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Paddy and Water Environment

Publisher Springer Berlin / Heidelberg
ISSN 1611-2490 (Print) 1611-2504 (Online)
Subject Collection Biomedical and Life Sciences
Subject Earth and Environmental Science, Life Sciences, Agriculture, Hydrogeology, Geoecology/Natural Processes, Monitoring/Environmental Analysis/Environmental Ecotoxicology, Soil Science & Conservation and Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution
SpringerLink Date Sunday, July 13, 2003

Abstracts of Recent Papers

  • Modeling risk analysis for rice production due to agro-climate change and uncertainty in irrigation water -

    Abstract

    This study proposes a risk analysis model for quantifying the insufficient risk of rice production due to the climate change and variation in irrigation water and cultivation area (named RA_RICE_UCW). In this study, the focus is on uncertainty in agro-climate factors (i.e., total precipitation, average temperature, total sunshine and average radiation) which account for the climate change, the irrigation water from the gauges, surface water and groundwater, respectively. The study data in the research area (Changhua County in Central Taiwan) for the model development and applicability contain 18 years of annual rice productions, agro-climate factors, irrigation water and the cultivation areas. Through the proposed RA_RICE_UCW model, it can be known that large variations in precipitation result in the insufficient risk of rice production (i.e., the probability of demand exceeding supply) and to a more significantly degree than the other agro-climatic factors. Although the temperature is supposed to affect rice production, its variation slightly impacts the insufficient risk of rice production in the case of the annual average temperature being helpful for rice growth. In addition, irrigation water stably supplemented from gauges can enhance the reliability of rice production. However, variation in irrigation water from surface water and groundwater more obviously gets rise to the insufficient risk of rice production than gauged water. Also, groundwater can effectively enhance the reliability of rice production, especially as the lack of irrigation water is supplemented from the gauged and surface water.

  • Woody habitats promote pollinators and complexity of plant–pollinator interactions in homegardens located in rice terraces of the Philippine Cordilleras -

    Abstract

    Bees are important pollinators of wild plants and crops, but little is known about bee habitat requirements and pollinator management in tropical mountainous agricultural regions. Here, smallholder farmers produce fruits and vegetables in homegardens that depend upon or benefit from bee pollination. We hypothesized that abundance and richness of wild and domesticated bees and the complexity of plant–pollinator interactions are higher in homegardens surrounded by woody habitats than in homegardens found farther from woodlands. Bees were sampled in 20 homegardens in the rice terraces of the Philippine Cordilleras. We used linear mixed effect models to analyse effects of woody habitats around homegardens on bee richness and abundance. Based on pooled observations for each garden category, we built pollinator–plant interactions networks to illustrate shifts in interaction frequencies. We recorded 354 bee individuals of 13 wild and one domesticated bee species (Apis cerana). Wild bee richness was significantly higher in homegardens surrounded by woody habitats. Bee abundance increased significantly with increasing flower cover. Wild bees visited cultivated plants significantly more often than domesticated bees. Six vegetable species and 76% of all flower visits on cultivated plants in total were performed by wild bees and three plant species and 24% by domesticated bees. Pollinator–plant networks were more complex in homegardens surrounded by woody habitats. We conclude that woody habitats increase abundance and richness of wild and domesticated bees. Increasing availability of floral resources also promotes bee abundance. In order to promote pollination services in the landscape mosaic of smallholder rice farms, woody habitats and forest fragments together with numerous floral resources should be protected and restored.

  • Modified system of rice intensification for higher crop and water productivity in Meghalaya, India: opportunities for improving livelihoods for resource-poor farmers -

    Abstract

    The productivity and water-use efficiency of traditional rice (Oryza sativa)-based cropping systems in northeastern hill region of India is low and needs to be revisited for improving food security and mitigating the impact of climate change. The adoption of modern agricultural technologies is a necessity for upliftment of agricultural productivity and livelihood of the farming households. Therefore, a modified system of rice intensification (MSRI) was demonstrated in participatory mode during 2010–2012 in 16 farmers’ field of Meghalaya, India, to increase cropping intensity, yield, water productivity (WP) and improve livelihood. The 20-day-old seedlings of improved rice variety ‘Shahsarang-1’ were transplanted at 20 cm × 20 cm spacing with two seedlings hill−1 under MSRI as against 30-days-old seedlings transplanted randomly using 4–5 seedlings hill−1 under farmers’ practice (FP). The average rice productivity under MSRI was enhanced by 39% than that under FP. The employment and net returns were enhanced by 15 and 61% over FP, respectively. Adoption of MSRI also increased water-use efficiency by 12% and WP by 59% compared to FP. The rice crop under MSRI matured 15 days earlier than that under FP. Thus, adoption of MSRI facilitated growing of vegetable pea (Pisum sativum) with average productivity of 4.2 t ha−1 after rice which doubled the cropping intensity and increased farmers’ income. In addition, the available nitrogen, phosphorous, potassium and organic carbon content of soils under rice (MSRI)-pea cropping system were also increased by 7.5, 5.2, 3.4 and 4.3% over antecedent level after 2 years. Hence, MSRI is recommended for enhancing rice productivity, sustaining soil fertility and income of hill farmers in studied ecosystem.

