Friday, December 20, 2013

Biochar application to Soil

     The effectiveness of applications of composts, animal manures or mineral fertilizers are known to vary significantly whether they are incorporated or surface applied, banded or broadcast (Gherardi and Rengel, 2003), and similar responses can be expected to the method of biochar application. The biophysical responses to the way in which biochar is applied have to be considered, as well as technical feasibility, economic constraints and safety. 



Compost and Biochar

Faster & hotter composting – Reduce Nitrogen loss by up to 50%
Reduce compost emissions – Locks up minerals and nutrients
Makes better quality compost – Reduces compost smells

The basic rule of making a good batch of compost is having the right ratio of carbon and nitrogen. Carbon is classed as any dead or brown biomass like brown leaves, woody mulch, sticks, paper, brown dry grass. Nitrogen is anything green or fresh, kitchen scraps, green grass clippings, fresh animal manure, weeds or anything freshly cut from your garden.
A good carbon nitrogen ratio is 25 parts of carbon to 1 part nitrogen. Have a bucket full of Biochar next to your compost bin, when you add a layer of nitrogen sprinkle two big hand fulls of Biochar over the layer so you end up with the fixed carbon Biochar spread evenly through your compost.
Compost activators will help get the compost bin cooking, some common activators are human urine, yoghurt, worm liquid, compost tea, molasses, honey or a bucket full of compost from your last batch.
Biochar added into composts does not rot or break down, it will bond to nutrients, minerals and will reduce nitrogen loss.


     For example, the properties of fineness (‘dustiness’), spontaneous combustion risk, occasional health risks and very low packing density of biochar may provide specific challenges for safe and cost-effective application to soil. Agricultural productivity is often reported to increase with biochar application to soil, but variability is high and it is not yet clear under what soil and climatic conditions and plant species high or low yields can be expected (Lehmann and Rondon, 2006).




     The type of biochar also plays an important role in its effectiveness, and is itself a function of the type of feedstock and production conditions. Therefore, yield responses are currently difficult to predict, and global patterns need to be identified to move towards an understanding of the crop production potential using biochar.


Biochars produced from different feedstocks (coloured circles) and at different temperature vary in their properties. (source: http://www.soilquality.org.au/factsheets/biochar-for-agronomic-improvement)


Purpose of biochar application
     The purpose of applying biochar to soil mainly falls into four broad categories:
1 -agricultural profitability;
2- management of pollution and eutrophication risk to the environment;
3- restoration of degraded land; and
4 -sequestration of C from the atmosphere.




1- Agricultural profitability
     Reduction of soil acidity, improvements to soil cation exchange capacity (CEC) and pH, water-holding capacity, and improved habitat for beneficial soil microbes are most likely the primary causes of productivity improvements. While some information exists about increases in productivity, very little information is available on profitability. Improved profitability requires costs of improvement to be sufficiently lower than the value of the improved productivity. The technology of biochar use is generally at too early a stage to accurately obtain costs of application.


Cation exchange capacity of biochars as a function of feedstock and in comparison with common soil clay minerals; CECof biochar increases with time by up to orders of magnitude (Krull et al., CSIRO). (source: http://www.soilquality.org.au/factsheets/biochar-for-agronomic-improvement)


2- Managing pollution and eutrophication risk
     Eutrophication is commonly considered as one major aspect of global environmental degradation (Nixon, 1995). From an environmental point of view, it is important to intercept leachable nutrients and pesticides from soil to reduce eutrophication and pollution risks in adjacent water bodies, as well as to reduce the need for fertilizer application that would be required to compensate for such nutrient losses. Biochar shows good evidence for adsorbing nutrients such as phosphate and ammonium (Lehmann et al., 2003; Lehmann, 2007) that may cause eutrophication, as well as adsorbing pesticides before they enter local water sources (Takagi and Yoshida, 2003). 




     Location of the biochar within the root zone is required for the interception of nutrients leached to lower soil depths, and deeper application may be desirable. However, nutrients transported by overland flow may require biochar application close to the surface in buffer zones around water bodies at risk in order to maximize contact between runoff and biochar. Therefore, different environmental management techniques require different application methods.




