Recycling plant materials
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CTA. 2008. Recycling plant materials. Rural Radio Resource Pack 08/3. Wageningen, The Netherlands: CTA.
Permanent link to this item: http://hdl.handle.net/10568/57309
Refueling soils using crop residues and manure
Recycling plant materials Cue: As oil prices reach record levels, chemical fertilisers are also becoming harder to afford. But crops need nutrients to grow and if left without fertiliser, soils soon become depleted and unproductive. Using organic matter found on the farm, such as crop residues and animal manure, can be a low-cost alternative to chemical fertilisers. It can also help to build longer-lasting soil fertility and healthier crops with fewer pest and disease problems. At the Fambidzanayi Permaculture Centre in Harare, Zimbabwe, researchers have been investigating how much organic matter, or biomass, crops need to grow well. Edwin Mazhawidza, a research officer, explained more about this to Sylvia Khumalo, and how the system of using organic matter as a fertiliser, known as biomass transfer, works. IN: ?Biomass transfer is a technology ? OUT: ? system can now replicate itself.? DUR?N: 5?21? BACK ANNOUNCEMENT: Edwin Mazhawidza, on how energy stored in plant matter, known as biomass, can be used to increase crop production. The interview comes from a resource pack produced by CTA. Transcript Mazhawidza Biomass transfer is a technology that has been used long back by many farmers. And in the system of biomass, we will be mainly concentrating on the use of things like stover, animal manure in the farming system. These things: straw, crop residue, manure, they contain energy, and also they contain a lot of nutrients which are needed by the plants. So it is a form of renewable energy which is used in the farming system. Khumalo Tell me, are there any geographical limitation or considerations that a farmer has to make before they venture into this type of practice? Mazhawidza There are no geographical restrictions. What is important in this farming system is that a farmer has to do all conservation techniques. Because a farmer may need trees, he may need also grass, and animals must also be integrated in the farming system. So in terms of geographical restrictions, this practice can be applied anywhere, and even in the desert, even in the rainforests or even in the savannah woodlands, provided that a farmer has access to crop residues to straw or even to manure. And if that farmer has access to those things, he or she can retain them. So there are no geographical restrictions when one wants to engage in this biomass transfer as a way of maybe fertilising the soil or even pest and disease management in the farming system. Khumalo Is there any special type of knowledge that a farmer has to have in order to establish this system and also are there any financial implications? Mazhawidza In terms of knowledge, we shall find out that the knowledge which we are using is that knowledge which is local, which is indigenous to the people at a particular place. We then enhance that information with the research which are currently being done now. For example, we can now know the nitrogen, phosphorous, potassium ratios in all those crop residues and in manure. So we are just blending that information with the indigenous knowledge system that has been there. Khumalo I see you have already done some breakdown of the nitrogen, phosphorous and potassium. Of what use is this information to the end user? Mazhawidza When we are talking of this nitrogen, phosphorous, potassium ratio, it benefits the user because we are now talking about plant nutrition. Plants need certain minerals for them to produce food. For example, when we are talking of a crop like maize, maize needs around 200kgs of nitrogen per hectare, 90kg of phosphorous per hectare and also potassium, it needs 70kgs. So the NPK ratio can actually assist a farmer, knowing how much to apply. So that is the reason why we are breaking down these various biomasses, knowing the NPK ratio so that we can recommend the farmer what to use so that they can have a higher yield. Khumalo So how sustainable is this system? Mazhawidza This system is very sustainable. It is economically viable, because a farmer would be using available resources. Like for example cow manure, leaf litter, straw, wood, all those things may be available at the farm. So he may have higher profits because the inputs would be less. So that system is also sustainable in the sense that there is interdependence of elements. For example, animals may depend on plants and plants may also depend on animals so it actually replicates itself, the system. Khumalo Right and Eddie you have also been telling me about your outreach programmes in the community. Can you tell me how that works? Mazhawidza We have got outreach programmes around Zimbabwe, in Mashonaland district, in Matabeleland district, where we are implementing these techniques with farmers. And we are working with around, more than 1,000 farmers. So we are carrying researches with these farmers on biomass transfer. We target specific plants, for example there are plants which have got high nitrogen such as the leucaena species, and we also do research with farmers using their organic manure so that the farmers can have that hands on approach by observing the results. And after observing the results they can know the best technique for them to use. And it appears as if most of them are adopting this biomass transfer because they feed the soil, then the plants can absorb the nutrients from the soil. Unlike chemical fertilisers which can feed the plant directly, but in this biomass they actually work for an average of four years. So although it is labour intensive for the first year, but after the first year the system can now replicate itself. End of track.