Effect of a culture of “native” micro-organisms, biochar and biodigester effluent on the growth of maize in acid soils

Lylian Rodríguez, Patricia Salazar and T R Preston

Finca Ecológica TOSOLY, AA48 Socorro, Colombia
lylianr@utafoundation.org

Abstract

A biotest under farm conditions, with maize as the indicator plant, was used to evaluate three additives with potential to ameliorate soil fertility and health: biochar (the residue from gasification of sugar cane bagasse), NM (a culture of native micro-organisms derived from fertile soils on the farm) and biodigester effluent.  The treatments in a completely randomized 2*2*2*2 factorial arrangement with 3 replications were: Soil type (surface soil from a coffee plantation [SC]  or sub-soil [SS]); Biochar (None [NB] or 2% of soil [B]); Effluent (With [E]  or without [NE]); and Native micro-organisms (With [M] or without [N]).  There were three repetitions of each treatment in a completely randomized design. The two types of soil were placed in plastic bags used for germinating coffee (capacity 1.5 liters). According to treatment biochar was mixed with the soil prior to placing it in the bags. Three maize seeds were placed in each bag and according to treatment the culture of NM was sprayed on the soil (50 ml on day of planting the maize and 50 ml 10 days later), followed by biodigester effluent in quantities to provide the equivalent of 50 kg N/ha divided in 10 equal applications. The NM was prepared by mixing fertile soil with rice bran, biochar, sugar cane juice, goat milk yogurt and biodigester effluent.  The maize did not germinate uniformly in the NM treatments, therefore all the maize seeds/plants were removed and new seeds planted 10 days after the last application of NM. The soil in the bags was irrigated as necessary. The maize (after germination 1 or 2 plants were removed to leave only one for the test) was harvested after 50 days of growth and measurements made of above-ground biomass and root development. 

Biochar increased root development but did not affect yield of the above-ground biomass. The NM increased maize foliage growth three-fold and root development two-fold. Effluent increased maize foliage growth by 70% and root weight by 100%. There were cumulative effects of each of the interventions with the combination of biochar, NM and effluent supporting more than ten-fold increases in weights of maize foliage and roots compared with the control treatment of no intervention.

Key words: Amelioration, biotest, EM, gasification, local resources, rice bran sugar cane juice, yogurt

Introduction

The use of a culture of  beneficial micro-organisms to improve soil fertility was pioneered by a Japanese horticulturalist and agriculturist Dr Higa, Professor at the University of Ryukyus, in Japan. He named the culture “Effective Microorganisms – EM” describing it as a cocktail of beneficial bacteria that could be used for soil remediation. Higa’s findings were published in a book (Higa 1991a) and have served as the basis of a wide range of EM-based products that are sold commercially in many countries. Surprisingly, there appear to be few (if any!)  published papers describing experiments in which EM have been used. Most references to EM are in presentations at scientific meetings (eg: Higa 1991b;  Higa and Parr 1994). It is difficult to find information, neither on the exact composition of the various forms of EM that apparently are being used, nor on the ways to prepare them. A typical description of one commercial product is that it contains “five families of micro-organisms: lactic acid bacteria, yeasts, actinomyces, photosynthetic bacteria and fungi”.

Based on the claims made for the commercial products,  two researchers in Latin America (Dr Raúl Botero, Earth University, Costa Rica; and  Dairom Blanco Betancourt,  Indio Hatuey, Cuba) successfully developed “locally produced EM”.  In particular, Dairom Blanco (Personal communication) noted specific benefits from adding  biodigester effluent to the culture media.

Previous experiments conducted in our laboratory (Rodríguez et al 2009) showed that there were synergistic effects on growth of maize from combining biochar (the residue from the gasification of sugar cane bagasse) with biodigester effluent, as additives to an acid sub-soil (pH 4.5). It was therefore hypothesized that adding biochar to the culture media of EM would increase still further the potential value of the microbial inoculum as a soil improver. Another major objective of the research was to develop a product which could be made from materials freely available on a small farm practicing integrated agriculture based on locally available resources (Rodriguez 2009).

Materials and methods

Location

The study was conducted between April and June 2010 in the farm  "Finca Ecológica TOSOLY" located in the village of Morario, Guapota municipality, Santander, Colombia (6 ° 18 'N, 73 ° 32' W, 1500 m) with range of temperature of 15 to 35 °C and average annual rainfall of 1800mm.