3- Re-vegetation of degraded land
     Re-vegetation efforts for degraded lands may use biochar as a carrier for beneficial soil microorganisms, for improved CEC, and possibly for soil aggregation and water-holding capacity. Since re-vegetation includes reclamation of denuded landscapes, biochar application offers the ability to enhance soil functions in advance of accumulation of plant litter that would otherwise provide the source of soil organic matter under climax vegetation. The scale of re-vegetation and the availability of labor will influence the methods of application. In some instances, such as during the reclamation of mine spoils, it may be necessary to rebuild the entire soil through thorough mixing.





4- Sequestration of C from the atmosphere
     Most carbon in the soil is lost as greenhouse gas (carbon dioxide, CO2) into the atmosphere if natural ecosystems are converted to agricultural land. Soils contain 3.3 times more carbon than the atmosphere and 4.5 times more than plants and animals on earth (1). This makes soils an important source of greenhouse gases but also a potential sink if right management is applied. The use of crop residues for bio-energy production reduces the carbon stocks in cropland. Further the dedication of cropland to bio-fuel production increases the area of cultivated land and thus carbon loss from soils and vegetation.


     Pyrolysis of waste biomass can generate fuels and biochar recalcitrant against decomposition. If biochar is returned to agricultural land it can increase the soil’s carbon content permanently and would establish a carbon sink for atmospheric CO2. In this case the use of crop residues as a potential energy source may improve soil quality and reduce greenhouse gas emissions in a complementary not competing way. Biochar is proposed as a soil amendment in environments with low carbon sequestration capacity and previously depleted soils (especially in the Tropics). 


  1. Extracting fossil fuel from the earth and burning it puts CO2 into the air.
  2. Growing biomass pulls COfrom the air and incorporates it into itself.
  3. When the plants die, they decompose and the CO2 returns to the atmosphere.
  4. As an alternative to decomposition, the biomass is pyrolyzed.
  5. The biochar does not decompose and so stays out of the atmosphere.


    From previous studies it is known that soil biochar amendments increase and maintain soil fertility (2) and the human-made Terra Preta soils in the Ama-zon prove that infertile soils can be transformed into fertile soils and long term carbon enrichment is feasible even in environments with low carbon sequestration capacity (3).

Tuesday, December 17, 2013

有機稻間鴨隊 (Duck - rice organic farm)

林憲德(2007)指出:「生態金字塔最底層是支撐萬物的土壤,意即土壤和微生物活動是生態環境的基盤,然而,無論處於生態金字塔的何種層級,均必須仰賴陽光、大氣、水、表土等四項環境因子而存活,其中,又以水和表土深受人類開發活動的威脅,尤其城鄉建設對水與表土環境的破壞更是嚴重。但是如果沒有良好的表土,則綠色植物就無法好好生長,動物自然日趨稀少,整個生態系皆會受到影響,因此表土幾乎可喻為「生物之母」。」

  然而,使用生物碳(英語:Biochar)即是一種可以改變土壤的方式,因為生物碳可以捕捉與清除大氣中的碳,將它轉化成非常穩定的形式,並儲存在土壤中達數千年之久,因此可以捕捉大氣中的一氧化二氮及甲烷,大幅減少溫室氣體,亦能增加20%的農業生產力,淨化水質,減少化學肥料的使用,因此生物碳亦稱為農業碳(英語:Agrichar)。

  大有社區則是台灣第一個以生物碳使用於農業用途的地方,藉由生物碳改良土壤,幫助植物生長,以及碳收集、儲存使用、吸附壞的微生物等功效,讓大有社區的土壤日益肥沃與健康,而產出的稻米自然健康無毒,因此也讓大有社區的金碳米成為大有社區最著名的產品,目前除了直接販售外,也已初步打造為伴手禮品,甚至已將生物碳製成手工香皂,近期即將販售。

