Showing posts with label Soil Management. Show all posts
Biochar: a Slow-Burn Success
Posted by Unknown in Biochar, Budget and Funding, FAO and UN, Gardening, Organic, Soil Management on Tuesday, 14 May 2013
Biochar could help you get more from your plants and save the planet at the same time. What's the secret?
By Lia Leendertz
Telegraph
 |
| Growth area: Daylesford Organic gardener Jez Taylor extols the virtues of biochar, which has improved his germination rates his germination rates Photo: Christopher Jones |
Farmers in
Belize are excited about it, as are carbon capture scientists, the
United Nations Development Programme (UNDP), and multinationals such as
Kraft and Nestlé. It may provide a carbon sink, it may save degraded
soils, it may alleviate rural poverty.
"It" is
biochar. For Jez Taylor, the head gardener at Daylesford Organic, the
attraction is more simple: "The environmental benefits and its ability
to capture carbon are delightful, of course. But I just get fantastic
propagation results when I'm using it. That's what I'm interested in."
Biochar is "the
oldest new thing you've never heard of", to quote a phrase coined by
Wae Nelson, a US biochar expert, and its applications are wide ranging.
It is essentially charcoal, but burnt at a lower temperature and with a
more restricted flow of oxygen. Its proponents believe it was the force
behind ancient cities in the depths of the Amazon, where poor, acidic,
tropical soils would not otherwise have been able to sustain large
populations. In such sites up to 2m (6ft 6in) of terra preta (Portuguese
for "black earth") can be found: rich, dark and fertile pockets that
occur naturally among the yellow surrounding earth.
Jez Taylor is
one of a number of head gardeners who are pioneering the use of biochar
in Britain. He manages 20 acres and six polytunnels of crops that supply
Daylesford's own upmarket farm shops in the Cotswolds and London, and
his main interest is in propagating the many plants that will fill those
fields. Each starts off in a tiny plug of compost, desperately
vulnerable to drying out.
"I don't claim
to be an expert propagator, and often we have apprentices watering who
may be even less expert," he explains. "The compost needs to be
bombproof or young plants will be lost, particularly those in tiny
modules, such as spring onions."
Conservationists call on Government to back ban on 'bee-killing' pesticides 13 Mar 2013
Jez tried a mix
of coir and biochar and found that the water-holding action of the
biochar improved his results dramatically. "I now know I can water on a
Friday and come back in on Monday to find that everything is OK. I can
be certain that seeds are still moist at the crucial moment when the
root emerges from the seed, and last year this improved germination
rates from around 80 per cent to closer to 95 or 100 per cent."
Jez also uses a biochar-based compost for larger vegetables that go into the shops for sale as plants.
"It is great in
the potting mix and I'm convinced it gives it more guts. Plants seem to
be supported for longer and there is less yellowing of leaves. When we
feed, the feed isn't given in one go but locked away by the biochar and
released slowly to the plant, and it really shows."
Dr Saran Sohi,
of the UK Biochar Research Centre, started his career researching soils
and soil additives. He says the effect biochar has on soil is different
from that of any other additive.
"Biochar brings
a physical and permanent change to the soil. Every other additive
decomposes but biochar remains, and its effects increase over time."
Biochar works
in several ways. Though it is not filled with nutrients itself, it is
able to attract and hold on to nutrients, so preventing them from
leaching away, and holding them just where plants can reach them. Its
porous nature provides refuges for mycorrhizal fungi, which in effect
enlarge the plant's root system while also increasing its resistance to
diseases. It makes soil far more attractive and stable for beneficial
microbial activity. Essentially it does everything organic matter does
to the soil, but better, and permanently.
All this goes
some way to explaining the impressive results seen in Belize. Craig
Sams, founder of Green & Black's chocolate, has a strong interest in
biochar, having founded a company, Carbon Gold, that sells biochar
mixes and kilns.
"I've been in organic food most of my life, so I've seen the difference that good soil management can make," he says.
He wanted to
bring the two parts of his work together and see what impact biochar
could have on cacao growers' crops. Two Belize farmers were taken to
Cornell University and "pumped on biochar", as Sams puts it. On their
return they were given kilns and asked to put what they had learnt into
practice. The results surprised everyone. Cacao plants planted into soil
rich in biochar started producing fruits when about three-and-a-half
years old; they usually take seven years to reach this maturity.
