Effect of rice cultivar on greenhouse-gas emissions from rice-fish co-culture

In aquaculture,co-culturing rice with fish may mitigate greenhouse-gas emissions.In this study,co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH_(4)and N_(2)O emissions relative to fish monoculture.Differences in CH_(4)and N_(2)O emissions among rice cultivars primarily stem from the differential effects of rice plants on plant-mediated CH_(4)transport,CH_(4)oxidation and nitrogen absorption.

Conservation of Traditional Rice Varieties in a Globally Important Agricultural Heritage System (GIAHS):Rice-Fish Co-Culture

The traditional rice-fish farming system is selected as a ＂globally important agricultural heritage system＂ （GIAHS） by the Food and Agriculture Organization （FAO）,United Nations Development Programme （UNDP）,and Global Environment Facility （GEF）,etc.In Zhejiang Province of China,where the pilot site for this GIAHS farming system is located,we compared the use of traditional rice varieties in rice-fish co-culture and rice monoculture.Further,we determined how traditional rice varieties were performed in this rice-fish system.Only 19% of the farmers who practiced rice monoculture planted traditional varieties while 52% of farmers who practiced rice-fish co-culture planted traditional varieties.Traditional varieties represented 13% of the total land cultivated under rice in the rice-fish system but only 2% in the rice monoculture system.In the rice-fish system,yield was lower for traditional rice varieties than hybrid varieties but application of fertilizers and pesticides was also lower.In a field experiment in the rice-fish system without pesticides,rice planthopper numbers and sheath blight incidence were lower from three traditional varieties than one hybrid variety;yields were 8 to 32% lower from the traditional varieties than the hybrid.Our results showed that traditional rice varieties can be preserved through conserving GIAHS rice-fish co-culture.Our study also indicated that traditional rice varieties can survive in the rice-fish system because these varieties are helpful to the whole system and beneficial to the farmers.

Characteristics of Growth and Yield Formation of Rice in Rice-Fish Farming System

By using single rice cultivation as a control, the effect of rice-fish culture on growth dynamic, plant type and yield formation of rice was studied. The results showed as follows： rice-fish culture improved the physical-chemical properties of arable layer soil of paddy field, extended growth period of rice, increased dry matter and LAI of different growth stages, improved three top leaves area, deterred the degeneration of leaves function, increased the diameter of stem, promoted the growth of roots and the formation of roots in the extended stem. At the same time, rice-fish culture extended the length of basal internodes, increased the number of internodes, uplifted the gravity of plant, and depressed the root vigor. For the grain yield and yield structure office, rice-fish culture decreased ear/tillering ratio, spikelet/panicle and seed set percentage, increased grain weight. If variety choice and cultivation technology were controlled appropriately, rice-fish culture could increase the effective panicles and improve grain yield of rice.

Effects of Rice-Fish Co-culture on Oxygen Consumption in Intensive Aquaculture Pond

Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.

Methane and Nitrous Oxide Emissions from Rice-Duck and Rice-Fish Complex Ecosystems and the Evaluation of Their Economic Significance

Rice-duck （RD） and rice-fish （RF） ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane （CH4） and nitrous oxide （N2O） emissions and their economic value from these two ecosystems can provide theoretical and practical basis for further development and utilization of these classical agricultural techniques. CH4 and N2O emissions from RD and RF ecological systems were measured in situ by using static chambers technique. Using global warming potentials （GWPs）, we assessed the greenhouse effect of CH4 and N2O and their economic value. Results showed that the peaks of CH4 emission fluxes from RD and RF appeared at full tillering stage and at heading stage, and the average emission fluxes were significantly （P〈 0.05） lower than that from CK. N2O fluxes remained low when the field is flooded and high after draining the water. Compared with CK, the total amount of N2O emissions was significantly （P〈0.05） higher and slightly lower than those from RD and RF, respectively. In 2006 and 2007, the total greenhouse effect of CH4 and N20 from RD and RF were 4 728.3 and 4 611 kg CO2 ha^-1, 4 545 and 4 754.3 kg CO2 ha^-1, respectively. The costs of greenhouse effect were 970.89 and 946.81 RMB yuan ha^-1, and 933.25 and 976.23 RMB yuan ha^-1, respectively, which were significant lower than those from CK （5 997.6 and 5 391.5 RMB yuan ha^-1）. Except for the environment cost of CH4 and N2O, the economic benefits from RD and RF were 2 210.64 and 4 881.92 RMB yuan ha^-1; 3 798.37 and 5 310.64 RMB yuan ha^-1, respectively, higher than those from CK. Therefore, RD and RF complex ecological planting and breeding models can effectively decrease and control CH4 and N2O emissions, and they are two of the effective strategies to reduce greenhouse gases from rice paddy fields and contribute in alleviating global warming. Thus, their adoption is important to the environment together with their economy benefits.

