In many countries, especially in Africa, growing Jatropha is being seen as a typical smallholders and outgrowers activity. Farmers are promoted to interplant their crops with Jatropha. This is not!! a good development!! Since the farmers grow food crops on better soils, automatically there will be competition. In simple words: where you plant a bean, you can not plant a Jatropha and vice versa!!
On the other hand, planting more than one crop in the same field has many advantages.
- Small farmers are used to intercrop, looking for different food plants to spread the risk of crop failure and anticipating on erratic rainfall. In Tanzania, for example, the combination of Maize and Beans and Pigeon pea is very common.
- If more than one crop is cultivated and harvested with different growing cycles, farmers can use their time more economically.
The amount of time subsistence farmers are spending to grow their own food is greatly underestimated. It was calculated (by Hivos ) that a farmer in Zambia is spending 240 days on a ha of Jatropha, which goes at the cost of time he/she needs to produce food. So they had to be compensated financially for this loss in income, which makes the whole system not very sustainable.
But there are other ways.!!
- In new and unused area’s plant Jatropha always in combination with a food crop.
- Plant Jatropha in hedges, either along boundaries and/or in rows in the field
- Plant combinations of Jatropha and food crops in plantations.
1. Farmers should start to prepare unused area’s to produce Jatropha always in combination with food crops. Planting Jatropha should become a guarantee to increase the food-producing area’s.
Lesson 1. There always is a reason that an area is not used by the farmers. It might be to far from the village, the soil might be poor, there might be a dispute regarding the property of the land etc. These problems should not be underestimated and have to be faced first.
To be successful in intercropping Jatropha with other crops (or other crops with Jatropha), farmers should concentrate on every crop with the same intensity. Forget about the story that Jatropha does not require much water and grows on any soil. The production of Jatropha should be embedded in other crops as within a normal mixed farming system, with all its needs and attention. Even more, growing Jatropha should go hand in hand with the improved agricultural practice for food crops as well, like using better seeds, planting in time and in rows, weeding, using fertilizer or organic manure, etc. etc. This means that farmers should not be compensated with money, but they should be compensated with good agricultural practice training, proper seeds or plants and fertilizers.
Does this mean that Jatropha is (again) competing with food crops? No, with this integrated farming system Jatropha is breaking the way to increase planting area’s and increase the production of food crops, resulting in a 1+1=3 result
It means that by planting Jatropha, the food production area increases as well!!
Since we do not want to compete with existing food-producing area’s, we plant our mixed farming system on unused land and in a special pattern.
A double row of Jatropha planted 2×2 (=4 mtr) and than 6 meter for other crops and/or machinery. This gives us 1000 Jatropha plants(4000m2) per ha and still 6000m2 for another crop to grow in between the Jatropha. (See drawing.)
The space in between the double Jatropha rows is a variable. Actually, it is depending on the type of intercrop and/or the equipment which is going to be used.
Of course, this is just a drawing. No field will be square like this one. On top of that, if the field is on a slope, Jatropha should be planted along the contours.
The effect of Jatropha on poor soils
Initially, poor soils will result in poor harvests. You get nothing for nothing. However, in due time a couple of systems are going to work. Jatropha will gradually develop into a large shrub, providing shade and/or shelter to other crops (depending on planting distance). Furthermore, the roots of Jatropha grow pretty deep and will touch layers where the normal annual crops or weeds do not reach. The nutrients picked up from these layers are reaching the surface via the Jatropha plants. Through pruning and shedding of the leaves, the nutrients will return to the surface, enriching the upper layer where other crops are intended to grow. As the seeds from Jatropha are pressed, the remaining seed cake should be returned to the surface, because it is rich in N, P and K, equal or even richer than chicken manure.
The nutrient value of Jatropha seedcake from different sources compared with chicken manure.
How can Jatropha benefit from intercropping?
Food in between Jatropha.
Presume we are growing beans in between the Jatropha. With a row distance of 6 meters between the Jatropha rows, the beans have ample space to grow. The beans or other crops will grow between the Jatropha, protected from strong winds and excessive radiation. After harvest the root systems will deteriorate, providing the soil with nitrogen. On top of that, the flowering beans or other crops will attract insects, badly needed for the pollination of the Jatropha. Many crops could be intercropped with Jatropha in a way that the intercrop takes advantage of the Jatropha and vice versa. Vanilla is a good example as well but unfortunately, the world does not need much Vanilla nowadays. Farmers should concentrate on the local market. Whenever they can make a good price for melon, they should grow melon in between the Jatropha. The melon crop will make sure that the Jatropha plants get pollinated by insects. Same counts for groundnuts, cowpeas, pigeon peas, sweet potatoes, peppers, corn etc.
