Survey of Rice Cropping Systems in Kampong Chhnang Province,Cambodia

Although Cambodia might have achieved self-sufficiency and an exported surplus in rice production,its rice-based farming systems are widely associated with low productivity,low farmer income and rural poverty.The study is based on a questionnaire village survey in 14 communes containing 97 villages of Kampong Chhnang Province from March to June,2011.It analyzes the prevailing rice-based cropping systems and evaluates options for their improvement.Differences in cropping systems depend on the distance from the Tonle Sap water bodies.At distances greater than 10 km,transplanted wet-season rice cropping system with low productivity of about 1.6 t/hm 2 prevails.This deficiency can be primarily attributed to soils with high coarse sand fractions and low pH (< 4.0),use of ’late’ cultivars,and exclusive use of self-propagated seeds.To improve this cropping system,commercial ’medium’ cultivars help prevent crop failure by shortening the cultivation period by one month and complementation of wet-season rice with non-rice crops should be expanded.Areas adjacent (≤ 1 km) to the water bodies become inundated for up to seven months between July until January of each year.In this area,soils contain more fine sand,silt and clay,and their pH is higher (> 4.0).Farmers predominantly cultivate dry-season recession rice between January and April.Seventy-nine percent of the area is sown directly and harvested by combines.Adoption ratio of commercial rice seeds is 59% and yields average 3.2 t/hm 2.Introduction of the second dry-season rice between April and July may double annual yields in this rice cropping system.Besides upgrading other cultivation technologies,using seeds from commercial sources will improve yield and rice quality.Along with rice,farmers grow non-rice crops at different intensities ranging from single annual crops to intensive sequences at low yields.     

Developing fertilizer recommendations for rice in Sub-Saharan Africa,achievements and opportunities

Improving agricultural productivity to keep pace with the fast-growing food demand is a huge challenge for sub-Saharan Africa (SSA). Fertilizer is a powerful productivity-enhancing input; nevertheless, farmers of SSA use only 5–9 kg ha^?1 of fertilizer, which is ten times lesser than Latin America and Asia (50 and 80 kg ha^?1, respectively). Rice (Oryza sativa) is one of the most important food crops of SSA, and its consumption is growing faster than any other commodity in Africa. Rice-based systems have high potential for improving food production through an efficient management of fertilizers. The biophysical environment, cropping systems and socio-economic status of farmers including market opportunities are the main factors for developing appropriate fertilizer recommendations. Many research efforts have been invested in different countries to develop fertilizer recommendation for rice. However, the diversity of rice ecologies, the type and the cost of fertilizers available on local market are the main constraints for development of blanket recommendations of fertilizer usually applied in many countries. Here, we make a reviews of the progress made on the development of fertilizer recommendations for rice-based systems in SSA. The utilization of the new concepts and decisions support tools for development of fertilizer recommendation and the main achievements and weakness are discussed. The opportunities offered by the new concepts, modeling and decision support tools are discussed in a regional strategic approach for better management of fertilizers in the diversified ecologies of rice-based systems.     

Meeting the challenges of global rice production

Rice is the second most widely grown cereal crop and the staple food for more than half the world's population. More than 3 billion people consume more than 100 kg of rice per year. Rice is cultivated on 155.5 million ha with an average growth rate of 0.39% a year, in the last 30 years. In the near future, the possibility for expanding areas under rice-based systems will remain very limited because of the scarcity of global water resources for agriculture, the expansion of urban and industrial sectors in Asia where land is already limited and the high costs of developing new lands that are suited for rice production in Sub-Saharan Africa and Latin America. The average growth rate of rice yield was 3.68% per year in the early 1980s, but it has decreased to 0.74% per year in the late 1990s. Several factors may contribute to the decline of the area under cultivation and in yield growth. The most important of these factors are: limited returns as we approach the yield potential of the high yielding varieties, declining productivity in intensive rice production systems, pressures from abiotic and biotic stresses, low returns in developing countries, increasing production costs in industrialized countries, and increasing public concern for the protection of environmental resources. One of the most effective means of addressing the issues in rice cultivation and raising the average yields at the farm level is through research and subsequent dissemination of the resulting data. Rice science has made considerable progress. In the area of rice varietal improvement, recent advances in hybrid rice and the new rice for Africa (NERICA) are just two examples of the successful contributions of science to the development of rice. Research could also help reduce the gap between the potential yield obtained on experimental stations and the actual yield obtained in the fields. This could be possible by developing and promoting rice integrated crop management (RICM) systems for improving productivity and reducing the production cost per unit of output. The need for a sustainable increase in rice production affects everyone. The International Year of Rice provide us with a chance to improve food security, alleviate poverty and preserve the environment for the billions of people for whom Rice is Life. Nguu Van Nguyen About the Author. Nguu Van Nguyen earned his PhD in Agronomy in 1976 from the University of the Philippines at Los Banos (UPLB). He has been serving for 2 years as Post-Doctoral Fellow, at the International Rice Research Institute and for other two as Assistant Professor at UPLB University. He has been working from 1980 to 1993 as agronomist at IITA (International Institute of Tropical Agriculture) and at Philippine Rice Research Institute. In 1991, he began his professional career at FAO, initially as rice agronomist, in West Africa, then as agricultural officer at Crop and Grassland Service. Since 2004 he is serving as Executive Secretary, International Rice Commission.

