Friday, 24 June 2011

Can soils be beautiful?

Well, not sure about soils per se but National Geographic magazine has published some pretty outstanding soil, landscape and farming pictures in an online gallery entitled 'Our Good Earth: The future rests on the soil beneath our feet'

Wednesday, 22 June 2011

Biochar needn't be harmful to earthworms

Studies have found that biochar, added to the soil to help sequester carbon dioxide by removing it from the atmosphere, needn't be harmful to earthworms as had previously been thought. According to the report this emerging tool for combating climate change may cause less harm to some soil animals than initial studies suggested.

Earthworms perform many essential and beneficial functions in the soil ecosystem, including soil structure improvement and nutrient mineralization. However the earthworms' ability to perform these crucial functions can be suppressed when they are exposed to toxic substances.

Researchers and scientists from Baylor and Rice Universities, both in Texas, studied the effects of biochar on the common earthworm. The researchers found that wetting the biochar before applying it to the soil mitigates the harmful effects of biochar to earthworms and the earthworms' avoidance of soil with biochar.

"Because of the high potential for widespread application, it is essential to proactively assess and mitigate any unintended consequences associated with biochar soil enrichment," said study co-author Dr. Bill Hockaday, assistant professor of geology at Baylor. "The results show us that depending on rainfall patterns and irrigation, wetting biochar either before or immediately after soil application would be needed to prevent the disappearance of earthworms and enable their beneficial effects on plants."

The results appeared in the June issue of the journal Soil Biology and Biochemistry.

Monday, 20 June 2011

Improving soils to combat nutrient deficiency

Improving the nutritional content of staple crops, via the soil, can help tackle malnutrition according to the New Agriculturalist.

The lack of essential micronutrients in the diet, such as iron (Fe), zinc (Zn) and vitamin A leads to malnutrition on a grand scale in parts of the developing world leading to child mortality and mental impairment. Every year, an estimated 400,000 children, predominantly in Asia, die from zinc deficiency alone, nearly as many as die from malaria. Lack of zinc can cause diarrhoea, poor growth, and weaker resistance to infections such as pneumonia.

The report argues that increasing micronutrient concentrations in grain through the use of specially enhanced fertilisers could be a fast and cost-effective way to improve nutritional health among cereal-dependent communities.

Nearly half of the world's cereal production takes place on land with inadequate levels of soil-available zinc, reducing crop yields as well as contributing to poor child health and high mortality rates. Biofortification of staple crops with target micronutrients (zinc, iron and Vitamin A) is now a key focus for the Consultative Group on International Agricultural Research (CGIAR), through its HarvestPlus programme.

The report describes how adding zinc oxide (ZnO) or zinc sulphate (ZnSO4) to a standard (NPK) fertiliser boosts grain yields in rice and wheat, with ZnSO4 also significantly enhancing Zn concentration in the grain. Increasing micronutrient levels in the soil, through enriched fertilisers, is recommended as the quickest and most locally-appropriate way to enhance Zn uptake by plants and people, simultaneously improving crop yields and dietary Zn levels. For the full report, visit the New Agriculturalist website.

Thursday, 16 June 2011

Practical ways to reduce food waste

I know that this isn’t strictly a ‘soil and water’ issue but it’s one that is particularly important nonetheless.   If we are to successfully meet the challenges of feeding a growing population while better managing the farmed environment, combating food waste is an absolute priority in ensuring that more of what we grow ends up on our plates.

The January 2011 UK Government Foresight report, ‘The Future of Food and Farming’ estimates that as much as 30% of all food grown worldwide may be lost or wasted before and after it reaches the consumer.   Some estimates have placed this as high as 50%.

One of the recommendations of the report is to halve food waste by 2050, which is considered to be a realistic target.   According to the report, if the current global figure of 30% waste is assumed, this could reduce the food required by 2050 by an amount approximately equal to 25% of today’s production.

A recent report published for the FAO, ‘Global Food Losses and Food Waste’ offers a number of practical solutions which consumers and food supply chains need to adopt in order to make this happen.   Below I have listed the headline problems and solutions which are most relevant to consumers and food chains in the west but the full report, which describes these in more detail, is well worth a read.