This caught the
eye of the UNDP, which has now provided $50,000 (£32,900) for more
kilns, and there are several non government organisations working to
create biochar gardens throughout Africa and the Third World. Large food
companies have also started getting in on the act: a sure sign that the
enthusiasts are onto something. Unlike charcoal – which is made from
hardwood at high temperatures – biochar is made at low temperatures and
from any waste, including animal dung, twiggy waste, softwoods and rice
husks, making it a realistic proposition for farmers in developing
countries.
"When diseases
hit plants grown in biochar-rich soils they have to fight their way
through a shield of beneficial fungi and bacteria, and we think this is
why the Belize plants produced so much earlier than usual. They could
grow unhindered," says Sams. In Britain he is working with Bartlett Tree
Experts on a trial with ash trees infected with ash dieback, to see if
biochar might give them a similar increase in armoury.
Elsewhere, Ed
Ikin at National Trust property Nymans is the first head gardener to
install a biochar kiln to deal with his garden's waste and improve its
soils, and Great Dixter head gardener Fergus Garrett uses biochar in his
compost mixes.
"It's an excellent peat substitute," says Garrett. "Better than green waste. I would use it as part of a John Innes mix."
While biochar's
effect on soils and plants is exciting, there are also great
environmental benefits to its manufacture and use, and these stem from
its capacity to lock up carbon. Soil is naturally a carbon sink – it
locks away carbon and prevents it from entering the atmosphere – but a
chunk of our troublesome greenhouse gases arises from ploughing soil and
releasing this carbon. Although normal composting and mulching takes
carbon in the form of organic matter and puts it into the soil, this
quickly breaks down as matter rots, and the carbon is released again.
Every time we dig or disturb the soil we speed up this process. Peat
mining is an extreme example of this: when we disturb peat bogs we
release carbon that was locked away thousands of years ago. But at least
50 per cent of the carbon in any piece of waste turned into biochar
becomes permanently stable.
Gardeners digging biochar into their soils are taking a small step in undoing the environmental damage caused by peat users.
While Dr Saran
is particularly enthused about the use of biochar in tropical climates,
he thinks it could have applications in British gardens.
"In the average
back garden you can make a big impact," he says. "A little can have a
big effect on the soil. The way biochar interacts with water, nutrients,
microbes and fungi will improve growing conditions and make soils more
stable and fertile."
Soil pH and Plant Nutrients
Posted by Unknown in pH, Soil Management, Soil Nutrients on Monday, 13 May 2013
Farmers
frequently ask, "What effect does pH have on availability of nutrients
in the soil?" There is no simple answer to this question, since the
effects of pH are complex and vary with different nutrients. However,
some broad generalizations are useful to keep in mind when making
nutrient management decisions.
Soil pH
The first order
of business is a quick review of pH and the associated terminology.
Soil pH or soil reaction is an indication of the acidity or alkalinity
of soil and is measured in pH units. The pH scale goes from 0 to 14 with
pH 7 as the neutral point. As the amount of hydrogen ions in the soil
increases, the soil pH decreases, thus becoming more acidic. From pH 7
to 0, the soil is increasingly more acidic, and from pH 7 to 14, the
soil is increasingly more alkaline or basic.
Using a strict
chemical definition, pH is the negative log of hydrogen (H+ ) activity
in an aqueous solution. The point to remember from the chemical
definition is that pH values are reported on a negative log scale. So, a
1 unit change in the pH value signifies a 10-fold change in the actual
activity of H+, and the activity increases as the pH value decreases.
To put this
into perspective, a soil pH of 6 has 10 times more hydrogen ions than a
soil with a pH of 7, and a soil with a pH of 5 has 100 times more
hydrogen ions than a soil with a pH of 7. Activity increases as the pH
value decreases.
