Effects of Effective MicroorganismsTM on the growth of Brassica rapa

The effects of Effective MicroorganismsTM, one type of microbial fertilizer commercially sold, on the growth of Wisconsin Fast Plants (Brassica rapa) and on the microbial density in soil were examined for this study. Two controls and three treatments were prepared, and plant height, diameter of stem, biomass of seed pod and plant, and the population of general microorganisms in soil were measured in order to be compared statistically by ANOVA and Dunnett test. Although there was no significant difference in plant height, treatment with EM bokashi plus EM solution resulted in the thickest diameter of stem, followed by the chemical fertilizer. Both seed pod/plant biomass and microbial density showed a maximum response to the EM bokashi plus EM application. This suggests that EM products are effective for the improvement of growth of Brassica rapa and for enhancing the increase of microorganisms in soil. Introduction Farmers have adopted the strategy of increasing crop yields by applying large amounts of chemical fertilizers and pesticides. At present, however, the negative effects of heavy applications of chemical inputs, in terms of production, environment, and quality deterioration are becoming apparent (Nishio, 1996). In 1989, the National Research Council of the National Academy of Sciences issued a report which raised considerable speculation about the future of the chemical-based agricultural production system (Parr, 1994). The ultimate goal of sustainable agriculture is to develop farming systems that are productive, profitable, energy-conserving, environmentally-sound, conserving of natural resources such as soil and water, and that ensure food safety and quality (Parr, 1994). Organic agriculture has much in common with sustainable agriculture. The same stress is placed upon the use of renewable resources, conservation of resources, and the maintenance of environmental quality without using chemical inputs (Poincelot, 1986). For instance, soil amendment with composts is an agricultural practice commonly used to improve soil quality and also to manage organic wastes for a sustainable land use (Piqueres et al, 2005 & Singh, 1995). Microbial fertilizer is one way Organic Farmers are able to increase yield and quality of crops without a large investment of money and labor (Pham, 2004). Moreover, microbial fertilizer can clean the environment and encourage the productive capacity of land by reducing the amount of chemical fertilizer consumption (Pham, 2004). Lynch and Harper (1985) attempted to increase decomposition of straw by microbial application. EM•1® and EM Bokashi are microbial fertilizers, created in Japan over 25 years ago by Dr. Teruo Higa PhD of University of the Ryukyus in Okinawa and marketed by EMRO (EM Research Organization). The basic purpose of EM is the restoration of healthy ecosystem in both soil and water by using three major genera of microorganisms which are found in nature: phototrophic bacteria (Rhodopseudomonas), lactic acid bacteria (Lactobacillus), and yeast (Saccharomyces). EM•1® contains Lactobacillus plantarum, Lactobacillus casei, Lactobacillus Fermentum, Lactobacillus delbrueckii, Saccharomyces cerevisiae, and Rhodopseudomonas palustris. “Bokashi” is a Japanese term generally meaning “obscuring the direct effectiveness”. Today it refers to fermented organic matter because it is used as a product name of organic fertilizer composted from kitchen food waste. The concentration of nitrogen in normal bokashi is much lower than in chemical fertilizer, ranging from 2 to 5% total nitrogen (Nishio, 1996). EM•1® Bokashi is a product made of organic matter, generally rice bran or wheat bran. In Hawaii, Mil run (left over from flour mill) is used. The purpose of this research is to observe the effects of *Effective MicroorganismsTM on the growth of Wisconsin Fast Plant (Brassica rapa) and on the microbial density in soil. Method Artificial soil made from mixing equal amounts of small and fine perlite, and fine peat moss was prepared for this study. Soil was sterilized at 180 oC for 24 hours. Twenty five-cm diameter pots were filled with compressed sterilized soil to within 1 cm of the top. Soil in all pots was damp, but not saturated. Pots were divided into five groups of four pots each. Group one was the negative control with only water added throughout the study. Group two was a second control treated with 30ml/week/pot EM solution sterilized by filtering through a 0.45 um syringe filter. Group three was given 30ml/pot of a standard dose of EM solution (0.001%) weekly. Group four was given manufacturer’s recommend dose of a granulated slow release fertilizer (13-13-13 containing trace elements); group five was given 30ml/week/pot standard EM solution (0.001%) plus 1gm/pot of an organic additive called bokashi, was scattered over the top of the soil in each pot. The bokashi was added per pot and each pot was allowed to sit for two week before sowing the Wisconsin Fast Plant seeds. Pots in all five groups were sown with seeds, three seeds per pot, and pots were place in trays below four 30 watt Gro-Lux fluorescent lamps that were lit 24 hours per day. After germination, seedlings were thinned to two seedlings per pot. Water in the trays under the pots provided water on demand to all plants. Measurements of the plant height, the diameter of stem, and the biomass (final week) of seed pods and above ground stems, leaves, and pods were taken (Chaudhary & Iqbal, 2006). For plant height (cm), measurement were taken every week from the surface of the soil to the top of flower buds. The diameter of stem was measured (mm) on final week about 3 cm above the surface of soil where they were thickest. The dry weight biomass per seed pod and per plant was weighed with a precision of 0.001 g. Plants were dried at 80 oC for 24 hours before weighing. Microbial density within the soil was measured on day 35 by performing a basic dilution series on Tryptic soy agar (1.5% tryptone, 0.5% soytone, 0.5% NaCl, and 1.5% agar). This was performed by weighing 1 g of soil from each pot taken from depth of 3 cm and mixing with 9 ml of sterile phosphate buffer (87%Na2HPO4, 13% NaH2PO4, pH7.0). 100-fold dilutions were performed, with 100 uL samples spread on 15 cm TSA plates (Shipman, 1957, Yanagida & Shinohara, 2005). After incubation, the number of colony-forming units (CFU) per gram was determined to estimate numbers of viable bacterial cells. Data was compared by analysis of variance (ANOVA) and Dunnett test as a post-hoc test (multiple comparisons) to see the differences between controls and treatment groups. Results Table 1: The means of plant height in centimeters with standard deviation in parentheses of each group measured at day 7, 14, 21, 28, and 35. Mean (st.dev) Day7 Day14 Day21 Day28 Day35 Group 1 (negative control) 4.15 (1.12) 13.25 (3.77) 19.00 (3.56) 18.42 (6.35) 18.67 (5.92) Group 2 (control) 4.10 (1.10) 12.75 (3.92) 17.00 (3.54) 17.28 (4.99) 19.25 (5.70) Group 3 (EM treatment) 4.09 (0.94) 13.75 (3.01) 16.40 (0.54) 15.75 (2.37) 16.80 (2.49) Group 4 (Chem. Fertilizer) 3.50 (1.22) 10.00 (2.88) 16.00 (2.58) 12.75 (3.30) 15.00 (3.01) Group5 (EM bokashi) 2.81 (1.31) 8.83 (3.12) 15.5 (6.22) 18.2 (6.22) 18.88 (6.44) By one-way repeated-measures ANOVA, there was no significant difference (p=0.162) of the plant height among those 5 groups throughout this study (Table 1).