The idea of planting trees
throughout a field crop acreage appears to be catching on in the tropics. At first it was merely a partial restoration
of former practises with sporatic results.
Now science is been applied.
Here we hear about growing a
nitrogen fixer which is then coppiced at the beginning of the growing season.
What we are waking up to is that
we can tackle tropical soils with this, eventually in conjunction with biochar
to lock in nutrients at the surface.
Such trees can also be chosen for deep roots that pull deep nutrients
back up to the surface.
Thus even a widely spaced acacia
planting will deliver deep nutrients and drop an annual crop of leaves for
cattle feed. The planting provides partial
shade during the growing season allowing superior crop production. This all has to be integrated into a
husbandry plan, but it appears that this is actually under way.
It is the early days of
scientific agriculture in Africa , although
those involved will likely take offense for that, but I expect to see African productivity
in agriculture to be spectacular before it is optimized. No one would ever claim it was optimized ever,
but the past decade as information began to flow has seen an eruption of
improvements.
Fertiliser tree systems can double agriculture yield in two thirds of
cases in East Africa
OCTOBER 16, 2011
BBC News - The nitrogen-fixing roots of certain trees provide
valuable nutrients to resource-poor arable land Planting trees that
improve soil quality can help boost crop yields for African farmers, an
assessment shows.
Fertiliser tree systems (FTS) also help boost food security and play a
role in "climate proofing" the region's arable land, the paper adds.
Researchers from the World Agroforestry Centre say poor soil fertility is one of the main obstacles to improving food production in
Some of the studies have shown that in TFS (Tree Fertiliser Systems) across
The Faidherbia tree - pending some further research on its impact on
the water table - may now provide a natural and widespread fertilizer fix.
According to the Agroforestry Centre, farmers in Malawi Malawi Zambia
International Journal of Agricultural Sustainability - Agricultural success from Africa: the case of fertilizer tree systems in southern Africa (Malawi, Tanzania, Mozambique, Zambia and Zimbabwe)
In response to the declining soil fertility in southern Africa and the negative effects that this leads to, such
as food insecurity besides other developmental challenges, fertilizer tree
systems (FTS) were developed as technological innovation to help smallholder
farmers to build soil organic matter and fertility in a sustainable manner. In
this paper, we trace the historical background and highlight the developmental
phases and outcomes of the technology. The synthesis shows that FTS are
inexpensive technologies that significantly raise crop yields, reduce food insecurity
and enhance environmental services and resilience of agro-ecologies. Many of
the achievements recorded with FTS can be traced to some key factors: the
availability of a suite of technological options that are appropriate in a
range of different household and ecological circumstances, partnership between
multiple institutions and disciplines in the development of the technology,
active encouragement of farmer innovations in the adaptation process and
proactive engagement of several consortia of partner institutions to scale up
the technology in farming communities. It is recommended that smallholder
farmers would benefit if rural development planners emphasize the merits of
different fertility replenishment approaches and taking advantage of the synergy
between FTS and mineral fertilizers rather than focusing on `organic vs.
inorganic' debates.
15 October 2011 Last updated at 20:28 ET
Trees 'boost African crop yields and food security'
By Mark KinverEnvironment reporter, BBC News
The nitrogen-fixing roots of certain trees provide valuable nutrients
to resource-poor arable land
Planting trees that improve soil quality can help boost crop yields for
African farmers, an assessment shows.
Fertiliser tree systems (FTS) also help boost food security and play a
role in "climate proofing" the region's arable land, the paper adds.
Researchers from the World Agroforestry Centre say poor soil fertility
is one of the main obstacles to improving food production in Africa .
The results appear in the International
Journal of Agricultural Sustainability.
"In Africa , it is generally
agreed that poor soil management - along with poor water management - is most
greatly affecting yields," explained co-author Frank Place
He said that despite chemical fertilisers having been on the market for
more than half a century, farmers appeared reluctant or unable to buy them.
"Therefore, there have been a lot of attempts to bring in other
types of nutrients from other systems - such as livestock and plants" he
told BBC News.
"We have been working quite a lot on what is broadly referred to
as 'fertiliser tree systems'."
Although it has been known for centuries that certain plants, such as
legumes, "fix" nitrogen in the soil and boost food crop yields, Dr
Place said that the centre's researchers had been looking to develop a more
active management approach such as FTS.
In TFS across Africa as a whole,
yields are doubling or more in two-thirds of cases”
Frank PlaceWAC
"Some farms, for example in Zambia
"But in place such as much of Malawi
While the technique is not new, Dr Place said that some of the
nitrogen-fixing species used by farmers were probably not the most effective.
For example, farmers in East Africa
had been using Cajanus cajan (also known as pigeon pea).
"A lot of the nitrogen was being stored in the trees' seeds; so
there was an effort to use other trees that put a greater volume in the soil,
such asGliricidia sepium (one of its common name is mother of
cocoa)," he said.
"A really nice thing about G. sepium is that we have
been coppicing some of those trees for 20 years and they still continue to grow
back vigorously."
However, he acknowledged that there were a number of challenges that
had to be addressed in order to maximise yields.
For example, some systems suggested planting rows of trees between rows
of crops with mixed results.
"We realised that there were a few management problems with that
sort of system - what tended to happen was that there was too much competition
between the crops and the trees," Dr Place explained.
"We developed a new management system where the trees were cut
very low to the ground at the time you are planting the crop so then there was
no light competition.
"The trees go into a dormant state when you cut them like this, so
the root system is not competing straight away for the nutrients, so the maize
is free to become established.
"The trees only really start to come out of the dormant phase when
the maize is already tall."
Another challenge was to provide enough seeds in order to have
mass-scale planting. He said that balancing the provision of high-quality seeds
with large local engagement was another hurdle that had to be overcome.
But the rewards in improved yields were noticeable, he added.
"Some of the studies have shown that in TFS across Africa as a whole, yields are doubling or more in
two-thirds of cases."
Where the systems were not delivering such good results, Dr Place said
that scientists were looking to refine current practices and modify them to
suit the local conditions.
'Climate proofing'
As well as helping to boost yields, the use of trees in agriculture has
other benefits - such as helping to "climate proof" agriculture land.
One example, Dr Place said, was the use of Faidherbia albida (common
names include winter thorn and apple-ring acacia) in West African arable
landscapes.
"It has a deep penetrating tap root, and it can secure a good
water supply even in dry years," he explained.
"Generally speaking, tree roots do go much deeper than crop roots,
so it is recycling nutrients and water from deeper reaches.
"There are also studies showing that these roots act as conduits
and bring up water to surface root systems (such as those belonging to
crops)."
The editor-in-chief of the International Journal of Agricultural
Sustainability, Professor Jules Pretty from Essex University in , said the
study illustrated that there was a growing movement of agricultural innovations
across Africa that were increasing yields and at the same time improving the
environment.
"Trees and shrubs in agricultural systems seem to break some of
the rules of agriculture - in this case, farmers are using shrubs to create a
diverse rotation pattern rather than year-on-year maize," he told BBC
News.
"The trees fix nitrogen and improve the soil; the leaves can be
fed to livestock; the crops then benefit greatly in subsequent years."
No comments:
Post a Comment