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Aldo Ferrero About the Author. Aldo Ferrero is at present Professor of “Weed Science”, “Agronomy” and “Crop Science” and head of the “Department of Agronomy, Forest and Land Management, University of Turin (Italy). He is coordinator of the rice FAO network “Medrice”, for Europe, Mediterranean, and Middle East countries. He possesses a wide experience in the field of the weed eco-biology and weed control in rice systems. He has been co-ordinator of European research projects funded by the European Union. He currently co-ordinates the project “EU-India Rice districts network promotion through agro-economical, cross cultural, and technical actions” (RICE-NET) aimed at studying agro-economical, cultural, and historical traits of the rice cultivation in the European and Indian rice districts, in order to improve socio-economical relationships between the two geographical areas. He is referee and member of the editorial board of several international journals.

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Student Opportunity: Short-Term Exposure to International Agriculture

Opportunities abound to apply crop science to solving many of the world’s food problems. International agricultural research centers (IARCs) provide a window through which students can see the need for improved agricultural productivity and briefly experience the rewards of working on difficult but important issues. In today’s world of highly technical graduate education, students find it difficult to obtain exposure to international agriculture due to the extreme constraints on their time. Programs for students that provide a short-term exposure to IARC strategies can have long-term benefits for the student as well as the international center. A short-term student exchange program between a US university and the International Rice Research Institute (IRRI) and a special course on rice (research to production) offered at IRRI provide students with unique insights for averting food riots in the future. Details of these educational efforts are described in this paper.     

Estimating Glycemic Index of Rice-Based Mixed Meals by Using Predicted and Adjusted Formulae

The estimation of glycemic index(GI) of rice-based mixed meal either by using predicted GI(GI_(pred)) or adjusted GI(GI_(adj)) formula is unclear.This study aimed to determine the glycemic response of rice in rice alone or mixed meals and to identify the appropriate formula for estimating the GI of rice-based mixed meals.The glycemic responses produced by the rice alone(red rice,fragrant white rice or parboiled rice) and the rice-based mixed meals(fried red rice,fried fragrant white rice or fried parboiled rice) which provided 25 g available carbohydrate were assessed in 11 healthy individuals.To determine the measured GI(GImeasured) of rice alone and rice-based mixed meals,participants underwent three repeated tests of a reference food(Glucolin~?).Tests were performed in random order on nine separate visits after an overnight fasting for at least 8 h.Capillary glucose at baseline(0 min),15,30,45,60,90 and 120 min from starting the meals was assessed and used to determine the incremental area under the curve(iAUC_(120)).The agreement between GImeasured and the estimation formulae(GI_(pred) or GI_(adj)) were determined using Bland-Altman analysis.The iAUC_(120) after consuming rice alone was significantly higher than the rice-based mixed meals except for fried fragrant rice,which was comparable to the rice alone(P 0.05).The GI_(measured) values of rice were categorized as medium(61 for parboiled rice,67 for fragrant white rice,and 68 for red rice).GI_(pred)(r = 0.40,P 0.01) and GI_(adj)(r = 0.41,P 0.01) were significantly correlated with iAUC_(120).The agreement between GI_(measured) and GI_(adj) is apparent suggesting the usefulness of GI_(adj) in estimating meal GI of rice-based mixed meals.     