Logistic Regression Analysis on Factors Affecting Adoption of Rice-Fish Farming in North Iran

We evaluated the factors influencing the adoption of rice-fish farming in the Tavalesh region near the Caspian Sea in northern Iran. We conducted a survey with open-ended questions. Data were collected from 184 respondents （61 adopters and 123 non-adopters） randomly sampled from selected villages and analyzed using logistic regression and multi- response analysis. Family size, number of contacts with an extension agent, participation in extension-education activities, membership in social institutions and the presence of farm workers were the most important socio-economic factors for the adoption of rice-fish farming system. In addition, economic problems were the most common issue reported by adopters. Other issues such as lack of access to appropriate fish food, losses of fish, lack of access to high quality fish fingerlings and dehydration and poor water quality were also important to a number of farmers.

Ecological footprint analysis on the traditional rice-fish agricultural area:a case study of Qingtian County,Zhejiang Province,China

Qingtian County of Zhejiang Province, China has maintained the traditional rice-fish agriculture for about 2,000 years and formed exceptional cultural heritage based on this kind of production mode, so it was ed by FAO as a pilot site for the rice-fish agricultural heritage systems in 2005. This research has applied the indicators of ecological footprint and biocapacity to monitor the environmental conditions of Qingtian County, aiming to find the impact that the traditional agricultural production mode and the local inhabitants lifestyle have placed on the local environmental conditions as well as the role they have played in maintaining ecological balance, cultural inheritance and regional sustainable development. Results show that Qingtian County is characterized by a nearly breakeven total ecological balance, as opposed to Zhejiang Province, the world and other agricultural regions. However, compared with another rice-fish agricultural region, Congjiang County which enjoys a considerable ecological reserve, Qingtian County has consumed a greater amount of environmental resources. Specifically, about half of the ecological footprint of Qingtian County can be attributed to the cropland （50.8%） while the CO2 area only accounts for 11.2%, which is dramatically different from that of the modern industrialized regions. And a vast of percentage of energy is caused by the combustion of fuelwood which not only requires the land to absorb the CO2 emission it has generated but also occupies the forest where it has been chopped.

Impact of Rice-Catfish/Shrimp Co-culture on Nutrients Fluxes Across Sediment-Water Interface in Intensive Aquaculture Ponds

Exchange of nitrogen and phosphorus across sediment-water interface plays an important role in the management of nutrient recycling in the aquaculture pond. In this study, a plot experiment was conducted to study the effect of rice-catfish/shrimp co-culture on the micro-profile of oxygen (O2), pH and nutrient exchange across sediment-water interface in the intensive culture ponds. The results showed that rice-catfish co-culture increased the concentration and penetrating depth of O2, but decreased the pH value across the sediment-water interface, compared with catfish monoculture. Additional rice cultivation significantly reduced the flux rates of ammonium (NH4+) and nitrate (NO3-) across sediment-water interface in the catfish and shrimp ponds. The flux rates of NO2 - and soluble phosphorus (PO43-) showed no significant difference between rice-catfish/shrimp co-culture ponds and catfish/shrimp monoculture ponds. Rice only affected the dissolved inorganic nitrogen and phosphorus fractions in the sediment. The concentrations of NH4 + were significantly lower in the sediment of co-culture ponds than in the monoculture ponds. Additional rice cultivation also significantly reduced the content and percentage of dissolved inorganic phosphorus in the sediment of catfish ponds.

