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 ที่มา:PHOTOSYNTHETICAหัวเรื่อง:Effect of leaf age and position on light-saturated CO2 assimilation rate, photosynthetic capacity, and stomatal conductance in rubber trees |
 หัวเรื่อง:อิทธิพลของชนิดและอัตราปุ๋ยไนโตรเจนที่มีต่อผลผลิตของหญ้ากินนีที่ปลูกบนชุดดินกำแพงแสนในสภาพไร่นา ผู้เขียน: Prasert Bunpithukkeit สื่อสิ่งพิมพ์:pdf AbstractA field experiment was established to determine the influence of nitrogen sources and nitrogen rates on the dry matter production of Guinea grass grown on Kamphaeng Saen soil series (Typic Haplustalp five silty, mixed). The experiment was conducted at experimental farm of the Department of Soil Science, (Kamphaeng Saen campus), Kasetsart University, Nakorn Pathom. In 1989, a factorial experiment in randomized complete block design of three nitrogen sources, urea (46% N), ammonium sulfate (21% N) and ammonium chloride (25% N) While rates of nitrogen were 0, 25, 50 and 75 kg N/rai with 3 replications. The grass was harvested for analysis every month and these analysis have carried out for six months. The average of dry matter yields and N yields of Guinea grass showed no significant difference from various nitrogen fertilizers. The ammonium sulfate application gave the highest average dry matter of 2,230 kg/rai. On the other hand, the highest N yields was 33.04 kg/rai when applied ammonium chloride. The yields of Guinea grass increased with increasing level of nitrogen fertilizer application. Average dry matter production of Guinea grass obtained from different rate of nitrogen fertilizer were significant difference and at 75 kg N/rai, the highest dry matter yields and N yields were 2,720 and 45.86 kg N/rai, respectively. The recovery of nitrogen was between 38% to 45%. The highest nitrogen recovery was 45% from ammonium chloride, following by urea 43%, While the lowest one was about 38% from ammonium sulfate. |
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