Agronomists
generally use soil pH as measured in a 2:1 water-to-soil mixture as an
index of a soil's acidity or alkalinity. In a soil test report, pH is
often reported with descriptive modifier as shown in Table 1.
|
Table 1. Soil pH and
Interpretation
|
||||||
|
5.0
|
5.5
|
6.0
|
6.5
|
7.0
|
7.5
|
8.0
|
|
Strongly
Acid |
Medium
Acid |
Slightly
Acid |
Neutral
|
Neutral
|
Mildly
Alkaline |
Moderately
Alkaline |
 |
Best Range for Most Crops
|
|
||||
Nitrogen
One of the key
soil nutrients is nitrogen (N). Plants can take up N in the ammonium
(NH4+) or nitrate (N03-) form. At pH's near neutral (pH 7), the
microbial conversion of NH4+ to nitrate (nitrification) is rapid, and
crops generally take up nitrate. In acid soils (pH < 6),
nitrification is slow, and plants with the ability to take up NH4+ may
have an advantage.
Soil pH also
plays an important role in volatization losses. Ammonium in the soil
solution exists in equilibrium with ammonia gas (NH3). The equilibrium
is strongly pH dependent. The difference between NH3 and NH4+ is a H+.
For example, if NH4+ were applied to a soil at pH 7, the equilibrium
condition would be 99% NH4+ and 1% NH3. At pH 8, approximately 10% would
exist as NH3.
This means that
a fertilizer like urea (46-0-0) is generally subject to higher losses
at higher pH. But it does not mean that losses at pH 7 will be 1% or
less. The equilibrium is dynamic. As soon as a molecule of NH3 escapes
the soil, a molecule of NH4+ converts to NH3 to maintain the
equilibrium.
There are other
factors such as soil moisture, temperature, texture and cation exchange
capacity that can affect volatilization. So pH is not the whole story.
The important
point to remember is that under conditions of low soil moisture or poor
incorporation, volatilization loss can be considerable even at pH values
as low as 5.5.
Soil pH is also
an important factor in the N nutrition of legumes. The survival and
activity of Rhizobium, the bacteria responsible for N fixation in
association with legumes, declines as soil acidity increases. This is
the particular concern when attempting to grow alfalfa on soils with pH
below 6.
Phosphorus
The form and
availability of soil phosphorus (P) is also highly pH dependent. Plants
take up soluble P from the soil solution, but this pool tends to be
extremely low, often less than 1 lb/ac.
The limited
solubility of P relates to its tendency to form a wide range of stable
minerals in soil. Under alkaline soil conditions, P fertilizers such as
mono-ammonium phosphate (11-55-0) generally form more stable (less
soluble) minerals through reactions with calcium (Ca).
Contrary to
popular belief, the P in these Ca-P minerals will still contribute to
crop P requirements. As plants remove P from the soil solution, the more
soluble of the Ca-P minerals dissolve, and solution P levels are
replenished. Greenhouse and field research has shown that over 90 per
cent of the fertilizer P tied up this year in Ca-P minerals will still
be available to crops in subsequent years.
The fate of
added P in acidic soils is somewhat different as precipitation reactions
occur with aluminum (A1) and iron (Fe). The tie-up of P in A1-P and
Fe-P minerals under acidic conditions tends to be more permanent than in
Ca-P minerals.
Potassium
The fixation of
potassium (K) and entrapment at specific sites between clay layers
tends to be lower under acid conditions. This situation is thought to be
due to the presence of soluble aluminum that occupies the binding
sites.
One would think
that raising the pH through liming would increase fixation and reduce K
availability; however, this is not the case, at least in the short
term. Liming increases K availability, likely through the displacement
of exchangeable K by Ca.
Sulfur
Sulfate (S042-) sulfur, the plant available form of S, is little affected by soil pH.
Micronutrients
The
availability of the micronutrients manganese (Mn), iron (Fe), copper
(Cu), zinc (Zn), and boron (B) tend to decrease as soil pH increases.
The exact mechanisms responsible for reducing availability differ for
each nutrient, but can include formation of low solubility compounds,
greater retention by soil colloids (clays and organic matter) and
conversion of soluble forms to ions that plants cannot absorb.
Molybdenum (Mo) behaves counter to the trend described above. Plant availability is lower under acid conditions.
Conclusion
So, soil pH
does play a role in nutrient availability. Should you be concerned on
your farm? Be more aware than concerned. Keep the pH factor in mind when
planning nutrient management programs. Also, keep historical records of
soil pH in your fields. Soils tend to acidify over time, particularly
when large applications of NH4+ based fertilizers are used or there is a
high proportion of legumes in the rotation.