Residents’ Attitudes Towards Tourism in a Globally Important Agricultural Heritage Systems Pilot Site: a Case Study in China

Globally Important Agricultural Heritage Systems (GIAHS) is a wide program to promote the conservation and adap-tive management of such systems and their associated landscapes, biodiversity, knowledge systems and cultures. Rice-Fish Systems (RFS) in Longxian village of China, as a traditional agricultural system, was selected as one of the five pilot sites of GIAHS in 2005. Researchers have paid more attention to the dynamic conser-vation and adaptive management of RFS because it is under severe threats from global development challenges. Tourism is suggested to be brought into the RFS conservation program as an alternative industry. This paper presents a comparative study of residents in three types of farm household in Longxian, seeking attitudes to the RFS conservation and tourism development and ways in which such information may guide future strategies. Results show resi-dents, belonging to the household type in which most family mem-bers are abroad, have the most positive attitudes to RFS conserva-tion and tourism development; while residents, as other household type in which less than 50% of family members are abroad, are the least sensitive group in these three household types, due to the motivation of moving abroad weakening their enthusiasm to participate in the local activities. Implications are discussed in the context of how resident attitudes will affect the future manage-ment of GIAHS conservation and tourism development, and then measures are put forward to foster tourism cooperation and multi-stakeholders process establishment.

High Yield and Efficient Cultivation Techniques of Rice under Rice- fish Intergrowth Model in Chengdu

The integrated planting and breeding of paddy fields is a kind of eco-planting and breeding mode which makes rice and aquatic animals benefit from each other,greatly reducing the harm of rice pests and diseases,using less or even no fertilizers or pesticides,greatly reducing the agricultural non-point source pollution,thus achieving the " multiple use of water,multiple harvests in one field,grain and fishing winwin,ecological and high efficient use. " In this paper,the high yield and efficient cultivation techniques of rice under the rice-fish intergrowth model in Chengdu was introduced from the aspects of selecting good paddy fields for fishing,using appropriate rice varieties,soaking disinfection,timely sowing and nurturing strong seedlings,reasonable close planting,reasonable fertilization,scientific water management,scientific pest control and rice harvests.

Conceptual Framework for Economic Evaluation of Globally Important Agricultural Heritage Systems (GIAHS): Case of Rice-Fish Co-Culture in China

The Globally Important Agricultural Heritage Systems （GIAHS） initiative was launched by the Food and Agriculture Organization （FAO） of the United Nations in 2002 with the aim of establishing the basis for the global recognition,dynamic conservation and adaptive management of outstanding traditional agricultural systems and their associated landscapes,biodiversity,knowledge systems and cultures.There is anecdotal evidence that designated GIAHS are economically better than non-GIAHS sites.However,there have not been done an economic analysis to prove this.Nor are any sophisticated economic performance criteria for GIAHS in place for a continuously monitoring of the functioning.Therefore,the main objective of this study is to conduct an economic valuation for a GIAHS system versus a similar non designated GIAHS system.For this,a Cost-Benefit Analysis （CBA） is chosen.The major constraint is the data availability.Therefore,a framework for economic analysis shall be developed with the intention to provide directions,assumptions,and data requirement to carry out an economic analysis and so give guidance on future inclusion of economic valuations of GIAHS.Theconceptual framework for economic assessment will use the Rice-Fish pilot site in China as a case study.The example calculations on the rice-fish co-culture （RFC） have to be taken cautiously due to data availability on different activities （tourism,marketed products on local and international markets） as well as comparison to similar systems.

Ecological Benefit Evaluation of Agricultural Heritage System Conservation——A Case Study of the Qingtian Rice-Fish Culture System

In order to better understand the developmental conditions and trends of the biodiversity at agricultural heritage sites,the structure and function of the ecosystem and ecological environment in Qingtian Rice-Fish Culture System is examined in the decade since the implementation of the GIAHS project.Through the collection of historical data and sample-plot survey,this study collates the data from 2005 to 2013 related to the heritage site to evaluate the ecological benefit of the Agricultural Heritage System conservation.The results show that:(1)Since the implementation of heritage conservation,the variety of traditional rice grown at the heritage sites basically remains stable,the varieties of other crops basically remain unchanged and the varieties of fruit trees and medicinal plants have developed at faster rates.As the ecological environment at the heritage sites gradually improved,the species and richness of the biodiversity in the ecosystem have increased,especially the increasing growth of egrets and boars.(2)From 2005 to 2013 in the Fangshan Town of Qingtian County,the ecosystem areas identified as river,forest,urban and bare land have increased.The increased area of the urban ecosystem is the largest one of them,which is up to 20.30 ha;while the area of the forest ecosystem has increased to 7.29 ha.The areas of wetland,reservoir,farmland and grassland have been reduced,and the area of grassland ecosystem has been reduced the most with a reduction of 28.87 ha.From the changes in the values of the ecosystem services of different ecosystem types,the values of forest ecosystem services have achieved the most growth,reaching up to 92000 yuan yr-1 and the growth of the river and bare land ecosystem service values are not obvious.(3)Over nearly a decade,the soil nutrients and the water quality of rice fields at the heritage site have not obviously changed and the plant diseases and insect pests in the rice fields have not been aggravated.The monitoring indexes are far better than the standard values.With the great support of the local government,the production and living conditions and the living environments of farmers in the villages of the heritage sites have been greatly improved through road reconstruction,water improvement,toilet enhancements and the greening,brightness and beautification of the villages.

