Laboratory experiments to determine the effects of seeds collected from different parts of the plant on the seed quality of the lentil were carried out from August to September in 2004 and 2005 at the Seed Technology Laboratory, Bangladesh Agricultural Research Institute in Gazipur, Bangladesh. Lentil seeds of three varieties were harvested from different parts of the plant i.e. P1: collection of pods from upper parts of lentil plants, P2: collection of pods from middle parts of lentil plants, P3: collection of pods from lower parts of lentil plants prior to harvesting. All the seeds were stored in earthen pot until conducting the laboratory study. A significant variation was observed in the three varieties of lentil for most of the parameters studied. The highest germination percentage, root length, shoot length, root plus shoot length and vigour were observed in the BARI Masur-4, and the lowest in the BARI Masur-2. Seeds collected from different parts had significant effect on some parameters studied. Collection of pods from middle parts of the lentil plants (P2) recorded the highest germination percentage, root length, shoot length, root plus shoot length and vigour and the lowest moisture percentage. The BARI Masur-4 seeds collected from middle parts of lentil recorded the highest shoot length, root plus shoot length and vigour.
Soil samples were amended with 2ml aliquots of nutrient solution containing 3000 μg or 3333 μg C, 15 μg S and 250 μg N/g soil in the form of D-glucose or cellulose, MgSO47H2O and NH4NO3 and incubated at 26 ± 4°C for 30 days to assess biodynamics of microbial biomass nitrogen and sulfur. A basal dressing of 200 μg P and 250 μg K/g soil in the form of KH2PO4 was applied for each treatment except control. The highest rate of CO2-C evolution was recorded in glucose plus N plus S amended soil which was significantly higher than that obtained from glucose plus N, glucose plus S, glucose and control soil. A similar pattern of CO2-C formation was observed in the cellulose amended soil treated with N and S. The respiration rate in the glucose amended soil was higher than that of the cellulose amended soil. In glucose and cellulose amended soil treated with N and S, the amounts of biomass-C, -N and -S were increased following an increase in the rate of CO2-C evolution. The concentrations of inorganic N and SO4-S were higher in those soils that received N and S than the soils where no N and S were added. The critical N concentrations were ca. 122.5 and 44 mg N/g biomass in cellulose and glucose amended soil, respectively. The critical S concentrations were ca. 12.0 and 8 mg S/g soil in cellulose and glucose amended soil, respectively.
An incubation experiment was carried out in a laboratory at room temperature (28 ± 4°C) for 60 days with four organic materials to assess the biodynamics of microbial biomass nitrogen and sulfur. The organic materials were dustbin waste, poultry litter, sewage sludge and rice straw. The organic materials were added at a ratio of 2 % to the soil. A basal dressing of 200 μg P and 250 μg K/g soil in the form of KH2PO4 was applied to each treatment, except for the control. The highest rate of CO2-C evolution was observed in the rice straw amended soil, which was significantly higher than that of poultry litter, dustbin waste, sewage sludge treated soil and control. Rice straw contributed the highest amounts of biomass-C, -N and -S which were significantly higher than that of poultry litter, dustbin waste and sewage sludge amended soils. The soils amended with sewage sludge, dustbin waste and poultry litter showed N and S mineralization whereas soil amended with rice straw induced N and S immobilization.
The genus Rhizoctonia is one of the most important pathogens and causes serious damage to several crops. A significant amount of rice yield is reduced in most rice growing countries, including those in Asia, Europe, America, and Africa. A considerable number of researchers have studied this topic not only in Japan, but also in the other rice growing countries. However, research activity of the Genus Rhizoctonia is still at the initiation level, and very little information concerning the fungus is available in Myanmar. Therefore, the present study aims to give a preliminary report on the population structures of the Rhizoctonia species that infects rice sheaths in Myanmar. Diseased samples of rice sheaths were collected from April to June of 2007 in the summer rice growing season from the three rice growing areas of Myanmar, namely Mandalay, Pyinmana and Hmawbe. Isolation was conducted by a Water Agar (WA) medium at 25°C for 7 days. A total of 167 isolates were obtained from the diseased rice sheath symptoms; 44 isolates of the R. solani AG-1 IA, 30 isolates of the R. oryzae, and 93 isolates of the R. oryzae-sativae were collected. Preservation of these isolates was conducted on potato dextrose agar (PDA) slant media in test tubes. The cultured tubes were kept at room temperature, and were refreshed every 6 months.
The present study aims to report preliminary results of surveys on water and soil environments and farming systems in Pha Oudom districtof Bokeo province in northern Laos. Field surveys based on interviews and observations were conducted to obtain background information for soil and farming systems. Water quality and climatological characteristics were analysed in order to evaluate the basic conditions of water environments in the area. A global climatic data set of monthly precipitation along with the mean, minimum and maximum temperatures were used for the climatological analyses. The results of the wetness index indicated a seasonal scarcity of potential water resources from October to April. The farming practices were found to depend on the seasonal availability of water resources and the soil characteristics of the area. A typical non-timber forest product (NTFP) of paper mulberry was collected during the non-harvest period, by which farmers earned additional income to their main agricultural products without increasing time between other crops. Ranking of agricultural products in terms of income and farmers' engagement differed both within and between villages. The first priority in animal husbandry was pig, followed by poultry, goat and large animals such as cattle and buffalo. Fisheries were not common among the surveyed villages. Multiple and integrated uses of natural resources such as NTFPs could be an approach used to achieve sustainable agricultural development. Along with the transition from sifting cultivation to sedentary agriculture, an increased commercialization of cash crops and NTFPs would also need to be considered for the profit of local people. Further investigations into biophysical environments, farming systems and socioeconomic conditions are necessary to develop an analytical framework for the mechanisms of the rapidly changing landuse and livelihood in northern Laos.
Incoming solar radiation is one of the main climatic variables, and frequently considered as an input to hydrological model and crop growth model. The present study aimed to develop a preliminary model for estimating daily incoming solar radiation in Gia Lam district, Hanoi, Vietnam. Five empirical models were calibrated based on the relationship between daily incoming solar radiation and each of daily sunshine duration and daily temperature range. All the climatic variables were measured at Hanoi University of Agriculture located in Gia Lam district, Hanoi, Vietnam. The performance of the models was compared with regards to estimation accuracy and characteristics of the models. The best performance for the present data set was found at modified Angström model, and followed by original Angström model, Hargreaves model with linear regression, Hargreaves model with power regression, and original Hargreaves model. The present result suggested the use of Hargreaves model with linear regression in the case where only daily temperature range was available for modelling incoming solar radiation. For the better estimation of incoming solar radiation, it is necessary to calibrate these empirical models based on the climatic observation data at longer period of time.
To develop a productive mass-rearing system for Brontispa longissima, its immature development and adult reproduction were compared among mature leaves of Cocos nucifera, Typha angustifolia, and young leaves of C. nucifera, the ordinary diet for mass-rearing of this insect in the laboratory. Although the immature survival of B. longissima was not different among young and mature leaves of C. nucifera and T. angustifolia, the larvae reared with mature leaves of C. nucifera and T. angustifolia developed significantly faster than those with young leaves of C. nucifera. The adults reared with T. angustifolia were significantly larger, started ovipositing earlier and laid more eggs for 40 days after emergence than those with young leaves of C. nucifera. Considering immature development and adult reproduction, T. angustifolia and mature leaves of C. nucifera would be better diet plants than young leaves of C. nucifera for laboratory rearing of B. longissima.