  大有社區理事長吳素秋表示,使用生物碳後,不僅產出的稻米有機無毒、產量明顯增加,連居住於附近居民的的身體也越來越健康,而大有社區也持續與屏東科技大學環境工程學系的師生們進行研究,將產學結合,期望能製造出更有效益的生物碳。




    (Google translation)  Hsien-Te Lin ( 2007 ) noted: " ecological bottom of the pyramid is to support all of the soil , meaning soil microbial activity and the ecological environment of the base plate , however , no matter what level in the ecological pyramid , must rely on the sun, air, water , topsoil and other environmental factors and four survived among them, the water and topsoil threatened by human development activities , especially in urban and rural construction and destruction of topsoil water environment is serious , but if you do not have good topsoil , the greens will not take growing increasingly scarce natural animal , the entire ecosystems are affected , so topsoil almost called "the biological mother ." "

    However, the use of biological carbon ( English : Biochar) that is a way you can change the soil , because the biological carbon capture and remove carbon from the atmosphere , it will be transformed into a very stable form and stored in the soil for thousands of for a long time , so you can capture atmospheric nitrous oxide and methane, a significant reduction in greenhouse gases by 20% can also increase agricultural productivity , water purification, to reduce the use of chemical fertilizers , and therefore also known as agricultural biochar carbon ( English : Agrichar ) .

    Great community is Taiwan's first bio- carbon for use in agricultural applications where biochar soil improvement by helping plant growth , as well as carbon capture , storage, use , adsorption bad microbes and other effects , so that the soil a great community increasingly fertile and healthy , while the output of rice natural health non-toxic, so let Kim carbon meter great community to become a great community 's most famous product , with the exception of direct selling , but also has initially build for souvenirs gifts, even biochar has been made ​​of handmade soap , recently sold forthcoming .

    Great community chairman Wu Suqiu said that after the use of biological carbon , not only the output of non-toxic organic rice production increased significantly, even the residents living in the vicinity of the body is also getting healthy , and a great community has continued and Pingtung Technology Department of environmental Engineering, University teachers and students to conduct studies combining production , hoping to create a more effective biological carbon .



https://www.facebook.com/pages/%E6%9C%89%E6%A9%9F%E7%A8%BB%E9%96%93%E9%B4%A8%E9%9A%8A/524331300942863

Monday, December 16, 2013

Biochar from charcoal production and recycling of agricultural and forestry wastes

     Worldwide, 41 Mt of charcoal are produced annually for cooking and industrial purposes (Lehmann and Rondon, 2006). Most of this production is located in developing countries (40 Mt in 2002) rather than developed countries (1 Mt), with Africa being the highest producer (21 Mt) in comparison to South America (14 Mt) and Asia (4 Mt). Charcoal production is often detrimental to the environment, as it leads to deforestation and air pollution. Yet, most developing countries have few alternatives to charcoal production for household fuel. However, significant improvements are possible with viable alternatives as far as wood production, charcoal production with respect to human health and use of charcoal waste is concerned. 




     Additionally, it has been argued that use of charcoal as a fuel replacing wood leads to lower levels of household indoor pollution and an associated reduction in mortality (Lehmann and Rondon, 2006). For industrial purposes and in large-scale commercial operations, options for clean and efficient charcoal production exist. 


    Charcoal wastes may however, be of regional importance where small-scale producers dominate the market such as in most parts of Africa, in rural areas in South America and Asia. Charcoal waste can be applied as bio-char to agricultural soils (including the fields where the trees are grown for charcoal production) and turned into a valuable resource for improving crop yields on acid and infertile tropical soils where nutrient resources are scarce (Lehmann and Rondon , 2006).




Recycling of agricultural and forestry wastes
    In many agricultural and forestry production systems, waste is produced in significant amounts from crop residues such as (i) forest residues (logging residues, dead wood, excess saplings, pole trees); (ii) mill residues (lumber, pulp, veneers); (iii) field crop residues; or, (iv) urban wastes (yard trimmings, site clearing, pallets, wood packaging). Other industry and municipal residues could potentially be a suitable and quantitatively important source of bio-char.