Clearfield® rice: Its development,success, and key challenges on a global perspective

Weedy rice (Oryza sativa) is a close relative of domesticated rice and a noxious weed prevalent in rice fields in world regions where rice is grown. Weedy rice management has remained challenging to farmers, mainly due to the weed's physiological and morphological resemblance to rice cultivars. The introduction of Clearfield^® rice provides an alternative solution and an additional tool for integrated weed management. Clearfield^® rice-based programs result in the cleanest rice fields in the southern U.S. However, persistent application of the imidazolinone herbicides (imazethapyr, imazamox, and imazapic) in Clearfield^® rice raises concerns about the possible evolution of resistance to ALS-inhibitor herbicides in weedy rice and the transfer of resistance trait. The risk of resistant weedy rice evolution is much higher in Asia, Latin America, and other tropical regions where there is no winterkill and rice is planted at least twice each year. Herbicide carryover to rotational crops is also a concern. We summarized the progress of commercialization of Clearfield^® rice in 15 countries across the continents of America, Asia and Europe. In some countries, imidazolinone-resistant weedy rice outcrosses have been found abundant, thereby negating the utility of Clearfield^® technology. The persistence of imidazolinone herbicide residues in the soil is a concern in regions where multiple crops are planted in a year, or the following year. These challenges should be anticipated by countries that are considering adopting Clearfield^® rice technology. Issues associated with gene escape, resistance evolution in weedy rice, and herbicide carryover to rotational crops remain to be resolved. Research to achieve sustainable solutions for weedy rice management, must be continued and intense educational programs for growers must be sustained.     

Increasing water productivity for paddy irrigation in China

This paper introduces the research on practices to increase water productivity for paddy irrigation in China and summarizes the experience on implementation of the alternate wetting and drying (AWD) irrigation technique. The widespread adoption of the AWD practice on 40% of the rice growing area provides an opportunity for China to produce more food in the water-surplus south where it is wet and the traditional based paddy field agriculture is dominant. Physical and institutional measures leading to increasing water and land productivity in rice-based systems are discussed. Research studies show that AWD practice does not reduce rice yield, but does increase the productivity of water. Water use and thus water charges can be reduced. However, experience shows that demonstrations and training are needed to encourage farmer adoption. Furthermore, there are a range of complementary policies and practices, such as volumetric pricing or farm pond development, which provide incentives for adoption of AWD. Finally, there remain many scientific issues to be addressed. Application of the AWD technique in some regions is still very difficult because of both bio-physical and socio-economic problems. In conclusion, the widespread adoption of AWD is only a first step in the continuing effort to find practices that will increase water productivity for paddy irrigation in China.Dr. Yuanhua Li was a Professor and Dean in Wuhan University of Hydraulic and Electric Engineering from 1996 to 2000. After that, he has been a Professor and Deputy Director General of the National Centre for Irrigation and Drainage Development, Ministry of Water Resources, China. He has been doing research on irrigation principally for paddy since 1982.Dr. Randolph Barker is an agricultural economist and Professor Emeritus Cornell University. From 1966 to 1978 he served as head of the Economics Department, International Rice Research Institute, Los Banos, Philippines and from 1995 to 2004 was principal researcher, International Water Management Institute, Colombo, Sri Lanka.     

Plant Parasitic Nematodes in Rice-Wheat Based Cropping Systems in South Asia

Summary

Rice-wheat based cropping systems in South Asia are among the most highly evolved production systems in the world. The productivity growth of these systems in South Asia is declining due to several factors including the biotic stresses of plant parasitic nema-todes. This article reviews the research on rice and wheat nematodes in a cropping systems perspective and identifies nematodes that have wide host ranges and are greatly influenced by the crop rotations and sequences. These polyphagous nematodes can cause significant damage to rice and (or) wheat crops, either alone or in combination with other microorganisms. The research projects on pest management in the region lack inter-disciplinarity and it is important for nematologists to become integral members of interdisciplinary teams on improving the productivity and sustainability of the rice-wheat cropping systems.     

