Assay of urease activity in soils

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Yahya Mohd Nor

Abstract

A method for assay of urease activity is described. It involved aerobic incubation of a 10-g sample of soil at 37oC for 6 hours after addition of urea substrate to it, and colorimetric determination of the urea remaining after extraction with 2.5M KCI containing Ag2 SO4 (100 ug/ml) as urease inhibitor. The effect of extractant on the colour of the complex and recoveries of urea added to soils by the method were also evaluated. The urease activity in 14 Malaysian soils studied indicated that the soils have varying capacity to hydrolyzed urea. Soil pH and urease activity correlated well, but neither organic carbon content nor cation exchange capacity bore any significant relationship.

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The digestibility of chemical treated bagasse in molasses-based diets for sheep and goats

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C. Devendra

Abstract

A study is reported on the digestibility by sheep of molasses -based diets containing 5,10, 15,20,25,30,35 and 40 per cent bagasse treated with 4 and 6 per cent NaOH. Treatment with NaOH reduced the crude fibre content of crude bagasse by 22 to 28 per cent. The data on intake and apparent digestibility of nutrients indicated a decreasing trend with increasing level of dietary bagasse. With both levels of NaOH usage, statistically significant differences between treatments were only found in dry matter, organic matter, crude fibre and energy digestibility. The general pattern of the results favoured the 4 per cent level of NaOH, and indicated that the optimum level of bagasse inclusion was 20 to 30 per cent in the diet. A lower level of alkali used will also tend to reduce the cost of treatment. The possible reasons for the improved digestibility are discussed. Comparative intake and digestibility data between sheep and goats for both levels of NaOH, but specific to 20 and 40 per cent bagasse levels in the diet, indicated that goats had a superior digestive efficiency. Statistically, significant higher digestibility data for crude fibre and energy were recorded (P<0.05) goats compared to sheep for the 40 per cent bagasse level. The need for further work in this direction, especially with regard to processing and possibly also heat treatment so as to promote improvements in feeding systems involving the by-products is stressed.

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Effect of sheath blight disease on the yields of three rice varieties

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B.L Ho

Abstract

Sheath blight disease of rice could cause a very significant yield loss of 30% for a susceptible variety IR 1487. For a resistant variety (lR 20) and an intermediate variety (Mahsuri ), the yield losses of 1 - 4%  were not significant.

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The use of rubber seed meal in poultry 1. The effect of varying levels of rubber seed meal in broiler diets

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S.W Yeong and Syed Ali, A.B

Abstract

Two experiments were carried out to study the use of rubber seed meal (RSM) in broiler chickens growth from 5th to 10th week of age. In the first trial the body weight gain and feed efficiency of chicks were adversely affected (P<0.05) when RSM level was higher than 30% in the diet replacing maize and soybean meal. Supplementation of extra 0.15% DL-methionine to the high RSM-based diets did not reverse the adverse effect of RSM. In the second trial, RSM was added to 45% in the diet with proper balance of dietary lysine and methionine levels. It was observed that the feed intake, body weight gain and feed efficiency of birds fed methionine and lysine supplemented RSM-based diets were not significantly different from those fed the control. The metabolizable energy value in rubber seed meal was 2,861 + 159 kcal/kg on a dry matter basis. RSM could be supplemented to as high as 45% to broiler diets provided that the levels of lysine and methionine were adjusted to meet their requirement.

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Maturation of Malaysian fruits. iv. storage conditions and ripening of passion fruit (Passiflora Edulis L. Var. Flavicarpa

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W.J Broughton and B.E Chan

Abstract

Physiological changes were measured during the ripening and storage of a Malaysian variety of passion fruit. The fruits were subjected to different temperatures and storage atmospheres, and their rate of ethylene and carbon dioxide evolution measured.Passion fruits ripened normally between 20oC-30oC. Removal of carbon dioxide accelerated ripening,while low or high himidities were detrimental to the fruit. Recommended storage conditions are; temperatures about 20oC at 85%-90% relative himidity.

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