  • Tracing the fate of nitrogen with 15 N isotope considering suitable fertilizer rate related to yield and environment impacts in paddy field -

    Abstract

    While the application rate of nitrogen fertilizer is believed to dramatically influence rice fields and improve the soil conditions in paddy fields, fertilization with low use efficiency and nitrogen loss may cause environmental pollution. In this paper, 15N-labeled urea was used to trace the fate of nitrogen at four rates (0, 75, 225 and 375 kg N/ha) of urea fertilizer over three split applications in Hangzhou, Zhejiang, in 2014. Plant biomass, the soil nitrogen content of different layers, NH3 volatilization and N2O emissions were determined using the 15N abundance to calculate the portion from nitrogen fertilizer. The results indicated that rice yields increased with the application rate of nitrogen fertilizer. NH3 volatilization is the main nitrogen loss pathway, and N2O emissions were significantly associated with nitrogen application rates in the paddy. The percent of nitrogen loss by NH3 volatilization and N2O emissions increased with the nitrogen application rate. This study showed that the suitable N fertilizer in a loam clay paddy, considering the yield requirements and environmental issues, is approximately 225 kg N/ha in Hangzhou, with a distribution of 50.06% of the residual in the rice and soil and 48.77% loss as NH3 volatilization and N2O emissions. The nitrate from fertilization mainly remained in the 0–20 cm level of the topsoil.

  • Effects of Si fertilization on Si in soil solution, Si uptake by rice, and resistance of rice to biotic stresses in Southern Vietnam -

    Abstract

    Silicon (Si) mitigates abiotic and biotic stresses for rice plants (Oryza sativa L.). Here, we test relationships between Si cycling, plant growth, and pest and fungal attacks in rice agroecosystems. We conducted a plot experiment on Si fertilization in a Southern Vietnamese paddy, where plant-available Si was inherently low. For two cropping seasons, we investigated the temporal dynamics of Si in soil solution, plant Si uptake, and the occurrence of leaf folders (Cnaphalocrocis medinalis) and rice blast caused by the fungus Magnaporthe oryzae. Silicon application increased Si concentrations in soil solutions collected in the field as expected from previous laboratory experiments. Soil solution Si concentrations were furthermore affected by Si uptake by plants and by recycling Si with rice straw ash. Silicon concentrations in rice leaves at tillering stage increased with increasing Si application. However, surprisingly, no relationship between Si in soil solution and Si concentration in straw at maturity stage was found. The occurrences of leaf folders and rice blast disease were mitigated by increased Si uptake. However, rice biomass production was not affected, probably because the biotic stress level was generally low. Our field data emphasize the importance of recycling crop residues in rice fields for the Si supply to plants, especially in regions with low Si availability. They furthermore show that under field conditions, the relationship between dissolved Si in soil solution and Si uptake by rice plants is not as straightforward as expected and thus needs to be further investigated.

  • Comparative energy and economic analyses of conventional and System of Rice Intensification (SRI) methods of rice production in Thai Nguyen Province, Vietnam -

    Abstract

    The consumption of energy inputs in agricultural production has been increasing rapidly during the past decades. However, given the limitations and costs of non-renewable energy, increasing production while using the least energy possible has become a major concern of most nations. Prompted by this concern, we conducted a face-to-face survey of 90 farming households in Thai Nguyen Province, Vietnam, to find out how energy is being used in agriculture and, specifically, in their rice production. Through analysis of energy input–output balances, combined with economic efficiency analysis, a comparison was made of conventional and SRI methods of rice production. The study found that applying the SRI method can save around 23% of energy inputs, while increasing energy outputs by 11%. Economic benefits per hectare also rise by more than 8 million dong (USD 364) compared to those under the conventional cultivation system. The study also showed conflicts between the energy and economic balances for manual compared with machine ploughing operations. This study contributes to providing an overview of energy consumption in rice cultivation at the household level. Its findings can help stakeholders to assess current policies and make better decisions on the uses of energy in agricultural production. In addition, the comprehensive approach taken here to analysing energy use and efficiency could expand the analysis and comparison of energy uses at sectoral or activity level—still a new field in Vietnam and many other countries.