Defensive Role of Plant Hormones in Advancing Abiotic Stress-Resistant Rice Plants

Consistent climatic perturbations have increased global environmental concerns, especially the impacts of abiotic stresses on crop productivity. Rice is a staple food crop for the majority of the world’s population. Abiotic stresses, including salt, drought, heat, cold and heavy metals, are potential inhibitors of rice growth and yield. Abiotic stresses elicit various acclimation responses that facilitate in stress mitigation. Plant hormones play an important role in mediating the growth and development of rice plants under optimal and stressful environments by activating a multitude of signalling cascades to elicit the rice plant’s adaptive responses. The current review describes the role of plant hormone-mediated abiotic stress tolerance in rice, potential crosstalk between plant hormones involved in rice abiotic stress tolerance and significant advancements in biotechnological initiatives including genetic engineering approach to provide a step forward in making rice resistance to abiotic stress.     

转基因水稻环境安全评价研究进展

水稻是世界上主要的粮食作物之一。自20世纪80年代以来,中国全方位开展转基因水稻的研发,已经培育出抗病、抗虫、抗除草剂和抗逆的转基因水稻品种,这将为提高中国水稻的生产力和确保粮食安全做出重要贡献。但转基因水稻的环境安全问题备受关注。通过分析转基因水稻给人类带来的利与弊,并从转基因水稻的杂草化与基因漂移、对生物多样性和土壤微生物的影响等方面评价转基因水稻的环境安全性,以期为中国转基因水稻的安全应用提供参考。     

Evaluation of green manure technology in tropical lowland rice systems

Green manure (GM) is not superior to organic fertilizer in terms of agronomic efficiency. Use of GM destabilizes rice yield, and has higher unit production cost than N fertilizers. It produces higher cereal yields in farmers' field, but gives negative or trivial returns in the short-term conditions. When compared with grain legumes (GL) grown under similar conditions, GM is not economical both in the short- and long-term conditions. Integrating GL in the existing cropping system without disturbing the main crops in the system appears to have a greater chance of adoption, and may also provide long-term economic benefits to low-land rice-based systems. The economic feasibility of GM can be improved by enhancing its use as food and feed, which will improve its short-term advantage. The lesson for developing technologies in future is that they should have economic benefits in the short-term, otherwise these will be rejected by farmers, despite their long-term advantages.     

Understanding the relationship between volunteers’ motivations and learning outcomes of Citizen Science in rice ecosystems in the Northern Philippines

This study relies on the Flying Beauties Citizen Science project conducted in the Philippines to assess personal motivations and learning outcomes of volunteers who were involved in documenting butterflies and dragonflies in rice ecosystems. While evaluation of motivations of volunteers in Citizen Science is not new, at least in affluent western countries, little is done in investigating volunteers’ motivations and learning outcomes of Citizen Science projects in low-income countries. Using surveys, we collected data from volunteers that were analysed qualitatively and quantitatively. We adopted a two stages evaluation format—before and after volunteers finished the project exercise. We compared pre-motivations to motivations attained and changes in level of knowledge before and after the project ended. We use Spearman’s Rho, Kendall’s Tau—nonparametric tests to draw correlations between variables. The results showed that key determinants that drove people to volunteer in the project were (a) learning about species and (b) being part of scientific research and the principal learning outcome was improved awareness about ecosystem functions of the species.     

Effects and fate of biochar from rice residues in rice-based systems

Although crop residues constitute an enormous resource, actual residue management practices in rice-based systems have various negative side effects and contribute to global warming. The concept of a combined bioenergy/biochar system could tackle these problems in a new way. Rice residues would be used for energy production, thereby reducing field burning and the use of fossil fuels, and the biochar by-product could help to improve soils, avoid methane emissions, and sequester carbon in soils. To examine some of these promises, we conducted field experiments from 2005 to 2008 in three different rice production systems. Objectives were to study the effect of biochar from rice husks on soil characteristics, assess the stability of carbonized rice residues in these different systems, and evaluate the agronomic effect of biochar applications. The results showed that application of untreated and carbonized rice husks (RH and CRH) increased total organic carbon, total soil N, the C/N ratio, and available P and K. Not significant or small effects were observed for soil reaction, exchangeable Ca, Mg, Na, and the CEC. On a fertile soil, the high C/N ratio of CRH seemed to have limited N availability, thereby slightly reducing grain yields in the first three seasons after application. On a poor soil, where the crop also suffered from water stress, soil chemical and physical improvements increased yields by 16-35%. Together with a parallel study including methane and CO₂ emission measurements at one site, the results strongly suggest that CRH is very stable in various rice soils and systems, possibly for thousands of years. However, the study also showed that CRH was very mobile in some soils. Especially in poor sandy soil, about half of the applied carbon seemed to have moved below 0.30 m in the soil profile within 4 years after application. We concluded that biochar from rice residues can be beneficial in rice-based systems but that actual effects on soil fertility, grain yield, and soil organic carbon will depend on site-specific conditions. Long-term studies on biochar in field trials seem essential to better understand biochar effects and to investigate its behavior in soils.     

