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Photo 1. Soil |
Photo 2. Sand |
Photo 3. Bio-char |
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MEKARN MSc 2008-10 |
Miniprojects |
Nowadays, fertilizer is very important in agriculture, especially with poor soil. Moreover, the price of the fertilizer is more and more expensive so, using another resource to replace fertilizer is very important for poor rural farmers. Bio-char is the product of biomass pyrolysis that not only sequesters carbon when applied to soil, but also improves soil quality dramatically.
The measurement of the fertility of soils is usually done by chemical analysis for plant nutrients such as nitrogen (N), potassium (K), phosphorus (P) and trace elements, as well as physical measurements of soil structure. Such analyses require access to a laboratory and this is not feasible for most farmers, especially those with limited resources. Planting some indicator plants in the soil and measuring their growth and production is one way to measure fertility of soils in an indirect way (Nguyen Phuc Tien et al 2003).
Besides, bio-char also has positive effects in both reducing emissions and increasing the sequestration of greenhouse gases. The production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production (Lehmann et al 2006).
Higher nutrient availability for plants is the result of both the direct nutrient addition by the bio-char and greater nutrient retention (Lehmann et al 2003).
Bio-char additions not only affect microbial populations and activity in soil, but also plant–microbe interactions through their effects on nutrient availability and modification of habitat. Rhizobia spp. living in symbiosis with many legume species are able to reduce atmospheric N2 to organic nitrogen through a series of enzymatic reactions (Giller 2001).
However, there is little information on the most appropriate level of biochar to add to the soil. This will be studied in the following experiment.
Different concentrations of bio-char in the soil will have different effects on the growth of plant.
To measure fertilizer value of bio-char which came from Colombia by using maize as indicator plant.
The experiment will be designed as randomized complete block (RCB) 2*5 factorial design with ten treatments and two replications of each. The factors are:
Five treatments are five levels of biochar (0, 2, 4, 6 and 8%) mixed with soil only. Other five treatments are mixtures of 50% soil:50% sand mixed with five levels of bio-char (0, 2, 4, 6 and 8%)
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Table 1: The treatments |
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Levels of bio-char in 100% soil |
Levels of bio-char in 50% soil |
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0% |
2% |
4% |
6% |
8% |
0% |
2% |
4% |
6% |
8% |
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S-0 |
S-2 |
S-4 |
S-6 |
S-8 |
SS-0 |
SS-2 |
SS-4 |
SS-6 |
SS-8 |
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Table 2. Experiment layout |
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Block 1 |
S-0 |
SS-2 |
S-6 |
SS-0 |
S-4 |
S-2 |
SS-8 |
SS-6 |
S-8 |
SS-4 |
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Block 2 |
S-8 |
S-6 |
SS-2 |
S-4 |
S-0 |
SS-6 |
SS-0 |
S-2 |
SS-4 |
SS-8 |
S: Soil
SS: Mixture (50% sand with 50% soil)
The soil (rich soil) where earthworms live is collected in the farm of Kampong Cham National School of Agriculture (Photo 1). The sand is also collected from the farm of Kampong Cham National School of Agriculture (Photo 2). The biochar was produced in Colombia, from a gasifier using sugar cane bagasse as the fuel (Photo3).
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Photo 1. Soil |
Photo 2. Sand |
Photo 3. Bio-char |
Ten treatments will be designed with 5 levels bio-char which will be mixed with soil or mixture (50% soil and 50% sand). They will be put into plastic bags (two liters capacity) which have many holes around so the excess water can go out. Then, 3 seeds of maize will be planted in each bag according to the experimental layout in Table 2. Water will be applied uniformly to all bags every morning and evening and observations made of germination and growth of the plants. When the seeds germinate 1 or 2 plants will be removed to leave only one seedling in each bag.
The soil and sand will be analysed for the dry matter (DM), organic matter (OM), N and pH; the bio-char will be measured only for DM and organic matter (OM) at the beginning. The height of the plants will be measured every 5 days over a total period of 28 days. After 28 days, the plants and roots will be removed from the bags, washed free of soil, and weighed 30 minutes later, the green parts (leaves and stems) and the roots separately.
The chemical analyses will be done following standard procedures according to the Association of Official Analytical Chemists procedures (AOAC 1990), except for DM which will be determined by micro-wave radiation (Undersander et al 1993).
The data will be analyze by Analysis of variance (ANOVA) using the General Linear Model (GLM) procedure of the Minitab software (version 13.3) to determine growth rate in height of maize. The sources of variables in the model are: Soil type, Levels of bio-char, interaction Soil type*biochar level and error. The Tukey test in the Minitab software will be used to separate mean values that differ when the F-test is significant at P<0.05.
AOAC 1990 Official methods of analysis. Association of Official Analytical Chemists, Arlington, Virginia, 15th edition, 1298 pp.
Giller, K.E 2001 Nitrogen Fixation in Tropical Cropping Systems, 2nd ed., CAB International, Wallingford.
Lehmann J, Gaunt J and Rondon M 2006 Bio-char sequestration in terrestrial ecosystems – a review, Mitigation and Adaptation Strategies for Global Change (2006), DOI: 10.1007/s11027-005-9006-5.
Lehmann, Johannes, and Jose Pereira da Silva Jr., Christoph Steiner, Thomas Nehls, Wolfgang Zech and Bruno Glaser 2003 Nutrient availability and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin: Fertilizar, manure and charcoal amendments, plant soil, 249, 343-357.
Minitab 2003 Statistical software Version 13.31.
Nguyen Phuc Tien, Ngo Tien Dung, Nguyen Thi Mui, Dinh Van Binh and Preston T R 2003: Improving biomass yield and soil fertility by associations of Flemingia (Flemingia macrophylla) with Mulberry (Morus alba) and cassava (Manihot esculenta) on sloping land in Bavi area. In: Proceedings of Final National Seminar-Workshop on Sustainable Livestock Production on Local Feed Resources (Editors: Reg Preston and Brian Ogle). HUAF-SAREC, Hue City, 25 – 28 March, 2003. Retrieved September 23, 2003, from http://www.mekarn.org/sarec03/tienbavi.htm
Undersander D, Mertens D R and Lewis B A 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154.