Treatments and design

A biotest using maize as indicator plant was conducted according to the general procedure described by Boonchan Chantaprasarn and Preston (2004). The treatments in a completely randomized 2*2*2*2 factorial arrangement with 3 replications were:

Soil type: From coffee plantation (SC) or sub-soil (SS)

Biochar: None (NB) or 2% of soil (B)

Effluent: With (E) or without (NE)

Native micro-organisms: With (M) or None (N)

Materials

Plastic bags and seeding with maize

Polyethylene bags (17 * 23 cm; capacity 1.5 liters) were filled with 1 kg of soil to which had been added 2% (by weight) of biochar (Photos 1 and 2). Maize seeds (n=3) were planted in each bag. After germination 1 or 2 plants were eliminated leaving only 1 maize plant as the experimental unit.

Photo 1. Biochar and soil before mixing.	Photo 2. Biochar and soil after mixing.

 Soils

The fertile soil (SC) was taken from the upper 10 cm layer in the coffee plantation, which was shaded with Guamo (Inga edulis) trees (Photo 3). The sub-soil (SS) was from an area in which the top 1m of top-soil had been removed (Photo4).

Photo 3. Soil being taken from the coffee plantation shaded with Guamo trees.	Photo 4. Sub-soil

Natural microorganisms (NM)

Fertile soil (30 kg), taken in equal quantities from the top 10 cm layer in the coffee plantation of the farm (Photo 4) and in the bamboo grove (Photo 5), was mixed with 25 kg of rice bran and 2 kg of biochar   A separate liquid fraction was prepared from sugar.cane juice (12 litres) mixed with 1 litre of goat milk yogurt and 10 litres of effluent from a biodigester charged with pig manure. The solid and liquid fractions were then mixed together with an additional 5 liters of biodigester effluent to ensure an appropriate texture of the medium (not too wet nor too dry) and finally placed in a sealed 200 litre PVC drum and left to ferment anaerobically.  

Photo 5. Bamboo grove

At the time of initiating the experiment (the mother culture was then 16 months old) the NM extract was prepared by suspending 3 kg of stock culture in 3 kg of water, mixing manually and then filtering through cloth to obtain a dark-colored liquid.

The NM was applied in quantities of 50 ml/bag at the time of planting the maize and again 10 days later. However, it was observed that the maize germination was irregular, especially in the NM treatments. All maize plants were then removed and new seeds planted 10 days after the second application of NM.

Biodigester effluent

The effluent came from a continuous flow biodigester charged with manure from pigs fed a diet of sugar cane juice, rice bran,  minerals and ensiled Taro leaves and stems (Rodriguz and Preston (2009). It contained 700 mg N per litre with 420 mg NH₃-N/litre.  The effluent was diluted with equal parts of water before application at intervals of 10 days in quantities to give the equivalent of 50 kg N/ha over the 50 days of the experiment..

Biochar

The biochar was the residue after gasification of sugar cane bagasse in a downdraft gasifier (ANKUR Ltd, India). It contained 35% ash and 65% carbon with a pH of 9.0 (Rodriguez and Preston 2010).  It was mixed with the selected soil at the level of 2% prior to filling the plastic bags.

Measurements

The maize was harvested 50 days after planting. The height was measured from the base of the bag to the top of the highest leaf. The whole plant was removed from the bag, soil was removed from the roots, and roots and above ground biomass were weighed. The length of the longest root was also measured.

Statistical analysis

The data were analyzed using the general linear model option of the ANOVA program in the Minitab software (2000). Sources of variation were: treatments, biochar, effluent, NM, soil and the interactions biochar*effluent, biochar*NM, NM* effluent and error.

Results and discussion

Results for individual treatments and main effects are shown in Tables 1 and 2 and Figures 1 and 2. Relevant interactions are in Figures 3 and 4. Figures 5 and 6 show the cumulative effects of biochar, native micro-organisms (NM) and biodigestor effluent on above-ground biomass and root growth of maize planted in fertile soils or in sub-soil.

Biochar increased root development but did not affect yield of the above-ground biomass (Table 1). The reason for the lack of effect on maize foliage yield may have been the low level used (2% of the soil) as in most contemporary experiments (Rodriguez et al 2009; Sisomphone et al 2011; Sokchea et al 2011) the minimum level used was 4% of the weight of the soil. The NM had a major effect on maize foliage growth (a three-fold increase) and  on root development (a two-fold increase in root weight).  Application of effluent increased maize foliage growth by 70% and root weight by 100%. 

