Dedicato a quelli che "La Monsanto sfamerà il mondo".

[San Siro]

Scientists find that evergreen agriculture boosts crop yields

November 2, 2010

A unique acacia known as a "fertilizer tree" has typically led to a doubling or tripling of maize yields in smallholder agriculture in Zambia and Malawi, according to evidence presented at a conference in the Hague today. The findings were central to the arguments of agroforestry experts at the conference, who urged decision makers to spread this technology more widely throughout the African nations most vulnerable to climate change and food shortages, and to think differently about more practical ways to solve the problems that are most pressing to smallholder farmers.

Speaking today at The Hague Conference on Agriculture, Food Security and Climate Change, Dr. Dennis Garrity, Director General of the World Agroforestry Centre, said that evergreen agriculture—or the integration of fertilizer trees into crop and livestock-holding farms—is rapidly emerging as an affordable and accessible solution to improving production on Africa's farms.
"Doubling food production by mid-century, particularly in Africa, will require nonconventional approaches, particularly since so many of the continent's soils are depleted, and farmers are faced with a changing climate," Garrity said. "We need to reinvent agriculture in a sustainable and affordable way, so that it can reduce its emissions of greenhouse gases and be adapted to climate change."
Garrity spoke to leading agriculture and climate scientists, policymakers, development experts, and private sector representatives from around the world gathered at The Hague to develop a concrete action plan for linking agriculture-related investments, policies, and measures to transition agriculture to lower carbon-emitting, climate-resilient growth.
In a recent article in Food Security, Garrity and co-authors highlighted how evergreen agriculture has already provided benefits to several million farmers in Zambia, Malawi, Niger and Burkina Faso. Fertilizer trees draw nitrogen from the air and transfer it to the soil through their roots and leaf litter, replenishing exhausted soils with rich sources of organic nutrients. The trees bolster nutrient supply, increase food crop yields, and enhance the production of fodder, fuel and timber. These systems also provide additional income to farmers from tree products, while at the same time storing much greater amounts of carbon than other agricultural systems.
For example, farmers in Malawi have increased their maize yields by up to 280 percent when the crop is grown under a canopy of one particular fertilizing tree, Faidherbia albida. Unlike most other trees, Faidherbia sheds its leaves during the early rainy season and remains dormant during the crop-growing period. This makes it highly compatible with food crops because it does not compete with them for water, nutrients, or light—only the bare branches of the tree's canopy spread overhead while crops of maize, sorghum, or millets grow to maturity below. The leaves and pods also provide a crucial source of fodder in the dry season for livestock when nearly all other plants have dried up. The trees may continue to provide these cost-free benefits for up to 70 to 100 years.
In Niger, there are now more than 4.8 million hectares of millet and sorghum being grown in agroforests that have up to 160 Faidherbia trees on each hectare.
The Intergovernmental Panel on Climate Change (IPCC) has already noted that transforming degraded agricultural lands into agroforestry has far greater potential to store carbon than any other managed land use change.
Researchers suggest that integrating agroforestry into farming systems on a massive scale would create a vital carbon bank. The IPCC estimates that a billion hectares of developing country farmland is suitable for conversion to carbon agroforestry projects.
A broad alliance is now emerging of governments, research institutions, and international and local development partners committed to expanding evergreen agriculture and agroforestry. The International Fund for Agricultural Development, the Alliance for a Green Revolution in Africa, the European Union, the Consultative Group on International Agricultural Research, and the UN Environment Programme are among those interested in developing partnerships to move the evergreen agriculture agenda forward.
"We are already working with 18 countries across the African continent to develop national plans for the accelerated implementation of evergreen agriculture," Garrity explained.
The next step is to further refine and adapt the technologies to a wider range of smallholder farming systems in diverse agricultural environments, so that millions more farmers can benefit now and for generations to come from such sustainable solutions to their food production challenges.
"Evergreen agriculture allows us to glimpse a future of more environmentally-sound farming where much of our annual food crop production occurs under a full canopy of trees," said Garrity.

[San Siro]