In industrialized countries food gets lost when production exceeds demand.
Prevention: Communication and cooperation between farmers could reduce risk of overproduction by allowing surplus crops from one farm to solve a shortage of crops on another.

High ‘appearance quality standards’ from supermarkets for fresh products lead to food waste.
Prevention: Consumer surveys by supermarkets; surveys show that consumers are willing to buy heterogeneous produce as long as the taste is not affected.
Prevention: Sales closer to consumers.  Selling farm crops closer to consumers without having to pass strict quality standards set up by supermarkets would possibly reduce the amount of rejected crops.

‘Disposing is cheaper than using or re-using’ attitude in industrialized countries leads to food waste.
Prevention: develop commercial and charity markets for ‘sub-standard’ products that are still safe and of good taste and nutritional value.

Abundance and consumer attitudes lead to high food waste in industrialized countries.
Prevention: Public awareness to change people’s attitudes towards the current massive food waste.

Tuesday, 14 June 2011

Six easy ways to improve your soil

A new guide by the UK’s LEAF organisation (Linking Environment And Farming), 'Simply Sustainable Soils', contains six easy ways to help farmers improve soil condition. 

The guide explains that there are six simple steps which will help farmers to understand how to improve the performance, health and long-term sustainability of farmland.   As well as soil sampling and mapping to help assess current and improving soil condition, following the six steps will give a clear understanding of its condition and health.  The guide explains how to assess the 1) structure, 2) drainage, 3) compaction, 4) organic matter levels, 5) pH & nutrients and 6) biological health of soil.

In addition to giving clear and practical advice for farmers, the book also highlights the significant global problem of soil erosion.

In South Asia, annual productivity losses are estimated at 36 million tonnes of cereal equivalent, valued at £3,390 million by water erosion, and £1,130 million due to wind erosion – £4.4bn in total.  In the USA the total annual cost of erosion is estimated at £27 billion per year, or about £155 per ha of farmland, and topsoil erosion is also a serious problem in Australia and China.

LEAF also emphasises that whilst it is not on the same scale, soil erosion and degradation in the UK has increased.  Most fields are experiencing erosion rates of up to 1.0 t/ha/yr and with soil regeneration rates in the range of 0.5 – 1.0 t/ha/yr, this is not sustainable.

The easy-to-read and clear guide is available from the LEAF website.

Monday, 13 June 2011

Carbon sequestration in soil

The Carbon Farming Initiative, currently the subject of hot debate in Australia, aims to include agriculture in a developing carbon trading scheme.  The scheme, intended for introduction this year, aims to help farmers and others earn additional income from reducing agricultural emissions of greenhouse gases (GHG) such as nitrous oxide and methane through modifying farm management.  

A recent report, however, suggests that one of the main ways envisaged for farmers to reduce emissions, carbon sequestration through improved soil management, is not as straightforward as was once thought.

The report, in the Weekly Times Now, suggests that storing and building significant or saleable amounts of soil carbon may not be practical in all soils, climates and crop and pasture systems.

According to farm consultant Graham Lean, "soil carbon is probably not going to be a great source of carbon storage.  And if we lock-up resources for it, we might be locking up even more valuable nutrients than carbon, such as phosphate and others."

However, other carbon sequestration measures and practices that reduce emissions could help.  Carbon sequestration by trees could generate increased agroforestry incomes, and decreasing methane emissions by livestock could decrease carbon outputs.

But carbon and nutrient cycles are strongly linked and farmers need to think about how they balance inputs, from crop production and residue management, with outputs released during soil decomposition.  CSIRO's land and water expert Dr Lynne Macdonald said that while maximising inputs would maximise carbon stored in soil, farmers needed to understand the whole system and realise carbon and nutrient cycling were tightly tied. 

She did say that soil carbon had a big part to play in sustainable agriculture and a place in soil function in structure and chemical aspects, but "we have to think of the bigger picture – carbon and nutrient cycling – not just carbon alone."

"Carbon is bound to nitrogen and phosphorus and other elements, and has come from plant material," Lynne said.  "It comes as a package, because carbon is bound to nitrogen and phosphorus during plant growth, then when it comes back into the soil they are bound and if you turnover (decompose) the organic matter you get mineralisation of the nutrients."  This mineralisation leads to the loss of these nutrients.