    Many of the forestry and agricultural residues can be used to produce bio-char and applied to agricultural soil both to sequester C and to improve the production potential of crops. In many cases, these waste materials have little value and their disposal incurs costs. Today large amounts (more than 50% of total available residues in the U.S.) can be acquired for less than $ 30 per ton of biomass. Other opportunities exist to utilize residues from pulp mills, from eucalyptus plantations to combat salinization and obtain eucalyptus oil, or as an alternative to garbage incineration.  


BIOCHAR, WHEN USED FOR COOKING, IS MADE OUT OF ORGANIC HOUSEHOLD AND CROP WASTE. Source: http://stewards.snre.umich.edu/article/starting


     Not all agricultural waste materials are suitable to produce bio-char, including many field or vegetable crop residues with the notable exception of rice husks, which has high concentrations of silica entrapping C during combustion. Rice husks are typically regarded as a waste product, but can be used to sequester C by producing bio-char. Global rice paddy production is 0.589 Pg yr−1. From this, we calculate the sequestration potential to be 0.038 PgCyr−1 (calculated estimating 32% husk, 38% C concentration, and 53.5% conversion from husk C to bio-char C). 



     Other crop residues such as nutshells (e.g., groundnut, hazelnut, macadamia nut, walnut, chestnut, coconut) but also bagasse from sugar cane processing, olive or tobacco waste are suitable and are in some locations available in large quantities. (Lehmann and Rondon, 2006).



 Bean and corn crop grown without biochar Photo Credit: David Guerena


Bean and corn crop grown with biochar Photo Credit: David Guerena


Benefits to the agricultural sector and waste management
    The agricultural sector can benefit from biochar in two ways: soil improvement and animal and crop waste disposal. Soil improvement, and therefore increased productivity, can be the driver behind biochar production and use. Since 1980, field trials have been taking place around the world experimenting with the application of biochar types on specific soils.  


     The type of biochar varies with biomass type in many cases rice, wood or bark has been used and production parameters, such as the rate of pyrolysis and kiln size. In most of the studies, acidic soils have been the subject of research, and these have generally been in tropical or semi-tropical regions. Experiments have also employed differing treatments, applying relatively more or less biochar, with and without the use of other fertilizers.




     Results of trials have ranged from no increase in productivity (the case of banana plantations in Brazil) to as much as a 151 % increase in soybean yield in one project. In many cases, it was noted that soil acidity was reduced and mineral uptake increased, with residual effects sometimes lasting through to the following season or two. Research is still required into the use of biochar for pastures or tree plantations, and for soils in dry and/or temperate regions.  



     A second benefit of biochar production to the agricultural sector (and some industries, such as the paper industry) is the fact that it uses organic waste. Left to accumulate, animal and crop waste can contaminate ground and surface waters. Waste management practices are aimed at preventing such contamination, but they can become costly. Biochar presents an attractive alternative if the economic costs can be kept below those of waste management. 





     By accepting organic material as its input, the biochar production process transforms waste into a resource. The pyrolysis process reduces the weight and volume of the feedstock, and by operating at a temperature above 350°C, it removes potential pathogens that can be a problem if directly applied to soils. Green urban waste and waste from some industrial processes, such as paper milling, can also be used (Talberg, 2009).

Thursday, December 5, 2013

Biochar manufacturing process conditions.

Temperature, heating rate and heating time
     For the same feedstock, biochar yield is highly dependent upon the conditions under which pyrolysis is carried out; namely, temperature, heating rate, heating time and particle size (Shafizadeh, 1982;Williams and Besler, 1996; Demirbas and Arin, 2002; Uzun et al., 2006; Tsai et al., 2006).While it is well documented that biochar yield decreases with increasing temperature and that the yield temperature relationships are different with different feedstocks (Horne and Williams, 1996; Williams and Besler, 1996; Tsai et al., 2006).