Hope is evergreen

di DENNIS GARRITY

Director General, World Agroforestry Centre

Africa needs to increase its food production dramatically, and to do so in a way that is sustainable, affordable and does not further threaten biodiversity. Already around 30 per cent of its people — some 218 million — struggle with hunger daily and its population is predicted to grow from about 796 million in 2005 to 1.8 billion by 2050. Yet food production per head has been declining and yields of cereals have remained stagnant since the 1960s.
At the same time the size of landholdings has consistently shrunk: four out of every five of the continent’s farms are now of less than 2 hectares in size. Farmers are trying to increase yields on smaller farms with poor soils, amid increasing climate variability and with long-term climate changes ahead. Often, their only hope of producing more food is to expand cultivation by felling forests, posing a major challenge to biodiversity conservation.
Science-based solutions that build on the best of local knowledge and practices — and are truly accessible and affordable — are the only way of ensuring agricultural growth that combats extreme poverty while preventing further deforestation. And hundreds of thousands of smallholder farmers in Zambia, Malawi, Niger and Burkino Faso have indeed shifted to farming systems that are restoring exhausted soils and dramatically increasing both crop yields and incomes. They are applying the principles of evergreen agriculture, which is emerging as a practice of enormous potential not just for increasing crop yields but also for introducing more trees into farms and preventing forest loss. It can be broadly defined as conservation farming that integrates trees with annual food crops and cover crops. Conservation farming is already practised on 100 million hectares of land around the globe. It involves three basic principles: disturbing the soil as little as possible (through minimum or zero tillage); keeping the soil covered with organic material like crop residues; and rotating and diversifying crops, particularly using leguminous species that replenish soil nutrients.
In evergreen agriculture, incorporating trees into farming systems — a practice known as agroforestry — is added to these principles. The trees usually offer many benefits to the farmer and the environment, including providing green fertilizer to build healthier soils and enhance crop production, and yielding fruit, medicines, livestock fodder, timber and fuelwood. They also provide shelter, control erosion, increase biodiversity and offer greater resilience to climate change, while storing carbon.
Fertilizer trees — which draw nitrogen from the air and transfer it to the soil through their roots and leaf litter — have been shown to be able to double average maize yields or more. This equates to an extra three to four months’ supply of maize for a family of six, assuming the average African consumes 1.5 kg a day.
One special fertilizer tree — Faidherbia albida, an indigenous African acacia already a natural component of farming systems across much of the continent — could be the cornerstone of future evergreen agriculture. It exhibits “reverse leaf phenology”, meaning that it sheds its nitrogen-rich leaves during the early rainy season and remains dormant throughout the crop-growing period: the leaves grow again when the dry season begins. This makes it highly compatible with food crops, because it does not compete with them for light, nutrients or water during the growing season: only its bare branches spread overhead while the food crops grow to maturity.
In Malawi, maize yields have increased by up to 280 per cent when grown under the canopy of Faidherbia trees. In Zambia and Malawi more than 100,000 farmers have extended their conservation farming practices to include cultivating food crops within agroforests of Faidherbia trees. Extensive observations indicated that maize grown near the trees is dramatically more productive, and that the soil gets healthier. And in Niger, there are now about 4.8 million hectares of Faidherbia- dominated agroforests enhancing millet and sorghum production.
Evergreen agriculture offers an affordable and accessible science- based way of better caring for the land and of increasing smallholder food production. It allows us to glimpse a future of more environmentally benign farming, with much of our annual food crops being produced within a forest of full-canopy trees.
Most clearing of forests for agriculture is done by subsistence farmers striving to increase their production and incomes, and to escape poverty. As rural population densities continue to rise, natural forests — and the services they provide — are increasingly threatened. A broad adoption of evergreen agriculture offers smallholder farmers the opportunity of improving their land’s productivity, thus alleviating the need for further agricultural expansion and potentially leaving more natural forest intact.
Increasing agroforestry also offers the potential to produce forest goods and services on farms, and so further protect biodiversity. And if carbon markets were to become accessible to smallholder farmers, this would result in an ever greater number of trees in agricultural landscapes.
Such experiences with evergreen agriculture and Faidherbia offer the basis for a proposed expansion across Africa. A broad alliance is emerging of governments, international donors, research institutions and international and local development partners committed to expanding this innovative approach to farming throughout the continent.

This article has been compiled with assistance from the World Agroforestry Centre’s regional coordinators: Festus Akinnifesi (Southern Africa) Jeremias Mowo (East Africa) and Antoine Kalinganire (Sahel).

[ramirez]

For example, farmers in Malawi have increased their maize yields by up to 280 percent when the grown under a canopy crop is of one particular fertilizing tree, Faidherbia albida. Unlike most other trees, Faidherbia sheds its leaves during the early rainy season and remains dormant during the crop-growing period. This makes it highly compatible with food crops because it does not compete with them for water, nutrients, or light—only the bare branches of the tree's canopy spread overhead while crops of maize, sorghum, or millets grow to maturity below. The leaves and pods also provide a crucial source of fodder in the dry season for livestock when nearly all other plants have dried up. The trees may continue to provide these cost-free benefits for up to 70 to 100 years
.
ho capito bene, ci sono alberi che aiutano i raccolti.
Devo presumere che il raccolto avvenga a mano...faccio fatica
ad immaginare macchine agricole che operino efficacemente
con alberi in mezzo alle...ruote.