Design and Application of the Annual Report of Globally Important Agricultural Heritage Systems(GIAHS)Monitoring

Scientific and effective heritage monitoring can not only realize the conservation of the heritage itself and the maintenance of its values,but it can also realize the sustainable development of the heritage site.In order to promote the conservation and management of Globally Important Agricultural Heritage Systems(GIAHS),this study proposed a design for the annual report of GIAHS monitoring under the overall framework of the GIAHS monitoring system,and explored the application of the annual report in the first GIAHS site in China:the Qingtian Rice-Fish Culture System.In the design scheme of this study,the GIAHS annual monitoring report is composed of 24 monitoring items,with each of them logically related.It is to be filled in by the bureaus of the heritage site and reported through the GIAHS dynamic monitoring system.The results of an analysis of the annual reports of Qingtian Rice-Fish Culture System for four years showed that Qingtian County has taken a series of conservation and development measures which have reduced the area of abandoned paddy,enhanced the unit benefit of agri-products,and increased the farmers’income.At the same time,the heritage site is faced with various challenges and threats,such as the weakening of the tourism attraction,the aging of the heritage practitioners,and the limitation of the heritage-themed agri-products and tourism income,which need to be addressed with proper measures.The results can also provide guidance for other GIAHS based on indications that heritage sites should improve the development of cultural products,the construction of social organization and the cultivation of spontaneous publicity,and an exchange and learning mechanism should be established among them in the future.The design and application of the GIAHS annual monitoring reports can not only provide specific guidance for conducting the GIAHS monitoring,but also lay the foundation for evaluating the effectiveness of GIAHS conservation and management.This study is expected to help enrich the theory of GIAHS monitoring,further promote China’s GIAHS monitoring work,and also provide China’s experience for the benefit of international GIAHS monitoring efforts.

Ecosystem service tradeoff between traditional and modern agriculture： a case study in Congjiang County, Guizhou Province, China

Besides crops, agriculture supplies all three major categories of ecosystem services （ES）. However, agriculture also supplies an array of ecosystem dis-services （EDS） that may harm other ecosystems. The flows of ES and EDS are directly dependent on the management of agricultural ecosystems. The traditional method of Chinese agriculture, which supports sustainable agriculture, has been proven to increase ES and reduce EDS. However, there is a lack of a detailed understanding of the ES and EDS associated with traditional agriculture, and also of differences between traditional and modem agriculture. In this study, an investigation was conducted on the ecosystem services （ES） and ecosystem dis-services （EDS） of traditional and modem agriculture in Congjiang County, Guizhou Province, China. Afterwards, the economic values of ES and EDS were quantified experimentally and calculated based on the market price. The results show that： the net economic value of traditional rice-fish agriculture was 3.31 x 104 CNY.haI （6.83 CNY = 1 USD as of July, 2009） and that of rice monoculture was 1.99 x 104 CNY.ha ~. Significant differences existed between traditional rice-fish and rice monoculture fields for their economic values of some ES or EDS. A benefit and cost analysis （BCA） model was used to adjust the conflict between the economic income and environmental loss from traditional and modem agricul- ture. The BCA model not only calculates the net income but also monetizes the EDS of the agricultural systems. The results showed that the net income of rice-fish agriculture was 1.94x 104CNY.ha-1 higher than that of rice monoculture. However, the benefit to cost ratio （BCR） of rice-fish agriculture was lower than that of rice monoculture, indicating that the traditional agricultural model was not the most optimized choice for farmers. The value of the rice-fish agriculture was much higher than that of the rice monoculture. Thus, when considering the benefits that rice-fish agriculture contributes to the large- scale society, these agricultural methods needs to be utilized. Furthermore, the labor opportunity costs were calculated and the comprehensive value of rice mono- culture was negative. Finally, the compensation standard was calculated based on the comprehensive benefit analysis. The lowest level was 1.09×103 CNY.ha-1, and the highest level was 1.21 × 104 CNY.ha-1.