Source: http://english.issas.cas.cn/rh/rp/201101/t20110107_64202.html


    Depending upon the operating conditions, the complex and varying changes of biomass during pyrolysis affect both the composition and chemical structure of the resulting biochar, with significant implications for nutrient contents and, especially, nutrient availability to plants. Changes in the composition of biochars during pyrolysis of organic matter using molecular techniques indicate a gradual decrease in the amounts of OH and CH3 and an increase in C=C with increasing temperature (150°C to 550°C), suggesting a change from aliphatic to aromatic C structure of the biochar.



      In contrast, biochars formed at lower temperatures (300°C to 400°C) are only partially carbonized, with high H/C ratios and O contents, and have a lower surface area. Consequently, low temperature biochars are found to have higher amounts of acid–basic surface functional groups. Therefore, increasing temperature during pyrolysis results in changes in the molecular composition, as well as changes in biochar charge properties.


     Biochars containing large proportions of mineral matter (ash) produced at low temperatures also have a much greater concentration of sub-grain boundaries and defects on the surface than the same biochars produced at high temperatures. Mineral matter in low temperature biochar is more likely to dissolve since these defects are centers for reactions with liquids and gases. These changes should have effects on the total nutrient content as well as their availability.


Biochar
Ashes

    Porosity of biochar significantly increases between 400°C and 600°C, and may be attributed to increases in water molecules released by dehydroxylation acting as pore-former and activation agent, thus creating very small (nanometer-size) pores in biochar (Bagreev et al., 2001).

    Biochar production cannot be properly discussed without first distinguishing it from char and charcoal. All three forms of carbonaceous material are produced from pyrolysis; the process of heating carbon (C) - bearing solid material under oxygen (O2)-starved conditions. Char is defined here as any carbonaceous residue from pyrolysis, including natural fires. Thus, char is the most general term to employ in scientific descriptions of the products of pyrolysis and fires, whether from biomass or other materials. Charcoal is char produced from pyrolysis of animal or vegetable matter in kilns for use in cooking or heating.


     Biochar is carbonaceous material produced specifically for application to soil as part of agronomic or environmental management. No standard currently prescribes the composition or preparation of biochar to distinguish it from charcoal produced as fuel. However, understanding of what makes for ‘good’ charcoal in agronomic and environmental management applications will inevitably encourage separate designations for charcoal and biochar. Although C is the major constituent of charcoal, its exact composition and physical properties depend upon the starting material and the conditions under which it is produced.

     Charcoal contains 65 to 90 per cent C with the balance being volatile matter and mineral matter (ash) (Antal and Grønli, 2003). Superficially, charcoal resembles coal, which is also derived from vegetable matter; indeed, the word charcoal may have originally meant ‘the making of coal’ (Encyclopedia Britannica, 1911).



Source: http://techalive.mtu.edu/meec/module19/Page3.htm


    However, the geological processes from which coal is derived are quite different from charcoal-making, resulting in important differences in chemical composition, porosity and reactivity. Charcoal is readily generated in open fires, whether forest fires or campfires. Thus, it was available to early humankind whose first apparent use of it was in the creation of spectacular cave paintings during the last Ice Age (Bard, 2002).

Lascaux Cave Paintings - Horse: Drawn 10,000-15,000 B.C.


Chauvet Cave in the valley of the Ardèche River in France is filled with paintings, engravings and drawings created more than 30 000 years ago, of cave lions, mammoths, rhinos, bison, cave bears and horses. It contains the earliest known cave paintings, as well as other evidence of Upper Paleolithic life. It is situated on a limestone cliff above the former bed of the Ardèche River. The cave was first explored on December 18, 1994. As well as the paintings they discovered fossilised remains, prints, and markings from a variety of animals, some of which are now extinct.  Source: http://donsmaps.com/chauvetcave.html

    Charcoal eventually found application in other fields, including agronomy, medicine, metallurgy, pyrotechnics and chemical manufacture. However, its largest application has always been in the preparation of smokeless fuel for cooking, residential heating, smelting and steel making. The process of charcoal making removes most of the volatile matter responsible for smoke during burning. Charcoal is a relatively clean burning fuel that represented an important innovation in the controlled use of fire. Biochar as a C sequestration agent and soil amendment, on the other hand, is still poorly understood.