ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Effect of Nitrogen Levels on Growth, Yield and Fruit Weight to Plant Weight Ratio of Pineapple)

ผู้เขียน:ดร.ณรงค์ จึงสมานญาติ, รองศาสตราจารย์, ดร.สุรัตน์วดี จิวะจินดา, นายวีระพล จันทร์สวรรค์, รองศาสตราจารย์, Udom Kaewsuwan, Panas Buranasilpin

สื่อสิ่งพิมพ์:pdf

Abstract

An experiment was conducted to determine the effect of N on growth, yield, and fruit weight to plant weight ratio (F:P ratio) of pineapple cv. Smooth Cayenne grown in the Eastern part of Thailand. Growth and yield of pineapple increased with increasing N level. The optimum rate of N was in the range of 72 to 96 kg N/rai (1kg/rai = 0.16 kg/ha) wich gave the yield from 13.5 to 14.4 ton/rai. Optimum level of leaf N at forcing time was in the range of 1.4 to 1.8%. Increasing N level decreased or tended to decrease level of leaf P,K,Ca, and Mg. There was no significant effect of N on F:P ratio of the pineapple.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 022, Issue 3, Jul 88 - Sep 88, Page 177 - 184 |  PDF |  Page

ที่มา:วิทยาสารเกษตรศาสตร์ สาขา วิทยาศาสตร์

หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Growth and Physiological Responses to Supra-Optimal Nitrogen and Pre-Anthesis Drought Stress in Maize)

ผู้เขียน:Md. Samim Hossain Molla, ดร.สุตเขตต์ นาคะเสถียร, รองศาสตราจารย์, ดร.เอ็จ สโรบล, ศาสตราจารย์, ดร.วิจารณ์ วิชชุกิจ, รองศาสตราจารย์

สื่อสิ่งพิมพ์:pdf

Abstract

Water and nitrogen (N) are major limiting factors in the production of maize (Zea mays L.) in the tropics and subtropics. A field experiment was conducted during the dry season in 2010–11 at the National Corn and Sorghum Research Center, Thailand to determine the sole and interactive effects of N, water and variety on the growth, physiology and grain yield of maize. Two water regimes (wellwatered and water-stressed) formed the main plots and two hybrids (Pioneer 30B80 and Suwan 4452) and three N levels (0 kg.ha-1, 160 kg.ha-1 (optimal) and 320 kg.ha-1 (supra-optimal) were subplots with three replications using a split plot design and a factorial randomized complete block arrangement. Zero and supra-optimal N, and water-stress significantly reduced the green leaf area (37.86, 6.76 and 17.64%, respectively, at silking), root dry matter (RDM) (62.48, 15.66 and 48.83%, respectively), grain number (20.43, 11.96 and 16.76%, respectively) and grain yield (GY) (31.64, 14.07 and 19.20%, respectively) but not leaf rolling when compared to the control. The leaf relative water content (RWC) decreased (12.87%) significantly only with water-stress. The two hybrids responded differently to N with regard to leaf area—Suwan 4452 was more sensitive to zero N and Pioneer 30B80 was more sensitive to supraoptimal N. Suwan 4452 was lower in RDM (53.92%), grain number (12.90%), and GY (9.66%) than Pioneer 30B80, with the latter performing better under single or combined stress. Higher RDM levels in the surface soil during vegetative growth, the amount of kept green leaves and more grain and a higher RWC were exhibited as drought and N stress tolerance indicators.

Article Info

Agriculture and Natural Resources -- formerly Kasetsart Journal (Natural Science), Volume 048, Issue 5, Sep 14 - Oct 14, Page 676 - 688 |  PDF |  Page