University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Geostatistical Analysis of Soil Properties to Support Spatial Sampling in a Paddy Growing Alfisol

Abstract: The information on the spatial and temporal variability of soil properties is vital to improve soil management and to increase the crop productivity. This study was conducted to explore the spatial variability of agronomically important soil properties of a paddy growing tract in Pulasthigama in Polonnaruwa district of Sri Lanka. The study area consisted of 18 ha and a total of 43 soil samples were collected within the plough depth (0- 20 cm). The variability of soil clay content, organic matter, available P, pH, electrical conductivity (EC), exchangeable calcium and available zinc were investigated by means of classical and geostatistical analysis techniques. The coefficient of variation of properties ranged from 5% (pH) to 140% (Zn content). According to the calculated variograms, the available P, clay content and organic matter exhibited a highly spatially structured variability whereas a medium structured variability was observed for soil pH. Pure nugget effects were observed for both available Zn and exchangeable Ca contents indicating a dominance of a random variation. The observed spatial dependencies of soil properties can be used to support spatial sampling for detailed soil mapping and thereby it is suggested that management practices such as fertilizer application, irrigation and tillage operations can be fine tuned at a within fields scale to maximize rice crop production while minimizing the detrimental effects on environment. Key words: Rice; Semi-variogram; Site-specific soil management; Spatial variability. DOI: 10.4038/tar.v22i1.2668 Tropical Agricultural Research Vol. 22 (1): 34-44 (2010)

Recommendations for the Prevention of Coronary Artery Disease in Asians: A Scientific Statement of the International College of Nutrition:

Abstract: There has been a rapid increase in coronary artery disease (CAD) in most Asian countries in association with rapid economic development; however, there is no consensus of opinion on diet and lifestyle guidelines and desirable levels of risk factors for prevention of CAD in these countries. The proportion of deaths due to cardiovascular diseases in Asians may be about 15% but there are wide variations. In view of the lower fat intake of the low-risk rural populations of India, the People's Republic of China, Indonesia, Korea, Thailand and Japan compared with that of urban subjects, the limit for total energy from fat intake in an average should be 21% (7% each from saturated, polyunsaturated and mono-unsaturated fatty acids). The n-6: n-3 fatty acids ration should be 65% and mainly from complex carbohydrates (> 55%). A body mass index of 21 kg/m2 may be safe but the range may be 18.5-23.0 kg/m2 and someone with a body mass index > 23 kg/m2 should be considered overweight. A waist: waist:hip ratio > 0.88 for men and > 0.85 for women should be considered to define central obesity. The desirable limit for serum total cholesterol may be 170 mg/dl, the borderline high level may be 170-199 mg/dl and the high level 200 mg/dl or above. The corresponding values for low-density lipoprotein cholesterol may be 90, 90-109 and 110 mg/dl or above. Fasting serum triglycerides may be 35 mg/dl, which are close to the levels in low-risk rural populations. Fasting blood glucose > 140 mg/dl and postprandial blood glucose > 200 mg/dl may be considered conditions for diabetes, and 140-200 mg/dl, glucose intolerance. An intake of 400 g/day fruit, vegetables and legumes, mustard or soybean oil (25 g/day) instead of hydrogenated fat, coconut oil or butter in conjunction with moderate physical activity (1255 kJ/day), cessation of tobacco consumption and moderation of alcohol intake may be an effective package of remedies for prevention of CAD in Asians.