 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Microbial Ecology in Submerged Soils as Revealed by Using TTC (Triphenyl Tetrazolium Chloride) (Part 2)) ผู้เขียน: Pongsiri Patcharapreecha, Duangsamorn Taja, Hidenori Wada สื่อสิ่งพิมพ์:pdf AbstractA few aspects of microbial lives associating with decomposition of rice straw and sesbania leaf in the submerged three Thai paddy soils (one sandy soil and two clayey soils) were examined rather in detail under a microscope using the TTC technique. Water-soluble substances extracted from these plant debris were confirmed to be preferred substrates for soil microorganisms. Removal of these substances somewhat affected the decomposition process of the plant debris themselves, mode of affection being different between rice straw and sesbania leaf. A succession of microorganisms including protozoa was recognized during decomposition of the plant debris. This succession was considered to proceed from r-strategists to K-strategists. Additional evidence was obtained to support the assumption that sesbania leaf contained some organic compounds toxic to microorganisms and in the initial period of decomposition this compounds were more effective in the sandy soil than in the clayey soils because these compounds were adsorbed by clay particles. Contrary to the widely accepted concept, the decomposition rates of these two plant debris were higher in the clayey soils than in the sandy soil. This may be caused not only by the effect of the toxic substances but also by the difference in microflora. Available information suggested that microbial decomposition of rice straw in the Thai soils were some what different from that in Japanese soils. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Microbial Ecology in Submerged Soils as Revealed by Using TTC (Triphenyl Tetrazolium Chloride), Part 1 : An observation Approach) ผู้เขียน:Pongsiri Patcharapreecha, Duangsamorn Taja สื่อสิ่งพิมพ์:pdf AbstractMicroorganisms associating with decomposition of rice straw and sesbania leaf in the submerged three Thai paddy soils (one sandy soil and two clayey soils) were examined under a micro-scope. The soils were added with water-soluble colorless TTC which was converted into water-insoluble red formazan when it was reduced by emzyme dehydrogenases of microorganisms so that the micro-habitats favorable for active microorganisms and some of the microorganisms themselves were easily recognized. In addition, sulfate reduction and methane formation could be also followed by observing blackened parts of the plant debris and the appearance of methane bubbles, respectively. Colonization of microorganisms on the plant debris started at cut ends, incisions and then extended to inside of plant debris. Decomposition pattern of rice straw was similar among three Thai soils, though its decomposition rate was somewhat lower for the sandy soil than that for the clayey soils. Decomposition of sesbania leaf was more different between the sandy soil and the clayey soils. A lag period in decomposition of sesbania leaf was recognized in the sandy soil but not in the clayey soils. The decomposition rate was clearly lower for the sandy soil than for the clayey soils. In the sandy soil, the number of protozoa were much less populated near sesbania leaf than near rice straw, though in clayey soils such facts were hardly found. Probably, some organic compounds contained in the sesbania leaf might inhibit the growth of protozoa, this effect being unclear in the clayey soils probably because these organic compounds were adsorbed by clay particles. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : A Pot Experiment to Test Effectiveness of The Surface-Placement of Sesbania Debris Prior to Incorporation into The Submerged Soil ) ผู้เขียน:Pongsiri Patcharapreecha, Duangsamorn Taja, Hidenori Wada สื่อสิ่งพิมพ์:pdf AbstractThe surface-placement of sesbania debris prior to incorporation into the submerged soil was previously proposed as a possible technique to avoid the adverse effect of application of sesbania debris on rice seedlings by suppressing accumulation of organic acids in the soil. Effectiveness of this technique was examined by a pot experiment in a green house. The surface-placed of sesbania debris smelt very bed for few days, probably because accumulation of butyric acid in the debris. When the bad smell disappeared and the sesbania debris became dark and soft, incorporation of the surface-placed sesbania debris ded not show the adverse effect on the rice seedlings. In other words, the time suitable for incorporating the surface-placed sesbania debris could be easily determined without using any analytical tools. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Remarkable Enhancement of Growth and Yield of Rice at a Farmer’s Field by Applying Sesbania Debris According to a New Technique) ผู้เขียน:Pongsiri Patcharapreecha, Duangsamorn Taja, Hiroshi Ishida, Hidenori Wada สื่อสิ่งพิมพ์:pdf AbstractAt harvest-time, detailed examination was made on growth and yield of rice growing in a rain-fed farmer’s paddy field to clarify effects of the surface-placement of sesbania debris prior to incorporation into the submerged soil. Four plots were set up in the field. The C plot was applied with ammonium sulfate (12 kg N/rai). The S and 2S plots were applied with sesbania debris at the rate of about 12 kg and 24 kg N/rai, respectively. The Ch plot was unfertilized. As compared with the Ch plot, the green manuring increased culm length, ear number, straw weight, ear weight and yield. This was especially remarkable for 2S plot. Among yield components, ear number and/or grain number per ear greatly contributed to yield increase in the S and 2S plots. Increase in both percentage of selected brown rice and thousand-kernel-weight were contributed to increases in yield in the S and 2S plots also. On the contrary, growth and yield of rice in the C plot was not much different from those in the Ch plot. These results also showed that rice plants in the S and 2S plots were healthy and vigorous in the later growth stage. Uptake of macro-nutrients by rice plants was enhanced by the green manuring but not by application of ammonium sulfate. Implication of these results were discussed. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effects of Surface Placement of Sesbania Debris Prior to Incorporation into the Soil on Growth of Rice and Soil Properties ) ผู้เขียน:Pongsiri Patcharapreecha, Duangsamorn Taja, Hiroshi Ishida, Hidenori Wada3 สื่อสิ่งพิมพ์:pdf AbstractIn a rain-fed farmer's paddy field, sesbania debris was utilized as a green manure according to the previously proposed technique, i.e. the surface placement of sesbania debris prior to incorporation into the submerged soil. The technique was confirmed to be very effective not only in avoiding the adverse effect of the applied debris which in turn enhanced growth and yield of rice but also in improving soil properties. A low input technology was suggested basing on the results of the current and the previous experiments and other available information. |