Recent years
have shown the pH decline occurring more rapidly in continuously
cropped, direct-seeded land. On the other hand, seepage of alkaline
salts can raise the pH above the optimum range. So, a soil with an
optimum pH today may be too acid or alkaline a decade from now,
depending on producer land management.
Prepared by:Ross H. McKenzieResearch Scientist - Soil Fertility/Crop NutritionTelephone: (403) 381-5842
Farm & Forest Can Develop Together According To Scientists
Posted by Unknown in Agriculture and Farming, Fertility of Land, Forest, India, Research and Studies, Soil Issue, Soil Management, Sustainable Agriculture on Sunday, 27 January 2013
Agriculture
and forest can exist in harmony with each other and sustainable
development too can take place provided things are planned in that
manner.
Unfortunately,
lack of coherent and sustainable planning, a result of absence of a
'land use policy' in the country, is not allowing that to happen. As
along as human beings do not break the balance and interfere with
ecology, agriculture and forest need not be in conflict with each other.
This was the opinion of almost every speaker at the inaugural programme of a two-day brainstorming session on 'Agriculture and Forest: Conflicting Domains or Symbiotic Paradigm' organized by the National Bureau of Soil Survey and Land Use Planning (NBSS&LUP) on Tuesday.
S
M Virmani, former chief scientist of International Crop Research
Institute of Semi-Arid Tropics, Hyderabad, said that forest was capable
of giving every thing human beings could ask for including shelter,
food, and medicines but it was our greed that was leading to a situation
of conflict. Giving examples of gradual disappearance of sparrow from
urban ecology and tigers from forests, he said these were manmade
disasters. The man-animal conflict was an example of man encroaching
upon tiger's territory rather than tiger encroaching on human land. He
warned that unless we traced the causes of this conflict. the required
damage control was not possible.
A
K Joshi, principal chief conservator of forests (PCCF), Maharashtra,
spoke about the nature and conflict between people, animal, forest and
agriculture activities and also mentioned the importance of symbiosis of
these activities.
He also spoke about the livelihood opportunities through ecotourism in the tribal belts.
Ram
Prasad, ex-PCCF Madhya Pradesh, explained the role of water management
through forest for agriculture purpose and importance of forest planning
for watershed management to provide maximum benefits to farmers in the
lower reaches. Forest and agriculture both were land based, occupying a
continuum on the landscape and their co-existence was necessary for
sustainable livelihood in the tribal areas, he said.
He
also mentioned that agriculture was the main beneficiary of forest
ecosystem, conservation of forest could provide satisfaction provided
policies were formulated to address specific issues, he added.
Dipak
Sarkar, NBBS&LUP director, stressed on the role of forests in
carbon storage as trees were the biggest source of carbon sequestration.
He pointed out that cutting of forests led to huge soil erosion which
had a devastating effect on both forest ecosystem as well as human life.
Ashok
Sharma, chief general manager of Forest Development Corporation of
Maharashtra, traced the root cause of various problems to improper
policies. He categorically stated that disregarding scientific
principles of management could eventually lead to vegetation anarchy
both in forestry and agriculture. He called for a comprehensive
landscape management policy.
Arun
Chaturvedi, principal scientist and head of land use planning at
NBBS&LUP, spoke on symbiosis of agriculture and forests. He observed
that climate change would affect rainfed agriculture and increase
pressure on the forests.
He stressed on the need for creating awareness among farmers about value of non-timber forest produce.
He
said in erstwhile forested areas, it was not possible to sustain a
family of even 4-5 persons on one or two hectare of land. The income
from agriculture needed to be supplemented with additional income from
forest produce or other ancillary activities like poultry, pisciculture
small ruminant animals etc.