Unfortunately, I identified only limited information regarding the influence of Jatropha on the intercrop and vice versa. here
Groundnuts in between Jatropha (Thailand, 2007)
Trees in between Jatropha
In principle, you should not grow Jatropha in a forest, because the forest creates shade and Jatropha needs sun! However, Jatropha plants could take advantage of existing trees (Acacia) or introduced trees (Prosopis*) because those trees attract insects badly needed for pollination of Jatropha flowers. So why not interplanting Jatropha rows with this kind of pollinator trees. The moment they become too big you cut them or prune them and use them for charcoal production or even firewood. You create a sustainable source of firewood and charcoal.
* There are many varieties of Prosopis and Acacia and some become a weed under certain circumstances. Be sure you verify the characteristics of a plant before you introduce it. More info about Prosopis here
These trees also have the potential to become important for the production of honey, provided there is water available for the honey bees
Cattle in between Jatropha
It is known that cattle (goats, sheep, cow) do not eat Jatropha leaves. Apparently these animals are not as stupid as we think they are. This means that you can grow Jatropha in grazing area’s, as suggested by Mike Lu on the other page. They do that in Brazil already. As with food intercropping, ample attention should be given to grow the right type of pasture.
2. Plant Jatropha in hedges along boundaries
. I am not promoting stories like “keeping the goats out” or erosion control on a small scale, because there is no scientific proof for it. Did you ever see a goat pushing itself into a fence? As soon as the head passes, the whole goat passes. But at least they do not eat it. I found a report regarding the supposed positive influence of Jatropha on degraded soils, which you can find here.
Boundaries are everywhere. Housing plots, streets, canals, maize fields, soccer fields; they all have boundaries, requiring maintenance. So most of the time these boundaries become a mixture of poles and trees and wire and weeds or in other words, they become a mess and a burden. Why not planting all these boundaries with Jatropha, providing income in stead of costing money.
Hedges can produce a lot of seed. It is estimated from a project in Mali (by Henning) that a hedge could produce 0.8kg per meter/per year. So if an average farmer has a plot of 0.5 ha (100×50 m), he can plant 300 mtr of Jatropha hedge which will bring him 240 kg of seeds. And so will his neighbour, and his neighbour etc. etc. A km of Jatropha hedge can produce 800 kg of seeds.!
Critics are doubting that you can get enough volume out of a smallholder farming system. However, there are plenty of examples that you can! Think about coffee and tea and cotton and strawberries!. Even a lot of oil palm is grown by smallholders. On top of that, the Mali estimation comes from a very dry area and with an increase in rain you will get an increase in yield of Jatropha seeds. How much? We do not know. Agronomists in Jatropha projects are either very secretive or ignorant about collecting data. This is one of the biggest obstacles for the development of Jatropha. Even the owner of the hedge on this picture did not know how much he picked from the hedge. He only knew it was not enough to run the generator. But he could still recollect the moment he planted the hedge. That was 10 years ago. Why? He did not know either. Probably to make soap which was very popular at the time.
3. Planting Jatropha in plantations outside food production area’s.
There is a lot of negative discussion about planting Jatropha in plantations.
Below are some of the arguments.
One thing is for sure. World wide there is a lot of land available which was used for agriculture 50 years ago. How come?
Improved productivity through better agricultural practices and improved seeds/plants/practices.
The road to the cities. People were leaving remote area’s, hoping they could find a better income in town.
Local or international disputes, causing that millions of people left there living grounds.
When adapting a system where Jatropha per definition has to grow with other crops or other agriculture activities like grazing, there is a guaranty that bio fuel production and food production go hand in hand.
This does not automatically mean that food crops and Jatropha should be mixed in the same field. A good system could be Jatropha/Food crop 50/50 on separate fields. However, in a mixed crop system, the choice of the right combination will be more efficient.
About the Author
Published with kind permission of Ab van Peer.(MASc)