump displaces 1.13 liters. So, 1 kilometer per hour is equal to 1.67 RPMs, which is equal to 1.88 liters per minute.
Finally, we can analyze the data from the computer to learn:
1. How much water the windmill pumped
2. Its average speed/output during the times when it was moving
3. The "up time" or proportion of time it was actually moving

Our goal is to maximize the amount of water pumped. When we make modifications to the windmill, we observe changes in the average output and up time. For example, if we decrease the pump displacement, we would expect to see average speed and "up time" increase because there is less resistance. We can now see if these increases are enough to overcome the loss of displacement to pump more water overall.

Using Data to Improve Project Design

The AWP Demonstration Garden is an important component of our project because it is a platform for teaching and research. Already this year we have conducted a tomato trial, resulting in a production of 880 lbs of tomatoes on a 4,500 square foot plot. The results of the tomato trial have been used by two partner organizations in planning their own irrigation activities.
Currently, we are conducting trials of cabbage, onion, tomato (again), potato, and maize. Farmers in the area are observing these trials so that they can learn how to achieve similar results. The results of the trials will guide organizations across Malawi on project design, helping them target realistic goals with their farmers. This is one way we help farmers achieve food security without directly training them ourselves.



Tuesday, May 5, 2015

Irrigation Training

Irrigation allows a farmer to be productive year-round. This means that food production is less weather dependent, and more in the farmers own hands. Farmers who practice only rainy season planting must harvest their entire annual food requirement at one time. If the harvest is too little, better luck next year. But farmers who adopt irrigation can take their rainy season harvest as a starting point, adding grain, protein, and vegetables strategically to make it through the year with plenty of food on the table.

There are other techniques farmers use to stretch the rainy season harvest. They can sell products when the market price is higher, thereby having to sell less. They can practice better farming methods to increase overall yields. They can ration the harvest equally throughout the year to avoid total famine. Improving storage, processing, and cooking methods can boost efficiency. But irrigation has a multiplying effect on all of these strategies. 

More than 50 farmers have already been trained this year. Another class of over 100 are entering the training phase. The expected increase in yield should total more than 30 metric tonnes. That's enough to feed you for the next 50 thousand days, or more importantly, 200 families for an additional 2 months per year - long enough to break the cycle of hunger.

Monday, March 23, 2015

Tomato/Maize Trials

Our demonstration garden at Mziza is primarily platform for teaching about irrigation, but it also serves as a place for trials and experiments. Over the past four months, we have been conducting trials on maize and tomatoes.
We planted 2,000 individual tomato plants on area of 4,500 square feet, or about 1/10 of an acre. We spent $50 excluding labour to grow the plot for 4 months. At harvest, we collected 400 kilograms (880 lbs.) of tomatoes and sold them for about $190. This success can easily be replicated and exceeded by our farmers, if they manage their crops properly. The income from such a small plot would be equivalent to more than 3 months living expenses.
For our maize, we wanted to attempt early planting with irrigation, that would be met with rains mid-growth. This technique is effective when rain patterns are unpredictable. After the first 6 weeks of irrigation, the seasonal rains took over watering duties. This relieved the farmers of the workload of irrigating the maize at exactly the time they needed to be planting other crops at the start of the rains. In late February, the maize was ready for eating as corn on the cob. By March, it was ready for making nsima, the local staple dish. 
Farmers can adopt this technique of early planting and preempt the hunger that strikes most communities in February-April. Many farmers are already using this method, and that will be a good thing this year, when rains have stopped before the rain-planted maize has matured. Early planted maize will provide a small, but needed bump to the annual harvest and give farmers more time to look for other solutions to the below average yields.

Thursday, March 12, 2015

Composting Training

As training continues, farmers will get out of the classroom and into their fields. The first test of the trainees' muscle is to make a compost heap of 8 cubic meters, a 2 by 2 meter cube of grass, leaves, manure, and crop residues. The compost heap will decompose into about 1 ton of nutrient rich compost that can be used to grow 1/4 acre of corn or vegetables. It is equivalent to about $50 worth of fertilizer.



Composting not only provides nutrients but reduces the risk involved when investing heavily in chemical fertilizer. If the crop fails due to weather or the farmer falls ill during the season, the fertilizer is wasted. Compost does not wash out of the soil as quickly and only costs the farmers time to gather the composting materials.



Monday, February 9, 2015

Establishing Farming Clubs

Mphimbi Club invited the local chiefs to
the training (seated on the right)
Club Formation

In January, AWP worked with three new communities to establish farming clubs. The clubs form the basis of our partnership with the farmers, but also give the farmers themselves a platform to create positive change in their community. We discourage the idea (which always crops up) that such clubs are "AWP Clubs". On the contrary, these clubs are independent, persistent, and autonomous. They will work with other organizations, agri-businesses, and government extension officers. They invite AWP to their meetings, rather than AWP calling them to a training. They manage themselves, which is important for the sustainability of the club.

The clubs begin by discussing the many reasons people do farming. To have enough food for their families, to earn income, to preserve the land for their children, and to provide for the sick, elderly, and bereaved, are all common answers. From this, the club will decide on an overall goal, a mission statement, for their charter.
Mphombe Club members gather at a local church
Self-evaluation

The club then must determine how they will know if they are being successful as a group. They will need to identify the observable outcomes of their success (e.g. the quantity of food produced, income earned), and track them over time. This is the capacity for self-evaluation that will ensure the club don't look to AWP or any other organization to know whether they are being successful. 

By self-evaluating, the club will be in a better position to maintain and grow its membership. Everyone will know exactly what benefits the club is offering them. By using multiple measures of success (production, income, nutrition, persistent availability of food), the club will have as many opportunities of achieving something that will give them hope and motivate them to improve. If you don't know what you're aiming for, you don't know how much you have achieved.
The Mphombe Club chairman gives a final word of encouragement

Friday, January 16, 2015

Small Plates

The lean months have started. Kids scrounge maize kernels that have dropped from grain silos and storage sacks. Roasted and served on a tin lid, the snack holds them over lunch.
By providing input loans at Mziza, AWP ensures that farmers and their families avoid this situation. Club members continue to rely on the harvest from 7 months ago. The effects of food security on their families go far beyond what we can observe.