[San Siro]

Originalmente inviato da ramirez

For example, farmers in Malawi have increased their maize yields by up to 280 percent when the grown under a canopy crop is of one particular fertilizing tree, Faidherbia albida. Unlike most other trees, Faidherbia sheds its leaves during the early rainy season and remains dormant during the crop-growing period. This makes it highly compatible with food crops because it does not compete with them for water, nutrients, or light—only the bare branches of the tree's canopy spread overhead while crops of maize, sorghum, or millets grow to maturity below. The leaves and pods also provide a crucial source of fodder in the dry season for livestock when nearly all other plants have dried up. The trees may continue to provide these cost-free benefits for up to 70 to 100 years
.
ho capito bene, ci sono alberi che aiutano i raccolti.
Devo presumere che il raccolto avvenga a mano...faccio fatica
ad immaginare macchine agricole che operino efficacemente
con alberi in mezzo alle...ruote.

Proprio così.

Non puoi avere un'agricoltura che protegga indefinitamente la fertilità dei suoi e nel contempo lo 0,5% degli individui impiegati nel settore agricolo.

Puoi meccanizzare anche nel caso qui descritto, ma non su scale molto elevate.

Ecco un esempio pratico di decrescita, per rifarsi a un thread aperto in questi giorni e molto attivo.

[ramirez]

ti segnalo questo dibattito sull'Economist.
Ecco le posizioni che si confrontano
.
The number of people on Earth is expected to increase from the current 6.7 billion to 9 billion by 2050. How will we feed them? Genetically engineered crops will play an important role.
.
la mozione contraria
.
Biotechnology is not a system of farming. It reflects no specific philosophy nor is it guided by a set of principles or performance criteria. It is a bag of tools than can be used for good or evil, and lots in between.

[San Siro]

Originalmente inviato da ramirez

ti segnalo questo dibattito sull'Economist.
Ecco le posizioni che si confrontano
.
The number of people on Earth is expected to increase from the current 6.7 billion to 9 billion by 2050. How will we feed them? Genetically engineered crops will play an important role.
.
la mozione contraria
.
Biotechnology is not a system of farming. It reflects no specific philosophy nor is it guided by a set of principles or performance criteria. It is a bag of tools than can be used for good or evil, and lots in between.

Le prima definizione semplicemente non è vera. Nessun sostenitore degli OGM accetta metodi agricoli alternativi rispetto alla moderna agricoltura industriale. Quindi il concetto che gli OGM possano svolgere un ruolo importante nella produzione di alimenti è una semplice tautologia, è un'affermazione che è vera solo perché si sono scelte determinate premesse.

La seconda è apparentemente corretta, ma in realtà non lo è. E' vero che gli OGM sono uno strumento utilizzabile all'interno di ogni sistema agricolo, ma per il tipo di metodologia che sottendono è funzionale a certi tipi di agricoltura e non ad altri. Non è neutrale neanche dal punto di vista epistemologico: la funzione del gene implicita nella filosofia OGM, che possiamo chiamare "riduzionismo genetico" può non rispecchiare il funzionamento reale dei geni.

E' ovvio che essendo L'Economist favorevole agli OGM, nel contrapporre posizioni opposte cerca di fare in modo che quella contraria non sia poi così contraria, anzi, di fatto appaia più che possibilista.

Puoi segnalarmi il link dove compare questa discussione?

[ramirez]

Originalmente inviato da San Siro

Le prima definizione semplicemente non è vera. Nessun sostenitore degli OGM accetta metodi agricoli alternativi rispetto alla moderna agricoltura industriale. Quindi il concetto che gli OGM possano svolgere un ruolo importante nella produzione di alimenti è una semplice tautologia, è un'affermazione che è vera solo perché si sono scelte determinate premesse.

La seconda è apparentemente corretta, ma in realtà non lo è. E' vero che gli OGM sono uno strumento utilizzabile all'interno di ogni sistema agricolo, ma per il tipo di metodologia che sottendono è funzionale a certi tipi di agricoltura e non ad altri. Non è neutrale neanche dal punto di vista epistemologico: la funzione del gene implicita nella filosofia OGM, che possiamo chiamare "riduzionismo genetico" può non rispecchiare il funzionamento reale dei geni.

E' ovvio che essendo L'Economist favorevole agli OGM, nel contrapporre posizioni opposte cerca di fare in modo che quella contraria non sia poi così contraria, anzi, di fatto appaia più che possibilista.

Puoi segnalarmi il link dove compare questa discussione?

entra nella homepage de l'Economist
sulla dx noterai un riquadro Economist debate..entra è tutto free

[Rumenta]

l'ennesimo esempio di quanto sia devastante far entrare società basate sul profitto negli organi di controllo...

in ogni settore

[San Siro]

Originalmente inviato da ramirez

entra nella homepage de l'Economist
sulla dx noterai un riquadro Economist debate..entra è tutto free

Me lo leggerò con interesse, grazie.

Ma secondo te, perché questo dibattito viene sponsorizzato da un'azienda attiva nelle biotecnologie?

[Rumenta]

Originalmente inviato da San Siro

...viene sponsorizzato da un'azienda attiva nelle biotecnologie?

è l'errore concettuale di cui l'occidente deve liberarsi

VIA LE AZIENDE DAGLI ORGANI DI VALUTAZIONE