Expert View
*
Since forests are biggest source of carbon-dioxide sequestration,
conscious efforts should be done to increase forest cover without
displacing forest dwellers
* Efforts must be made to minimize global warming caused through agriculture
* Agriculture growth should shift from horizontal to vertical
* Identify faults in existing forest and agriculture development processes and make efforts to rectify them
* Evolve better and scientific policies of land use for sustainable forest and agriculture development
* Develop a land use policy for country
* Increase per hectare productivity of agriculture and diversify agriculture
Times of India
Advantages of Manure Fodders for Growing Crops Faster
Posted by Unknown in Green Manure, Manure and Composting, Silage and Forage, Soil Issue, Soil Management on Friday, 25 January 2013
 |
| Manure exposed to sun and rainwater loses essential nutrients. |
Many small-scale farmers do not use manure properly. Carelessly stored manure can lose half of its nitrogen content.
William Ayako*
No
doubt, manure promotes the growth of all crops. The only problem is
that many dairy farmers lack skills for improved management. This is
shown in a study on methods of manure management on smallholder
peri-urban dairy farms in Bahati division, Nakuru district. The results
of the study, conducted in July, 2005, are significant for other regions
in Kenya too.
A
total of 30 smallholder dairy farmers in the Bahati region were
randomly picked; their farming system is mainly small-scale mixed
crop/livestock type. The farmers kept an average of 1 - 2 mature cows,
mainly of Friesian, Ayrshire and Zebu crosses. The feeding was mainly
“cut and carry” (zero gazing) in stables with planted Napier grass as
the main feed resource and crop residue found within the farm.
It
became clear that smallholder dairy farmers, neglected by policy
makers, could not afford to apply inorganic fertilizers on Napier grass.
The inputs were relatively expensive, and the availability of those
inputs was always untimely. This means that the farmers were therefore
in dire need of skills to improve manure management to boost fodder
production for their dairy cows. This was even more important as the
high human population in the division led to further decline in soil
fertility due to over-cultivation of land.
Soil
degradation as well as poor livestock nutrition and livestock diseases
were responsible for the low milk production. Labor shortage and lack
of capital was evident since over 90% of the farmers in Bahati used
family labor and simple tools to apply manure. Some of the farmers used
bedding from unused maize stalks for compost making. This is very
helpful since the compost takes time to decompose under field conditions
and hence increased the nitrogen ratio.
Improve Napier grass yield
 |
| Young Napier Grass : An Excellent Fodder |
Since
the majority of the farmers stored manure in open heaps for
convenience, the method caused high nutrient losses, estimated at over
30% of nitrogen content when the storage duration exceeded 3 months.
Extended
storage in open heaps further increased losses estimated to be more
than 50% of nitrogen when the storage exceeded 6 months. During the
season of land preparation, planting and weeding of the field crops,
labor became scarce and manure management suffered at the expense of
other activities. Therefore, it was estimated that smallholder farmers
in the division incurred nutrient losses of over 60% in manure nitrogen
due to lack of improved handling and application methods. In other
words, through negligence, farmers reduced Napier yields and hence milks
production and their income.
Recommended methods
The manure application technology, developed by KARI Naivasha, has two options.
•
The farmers on the hill slopes and with less than one acre of land
should use the ‘tumbukiza’ method of manure management on Napier grass.
The system involves digging pits
of about 3x3x3 cubic feet. The pits are spaced at 2 meters apart and
are filled with 3 debes of slurry (a mixture of manure and water), then a
1-foot layer of top soil is added on top of the manure. Thereafter,
6–10 cane cuttings of Napier grass are planted on each pit.
The
tumbukiza method has been known to increase fodder yield by
approximately 30 %. It is advised to plant sweet potatoes or forage
legumes between the pits to increase the quality of forage and to
control weeds.
•
Farmers should also plant Napier grass along the contours using the
Fanya Juu method. In the Fanya Juutrenches, they should apply the
slurry as explained above, then add top soil and plant Napier grass.
This would prevent soil nutrient losses through erosion and secondly, it
would reduce the frequency of additional labor. The most important
advantage is increase in Napier grass yield per given area.
Farmers
in less hilly areas should apply slurry in a shallow trench dug between
the rows of Napier grass and cover with the soil. Although this method
is labour-intensive, it enables better utilization of nitrogen in the
urine and reduces other loses arising from evaporation. Many small-scale
farmers do not use manure properly. Carelessly stored manure can lose
half of its nitrogen content.
Dr. William Ayacko is a livestock scientist at the KARI Naivasha Animal Husbandry Centre
