31,447 research outputs found

    Confronting the environmental consequences of the Green Revolution in Asia:

    Get PDF
    Intensive double or triple monocropping of rice has caused degradation of the paddy micro environment and reductions in rice yield growth in many irrigated areas in Asia. Problems include increased pest infestation, mining of soil micronutrients, reductions in nutrient-carrying capacity of the soil, build-up of soil toxicity, and salinity and waterlogging. Emerging sustainability problems in intensive rice agriculture show the need for a greater understanding of the physical, biological and ecological consequences of agricultural intensification and greater research attention to long term management of the agricultural resource base.Green Revolution Asia., Rice Yields Asia., Environmental degradation., Sustainability., Resource management., Agricultural resources.,

    Quantifying N response and N use efficiency in Rice-Wheat (RW) cropping systems under different water management

    Get PDF
    About 0·10 of the food supply in China is produced in rice¿wheat (RW) cropping systems. In recent decades, nitrogen (N) input associated with intensification has increased much more rapidly than N use in these systems. The resulting nitrogen surplus increases the risk of environmental pollution as well as production costs. Limited information on N dynamics in RW systems in relation to water management hampers development of management practices leading to more efficient use of nitrogen and water. The present work studied the effects of N and water management on yields of rice and wheat, and nitrogen use efficiencies (NUEs) in RW systems. A RW field experiment with nitrogen rates from 0 to 300 kg N/ha with continuously flooded and intermittently irrigated rice crops was carried out at the Jiangpu experimental station of Nanjing Agricultural University of China from 2002 to 2004 to identify improved nitrogen management practices in terms of land productivity and NUE. Nitrogen uptake by rice and wheat increased with increasing N rates, while agronomic NUE (kg grain/kg N applied) declined at rates exceeding 150 kg N/ha. The highest combined grain yields of rice and wheat were obtained at 150 and 300 kg N/ha per season in rice and wheat, respectively. Carry-over of residual N from rice to the subsequent wheat crop was limited, consistent with low soil nitrate after rice harvest. Total soil N hardly changed during the experiment, while soil nitrate was much lower after wheat than after rice harvest. Water management did not affect yield and N uptake by rice, but apparent N recovery was higher under intermittent irrigation (II). In one season, II management in rice resulted in higher yield and N uptake in the subsequent wheat season. Uptake of indigenous soil N was much higher in rice than in wheat, while in rice it was much higher than values reported in the literature, which may have consequences for nitrogen fertilizer recommendations based on indigenous N suppl

    Rice and Water: The Final Frontier

    Get PDF
    Outlines the threat of diminishing water resources for rice crops, the economic and social dimensions of the droughts' potential effects, and the new cultural systems and adapted rice varieties being pursued as potential solutions

    Environmental justice in agricultural systems. An evaluation of success factors and barriers by the example of the Philippine farmer network MASIPAG

    Get PDF
    A twofold challenge arises from the normative aim of environmental justice to the management of agricultural systems: (1) the improvement of food security and livelihood of the rural poor today; (2) the sustenance and enhancement of the long-term productivity and resilience of agricultural systems to future generations. The paper analyzes the success factors and barriers of the Philippine farmer network MASIPAG in simultaneously realizing both objectives - based philosophically on Rawls’ “A Theory of Justice” (1971), conceptually on specific determinants of the relationship between the objectives, and empirically on the results of a comprehensive evaluation of the MASIPAG network.environmental justice, ecosystem services, agriculture, agrobiodiversity, Philippines

    Integrated Land Use Planning and Sustainable Watershed Management

    Get PDF
    This paper discusses the key issues and concerns regarding sustainable Philippine watershed management. Emphasis is made on the various requisites of a sustainable management with a focus on the critical roles of land use planning.land use planning, land management, watershed

    Water-wise Rice Production

    Get PDF
    Rice is a profligate user of water. It takes 3,000–5,000 liters to produce 1 kilogram of rice, which is about 2 to 3 times more than to produce 1 kilogram of other cereals such as wheat or maize. Until recently, this amount of water has been taken for granted. Now, however, the water crisis threatens the sustainability of the irrigated rice ecosystem. In Asia, 17 million ha of irrigated rice areas may experience ‘physical water scarcity’ and 22 million ha ‘economic water scarcity’ by 2025. To safeguard food security and preserve precious water resources, ways must be explored to grow rice using less water. IRRI, together with Plant Research International of Wageningen University and Research Centre, organized a thematic workshop on Water-Wise Rice Production held 8-11 April 2002 at IRRI, Los Baños, Philippines. The objectives were to present and discuss the state-of-the-art in the development, dissemination, and adoption of water-saving technologies at spatial scales ranging from the field to irrigation system. This book contains the papers presented at the workshop
    corecore