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a b s t r a c tRecent years have seen a surge of interest in assessing water withdrawal in the agricultural sector which has been experiencing an increasing concern with sustainable environmental requirements. Like other highly water-intensive crops, rice production systems rely on an ample water supply, thus posing a serious threat to water availability. This study estimates the water use of rice cultivated in the off-and main seasons in Malaysia. The water withdrawal of rice was estimated based on the monthly climatic data of 30 y (1983-2013) and a 10-y (2002-2011) average annual crop yield. The water stress index (WSI) of the 16 major watersheds in Malaysia was also derived to assess the water deprivation. We found that the blue water use for rice cultivation in the off-and main seasons ranges between 619 and 1,421 m 3 /t and 504 and 1,031 m 3 /t, respectively. The results also showed that the average WSI for 11 states in Peninsular Malaysia is 0.08 with a total water deprivation of 97 million m 3 H 2 O eq/y. This study can serve as baseline information for the government in identifying the areas that need to be conserved and the recommendations that should be drawn toward sustainable management of water resources in Malaysia.

Agriculture has become a major user of global freshwater resources. This study measured the consumptive water use of 15 selected crops (cash crops, vegetables, and fruits) in Malaysia. The results indicated that the green water consumption footprint (129.8 m 3 /ton -1586.0 m 3 /ton) was higher compared to the blue water consumption footprint (21.0 m 3 /ton -931.0 m 3 /ton) for all 15 crops in Malaysia. Paddy crop had the highest total water consumption footprint for both off and main seasons with 2265 m 3 /ton and 2255 m 3 /ton, respectively, due to the cultivation practices under flood conditions. The water consumption footprint depends on the crop yield, implying that th e higher the crop yield, the lower the value is. This paper provides a comprehensive review of the assessment of the water consumption footprint of crop production in Southeast Asia from 2007 to 2017 (10 years). The paper also highlights and discusses a feasibility study for the water consumption footprint of crops and future outlooks in Southeast Asia following an LCA-based approach.

Water scarcity has emerged as a global issue and the situation is getting worse. In accordance with the urgency, this study aimed to assess the suitability of a rainwater harvesting system (RWHS) to supply water for domestic uses in residential colleges in the Bangi campus of Universiti Kebangsaan Malaysia (UKM). The study also analysed the level of awareness on the importance of rainwater and RWHS among the students residing in the 10 residential colleges. The study used Likert scale 1 -5 questionnaire survey method and the sample involved 1,075 respondents randomly selected from 10 residential colleges in UKM. The findings showed that the suitability of rainwater collected by the RWHS for domestic uses had a mean of 3.45, while the mean value of awareness level towards the importance of rainwater and RWHS was 3.75. The questions group with the lowest mean score was "knowledge regarding the objectives of collection and reuse of rainwater", with a mean of 3.28. A case study of RWHS was carried out by installing a RWHS in one of the residential college, namely Ungku Omar College. Residents at Ungku Omar College got the highest total percentage for "agree" and "strongly agree" scores when being asked if rainwater collected by RWHS is suitable for domestic uses, as compared to the scores obtained by other residential colleges. Among the important aspects of RWHS include safety of water collected, sustainability of the system and quantity of water collected with mean of 4.39, 4.19 and 4.07, respectively. In conclusion, RWHS is a method that can be widely accepted among college students at UKM, mainly for domestic uses. However, further efforts should be incorporated to increase the awareness level and knowledge on the importance of conserving water resource.

Unsustainable rice straw management causes environmental impacts; hence, utilisation of rice straw for bioenergy is a promising strategy for sustainable rice straw management. Although rice straw has a high potential for bioenergy generation, the whole production cycle and application may cause environmental damage that is not fully understood. Hence, environmental performance studies are required to determine the most effective rice straw utilisation options. A comprehensive approach, such as life-cycle assessment (LCA), can give comprehensive information on the possible environmental effects of rice straw utilisation for bioenergy. Therefore, this study briefly overviews the LCA of rice straw utilisation for bioenergy production. It is found that utilisation of rice straw for bioenergy could reduce global warming potential compared to energy production from fossil fuels. However, it is suggested that other impact categories in LCA be evaluated in the bioenergy production from rice straw research to determine the overall sustainability of the production.