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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Plant Density and Nitrogen Fertilizer Rate on Growth, Nitrogen Use Efficiency and Grain Yield of Different Maize Hybrids under Rainfed Conditions in Southern Vietn ผู้เขียน: Dinh Hong Giang,  ดร.เอ็จ สโรบล, ศาสตราจารย์ , ดร.สุตเขตต์ นาคะเสถียร, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractPlant density (PD) and nitrogen (N) fertilizer are considered the most important crop management practices in improving maize grain yield. Two identical field experiments in Vietnam, in Ba Ria and Dong Nai provinces, were conducted in the wet season 2011 to study the effects of PD and the N fertilizer rate on two maize hybrids. The experiment was laid out in a split-split plot in a randomized complete block design with three replications. Two maize hybrids, NK7328 and LVN10, constituted the main plots and three PD values (57,000, 71,000, and 84,000 plants.ha-1) were the subplots. Five N rates (0, 60, 120, 180 and 240 kg.ha-1) were the sub subplots. The results revealed that NK7328 had a greater leaf area index (LAI) than LVN10 (4.32 versus 3.92 and 4.31 versus 4.11) at both Ba Ria and Dong Nai, respectively. NK7328 also had a greater grain yield than LVN10 at both locations (8.11 versus 7.15 and 8.04 versus 6.72 t.ha-1, respectively). This greater grain yield in these experiments was attributed to a greater number of kernels per ear (KNo) and a greater 1,000-kernel weight (KWt). NK7328 exhibited higher nitrogen use efficiency (NUE) than LVN10 (27.0 versus 21.4 and 29.3 versus 16.4, respectively). Increased PD from 57,000 to 84,000 plants.ha-1 and increased N application rate from 0 to 180 kg.ha-1 increased the anthesis-silking interval and LAI. The grain yield, KNo and KWt decreased with the increased PD and decreased N fertilizer rate. The NUE of the maize hybrid was significantly affected by the N fertilizer rate but there was no effect from PD. The NUE was not associated with the maize grain yield. The optimum PD and N rate were 71,000 plants.ha-1 and 120 kg.ha-1 to be applied for maize under rainfed conditions in southern Vietnam. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Responses of Specific Leaf Weight, Biomass and Seed Yield of Soybean to Nitrogen Starter Rate and Plant Density) ผู้เขียน:Myint Myint Maw, ดร.สุตเขตต์ นาคะเสถียร, รองศาสตราจารย์, ดร.เอ็จ สโรบล, ศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe combined effects of fertilizer and plant population density (PPD) on specific leaf weight (SLW), plant biomass, grain yield and quality of soybean (Glycine max (L.) Merrill) and relationships between these traits are of considerable interest. The purpose of this study was to investigate the response of SLW, biomass distribution in plant parts and seed yield of soybean to nitrogen (N) application and PPD levels. Field experiments were established during the wet season (June to October) and the dry season (November to March) in 2008-2009, using a split-plot design with three replications. The SJ5 cultivar was planted at the National Corn and Sorghum Research Center, Nakhon Ratchasima, Thailand. Four levels of PPD (20, 30, 40, 60 plants m-2) were used as main plots and four rates of N fertilizer (0, 25, 50, 75 kg ha-1) were applied as sub-plots. There were no interactions between PPD levels and N rates in all observations. In both seasons, the greatest SLW was measured at the highest N level (N75) and the lowest value was detected at the highest PPD (60 plants m-2). The SLW at V5 was positively correlated with dry weight (DW) at V5 (r = 0.593*) in the wet season, and with DW at V5 (r = 0.727**) and DW at R5 (r = 0.695**) in the dry season. Accordingly, the highest biomass yield with N75 might be related with SLW at V5. Compared to the control, N75 increased the whole plant biomass at R5 by 14 and 53% in the wet and dry seasons, respectively. The greatest seed yield in both seasons was observed at N75. Pods plant-1 and seed size were the main yield components responsible for a higher seed yield of N75. Significant differences in seed yield among PPD levels were not observed, indicating that a plant density of 20 plant m-2 with N75 would be appropriate for soybean cv. SJ5 sown at the National Corn and Sorghum Research Center in both the wet and dry seasons. |
 ที่มา:สถาบันวิจัยและพัฒนา วิทยาเขตเฉลิมพระเกียรติ จ.สกลนครหัวเรื่อง:อิทธิพลของความหนาแน่นต้นพืชที่มีต่อผลผลิตและองค์ประกอบทางเคมีของข้าวฟ่างอาหารสัตว์ หัวหน้าโครงการ:นายธีระยุทธ จันทะนาม, ผู้ช่วยศาสตราจารย์ |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Water Hyacinth on Open-Channel Water Flow Behavior: Laboratory Scale) ผู้เขียน:Apichote Urantinon, ดร.สิตางศุ์ พิลัยหล้า, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractWater hyacinth (Eichhornia crassipes) is one of the fastest growing plants. Due to its ability to adapt and reproduce, it causes various problems in waterways. The effect of water hyacinth was investigated on flow behavior in an open channel in a laboratory flume. Five different root depths of water hyacinth from natural streams were modeled using a plant floating plate. Four different water hyacinth densities were used. Controls without water hyacinth were also established. The vertical velocity profiles of the cases with and without water hyacinth were compared and the results showed that without water hyacinth, the velocity profile was similar to the theoretical logarithmic distribution in an open channel. In the cases with water hyacinth, the vertical velocity profiles were similar to the theoretical velocity distribution in a closed conduit, in which the velocity in the root zone was zero since water hyacinth floating on the water surface behaved like a solid wall. The experimental data showed that the plant caused flow resistance which tended to slow down the flow. Furthermore, the denser and longer root depth of water hyacinth caused greater flow resistance, as the flow-retarded region extended deeper, occupying about 65.0% of flow depth measured from the water surface. In addition, an empirical formula for flow in an open channel with consideration of water hyacinth effects was developed and a flow velocity empirical formula was obtained which was in good agreement with the observed data used in the verification process. |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Enhancing Sustainable Cassava Production in Hilly Areas of Van Yen, Yen Bai Province, Vietnam) ผู้เขียน:Nguyen Thanh Trung, ดร.สุตเขตต์ นาคะเสถียร, รองศาสตราจารย์, ดร.วิจารณ์ วิชชุกิจ, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractLow awareness on sustainable production and farming techniques are major factors limiting cassava (Manihot esculenta Crantz) production in the northern mountainous region of Vietnam. In 2011, three experiments were conducted in Van Yen District of Yen Bai province, Vietnam, to determine the appropriate plant density (a control at 10,000 plants.ha-1, high stocking at 12,500 plants.ha-1 and extra-high stocking at 14,000 plants.ha-1), the proper NPK+S fertilizer level (low at 800 kg.ha-1, a control at 1,000 kg.ha-1, a high level at 1,200 kg.ha-1 and an extra-high level at 1,400 kg.ha-1), as well as incorporating the study of a suitable cassava intercropping system for controlling soil erosion. The high density and high fertilizer levels signifi cantly increased the fresh root yield, harvest index, root dry matter and starch content compared to those of the control. However, these parameters were not different at both the extra-high density and extra-high fertilizer levels from those of the high density and high fertilizer levels. In addition, there were no signifi cant differences in the sprouting percentage, the stem diameter with increased stocking and the fertilizer level. It was found that cassava intercropped with peanut, using Tephrosia candida hedgerows, not only considerably increased the plant height, fresh root yield, harvest index, root dry matter and starch content, but also effectively decreased the dry soil loss compared to mono-cropping. |
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