  • Effect of swine liquid manure application in paddy field on water quality, soil fertility and crop yields -

    Abstract

    Land application of animal manure has been accepted as an effective method and disposal option, which has economic, environmental and social benefits, while also sometimes exists questions about its impact on soil and water quality and crop yields. This paper presents a field-scale study in Chongming Island, Shanghai, China, where land application of digested swine liquid manure with chemical fertilizer supplement in paddy field (SMC field) was conducted to study the short-term effect on soil quality in different depth, pollutant losses by surface runoff, pollutant concentrations in groundwater and crop yields, compared to conventional paddy field with land application of pure chemical fertilizer (CKC field). The results indicated that: (1) in groundwater, the concentrations of chemical oxygen demand (COD), nitrate nitrogen (Nitrate-N), total phosphorus (TP) and dissolved phosphorus (DP) were significantly increased by 24.69, 17.04, 11.76 and 21.05%, respectively, in the SMC field; (2) in surface runoff, the loss loading of COD, TP and DP was significantly increased by 32.18, 15.46 and 28.13%, respectively, while the ammonia nitrogen (Ammonia-N) was significantly decreased by 31.81%, in the SMC field; (3) in the different depth of soil, the contents of total nitrogen presented a greater decrease in the SMC field, while the contents of TP presented a greater decrease in the CKC field, compared to the properties of original soil; (4) for the crop yields, there was no significant difference between the SMC and CKC field. These practices had proved the feasibility for land application of swine liquid manure in the paddy field, and this approach could be extended after being rate modified to concern the nutrient utilization and pollution risk to water environment.

  • Development of control release urea fertilizer model for water and nitrogen movement in flooded rice -

    Abstract

    Application of control release fertilizer in rice cultivation is a smart way to reduce the environmental nitrogen contamination and enhance the nitrogen use efficiency. The effect of coating thickness and radius of urea granule on nitrogen release rate was modelled, but their effect on nitrogen transformation in soil was not modelled for any crop. In this study, a simple rice water and nitrogen balance model was integrated with a nitrogen release rate model and the effect of coated urea on nitrogen transformations was studied in the CRF-applied flooded rice. The simulated nitrogen release during urea hydrolysis was verified with literature data for uncoated, polymer-coated and mix urea (polymer-coated + uncoated) cases. The integrated model successfully predicted the lag, linear and decay periods of nitrogen release, and peak nitrogen concentration during urea hydrolysis and declining trend during nitrogen transformations. The integrated model could be used as a management tool for determining optimum coating thickness and urea radius for which the nitrogen loss to environment is minimum.

  • Traditional ‘maavee’ rice production in Sri Lanka: environmental, economic and social pressures revealed through stakeholder interviews -

    Abstract

    The Nilwala Ganga Basin of Sri Lanka includes important natural wetlands that are habitat for vulnerable animal and plant species. Flood protection and intensive rice production in the Basin have resulted in degraded acid soils and declining rice yields. However, traditional ‘maavee’ rice production outside the flood protection scheme has continued to generate a high-value rice product. This study reports on interviews conducted with farmers and other stakeholders to document the production practices and the potential environmental and economic benefits associated with maavee rice paddies. The maavee production system has prevailed for at least several decades. Farmers apply no chemicals to their paddies, relying instead on alluvial deposits as a source of nutrients, and on the natural pest and disease resistance of their traditional varieties. The maavee rice product can attain three times the selling price of rice from conventional farms making it more economically viable than conventional rice production. However, much of maavee production is for home consumption and the system is threatened by increasing labour costs, an ageing farming population and pressures to increase rice yields. Non-invasive production practices and the proximity of maavee paddies to regenerating wetlands in the Kirala Kele Sanctuary suggest that traditional paddies may constitute an important habitat for vulnerable wildlife; however, maavee farmers also perceive wetland birds as potentially damaging to rice. Based on a SWOT (strengths, weaknesses, opportunities and threats) analysis, we make recommendations for future research needs and potential management actions to safeguard the environmental and economic sustainability of the maavee system.

  • Erratum to: International academy of agricultural and biosystems engineering (iAABE): a new instrument for recognizing the top profession