"Whereas if it doesn't turn over and you keep it there then those nutrients remain bound.  As a consequence of holding carbon there, [it] will [also] be holding nutrients."

Thursday, 9 June 2011

Agro-ecological farming

A recent report by the United Nations explores the role that agroecology can play in contributing to food security.  According to the report, ‘agroecology is the “application of ecological science to the study, design and management of sustainable agroecosystems”.   It seeks ways to enhance agricultural systems by mimicking natural processes, thus creating beneficial biological interactions and synergies among the components of the agroecosystem.   It provides the most favourable soil conditions for plant growth, particularly by managing organic matter and by raising soil biotic activity.’

The report states that agroecology provides many agricultural benefits via improving soils.   It does this by improving organic matter and by raising soil biotic activity.   The principles of agroecology include improved nutrient recycling nutrients and reduced energy inputs, and diversifying farm biodiversity – from crop and livestock species to soil microbes.

As well as an emphasis on soils, agroecology also seeks to integrate crops and livestock, diversify species and genetic resources and focus on interactions and productivity across the agricultural system, rather than focusing on individual species.

The system is highly knowledge-intensive but supports the development of drought resistant agricultural systems (including soils, plants, agrobiodiversity, etc.), not just drought-resistant plants.  In addition, agroecology delivers advantages that are complementary to better known conventional approaches such as breeding highyielding varieties.  These factors demonstrates its relevance to modern agricultural systems and objectives, as well as to traditional, smallholder agriculture.

Its focus on increasing crop diversity supports the increased use of nitrogen-fixing plants, including trees, to reduce reliance on external inputs.  It can therefore contribute to delinking food production from a reliance on fossil energy as well as contributing to climate change mitigation, both by increasing carbon sinks in soil organic matter and above-ground biomass, and by avoiding carbon dioxide or other greenhouse gas emissions from farms by reducing direct and indirect energy use.

Tuesday, 7 June 2011

Fungi and farming

Another story which might be of interest to biological farming practitioners – American and Swiss researchers have highlighted the role that symbiotic plant–fungi relationships can play in feeding a growing population, without the need for a corresponding increase in the use of mineral fertilisers. 

The report, in Science Daily, describes how the researchers have been looking at mycorrhizal fungi which lives in the soil and interacts with plant roots.  Where these symbiotic relationships exist, plants tend to grow larger because the fungi acquire and make available for use by the plant the essential nutrient phosphate.

Phosphate is a key ingredient in many fertilisers but imported supplies can be difficult or expensive to obtain, especially by farmers in developing countries.  Over-application of phosphates can cause water pollution problems - phosphate is one of the main trigger chemicals that can cause algal blooms in surface waters which result in considerable ecological damage.

According to Science Daily, while mycorrhizal fungi typically only grow on the roots of plants, recent biotechnological breakthroughs now allow scientists to produce massive quantities of the fungus that can be suspended in high concentrations in a gel for easy transportation.  The researchers are currently testing the effectiveness of this gel on crops in the country of Colombia where they have discovered that with the gel they can produce the same yield of potato crop with less than half the amount of phosphate fertilizers.

Monday, 6 June 2011

Agriculture and the Green Economy

Global agriculture coalition Farming First has produced a series of graphics which clearly demonstrate the role of agriculture in helping to address the global problems of poverty and environmental degradation through building resilient economies and improving sustainability.

Section 6 in ‘Agriculture and the Green Economy’ highlights the potential losses that agriculture could face as a result of climate change…

…while highlighting the role that it could have in reducing carbon emissions:

What fascinated me were the graphics relating to soil degradation caused by humans, which has resulted in 1035 million hectares of land worldwide suffering from poor soils as a result of human activity.

But the flip side of this is the benefits that conservation agriculture (maintaining ground cover, minimising soil disturbance and cultivations, and increasing crop diversity via rotation) can bring, as shown in this graphic relating to Ghana.  Switching to conservation tillage reduced annual per-hectare soil loss from a staggering 313 tonnes to less than two, and reduced water runoff by almost 99%.