 There were cumulative effects of each of the interventions (Table 2 and Figures 5 and 6) with the combination of biochar, NM and effluent supporting more than ten-fold increases in weights of maize foliage and roots.  

Figure 1. Effects of NM and biochar on above-ground biomass of maize	Figure 2. Effects of NM on above-ground biomass of maize grown in fertile soil and sub-soil
Figure 3. Effects of NM and biochar on root weight of maize	Figure 4. Effects of NM on root weight of maize grown in fertile soil and sub-soil
Figure 5. Effects of biochar alone, or with NM, or with NM and effluent, on above-ground growth of maize	Figure 6. Effects of biochar alone, or with NM, or with NM and effluent, on root growth of maize

At this stage of the research, carried out under practical farm conditions, it was not possible to identify the possible reasons for the dramatic effect of the NM on maize yield, as on the farm there were neither facilities for identification of the micro-organisms nor for analyses of the chemical composition of the final product.

The main objective was to develop a simple method for preparing the culture of NM using resources available on the farm., so that the technology could be made available to other small scale farmers practicing the integrated use of local resources for production of food and energy (effluent is a byproduct of food consumption by the pigs and the family; biochar is a byproduct of renewable energy production from sugar cane bagasse and forage trees; and the NM uses products/byproducts of several of the farm activities).

Future research will attempt to quantify the effect of the different components used in this first attempt at the production of a ”home-grown” culture of native micro-organisms. 

Acknowledgments

The authors are pleased to acknowledge the .help received in: (i)  establishing the experiment which was done during a training course at the farm for “young researchers” from CIPAV; and (ii) harvesting the maize and recording the results which was done as part of the training course for small-holder farmers from the Choco region of Colombia. 

References

Boonchan Chantaprasarn and Preston T R 2004  Measuring fertility of soils by the bio-test method. Livestock Research for Rural Development. Vol. 16, Art. No. 78. http://www.lrrd.org/lrrd16/10/chan16078.htm

Higa T 1991a An Earth Saving Revolution, English Edition (Translator; Anja Kanal) (Volume 2) (Paperback)

Higa T 1991b Effective microorganisms: A biotechnology for mankind. p.8-14. In J.F. Parr, S.B. Hornick, and C.E. Whitman (ed.) Proceedings of the First International Conference on Kyusei Nature Farming. U.S. Department of Agriculture, Washington, D.C., USA.

Higa T and Parr J 1994  Beneficial and Effective Microorganisms for a Sustainable Agriculture and Environment.. Atami, Japan: International Nature Farming Research Center. pp. 7. http://emproducts.co.uk/downloads/EM.pdf.

Minitab 2000 Minitab Reference Manual, Release 13.31 for Windows. Minitab Inc., USA.

Rodríguez L, Salazar P and Preston T R 2009   Effect of biochar and biodigester effluent on growth of maize in acid soils.  Livestock Research for Rural Development. Volume 21, Article #110.  http://www.lrrd.org/lrrd21/7/rodr21110.htm

Rodríguez L and Preston T R 2010   Gasification of fibrous crop residues and live stock production; essential elements in establishing carbon-negative farming systems. Livestock Research for Rural Development. Volume 22, Article #10.  http://www.lrrd.org/lrrd22/1/rodr22010.htm

Rodríguez Lylian  2009 Integrated Farming Systems for Food and Energy in a Warming, Resource-depleting World. PhD Thesis Humboldt-University, Berlin. http://edoc.hu-berlin.de/dissertationen/rodriguez-lylian-2010-10-12/PDF/rodriguez.pdf

Sokchea H and Preston T R 2011  Growth of maize in acid soil amended with biochar, derived from gasifier reactor and gasifier stove, with or without organic fertilizer (biodigester effluent). Livestock Research for Rural Development. Volume 23, Article #69. http://www.lrrd.org/lrrd23/4/sokc23069.htm

Southavong S and Preston T R 2011  Growth of rice in acid soils amended with biochar from gasifier or TLUD stove, derived from rice husks, with or without biodigester effluent. Livestock Research for Rural Development. Volume 23, Article #32. http://www.lrrd.org/lrrd23/2/siso23032.htm

Received 9 September 2011; Accepted 20 September 2011; Published 10 October 2011

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