SRI as a methodology for raising crop and water productivity: productive adaptations in rice agronomy and irrigation water management

The System of Rice Intensification (SRI), developed in Madagascar almost 30 years ago, modifies certain practices for managing plants, soil, water, and nutrients with the effect of raising the productivity of the land, labor, and capital devoted to rice production. Certain production inputs are reduced—seeds, inorganic fertilizer, water, and fuel where water is pumped—with increased yield as a result. This paper introduces the subject of SRI, which is then addressed variously in the articles that follow. SRI is gaining interest and application in over 40 countries around the world. Its practices make soil conditions more aerobic and promote greater root growth, as well as larger, more diverse communities of beneficial soil biota. These below-ground changes support more productive phenotypes above-ground for practically all rice genotypes (cultivars) tested so far, with supportive evidence accumulating both from scientific institutions and field applications. SRI methodology remains controversial in some circles, however, because of the transformational change it introductions into traditional lowland rice production systems. This issue of PAWE brings together the results of formal research on SRI in a number of countries (Part I) and also reports on initiatives by government agencies, NGOs, universities, or the private sector, bringing knowledge of SRI to farmers in a wide range of agroecological circumstances (Part II). This introduction presents the basic principles that underlie SRI and discusses the nature of this innovation as well as considers some of the issues in contention. SRI continues to evolve and expand, being a work in progress. Its concepts and methods are being extended also to upland (rainfed) rice production, as well to other crops. Accordingly, SRI should not be regarded or evaluated in conventional terms as if it were a typical component technology. It is understood more appropriately in terms of a paradigm shift for rice production. In particular, it calls into question the long-standing belief that rice is best produced under continuously flooded conditions.     

日本转基因水稻研究现状与发展趋势

介绍了世界转基因作物栽培概况,阐述了日本转基因植物利用以及日本转基因食品的安全审查及标示现状。并以柳杉花粉过敏症缓和米以及多抗性转基因水稻的开发为例,重点介绍了日本转基因水稻研究现状与发展趋势。最后简要讨论了新型植物育种技术及其应用前景。     

全球水稻生产与稻作生态系统概况

1961—2001年，全球水稻总产、面积和单产分别增长171．3％，30．9％和107．0％。在总产增长中，收获面积增加贡献27．8％，单产提高贡献72．2％，水稻总产增长主要由单产的提高所致。亚洲是主要的产稻区，其水稻总产和收获面积分别占全球的90％和91％。全球各产稻国水稻平均单产差异很大，水稻增产关键在于提高中低产国家和地区的水稻单产水平。全球稻田中，灌溉稻田、雨灌稻田、早稻田和深水稻田分别占54％，3l％，11％和4％。不同水稻生态系统的地区分布中，灌溉稻和雨灌稻主要分布在亚洲，分别占93．0％和95．5％，深水稻主要分布在亚洲和非洲，分别占67．3％和25．0％，早稻主要分布在亚洲、美洲和非洲，分别占57．1％，20．0％和19．1％。     

Multidisciplinary assessment of agricultural innovation and its impact: a case study of lowland rice variety WITA 9 in Côte d’Ivoire

ABSTRACT

Information on comprehensive evaluation of agricultural innovations is often limited. This study provides an overview of multidisciplinary evaluation of a lowland rice variety, WITA 9 (released in Côte d’Ivoire in 1998), with respect to its agronomic performance, grain quality, resistance to diseases, adoption by farmers, impact on productivity and farmers’ income, and marketability. WITA 9 had the highest paddy yield among the tested varieties including an international check (IR 64) and recently developed varieties adapted to this country. WITA 9 had a higher amylose content (26–28%) than others tested. This study confirmed its resistance to bacterial leaf blight, Rice yellow mottle virus (RYMV), and rice blast. A household survey showed that the adoption rate was 24%, its paddy yield advantage was 0.7 t ha^–1, and its adoption increased farmer’s income by US$ 91 ha^–1 per season. A market study showed that consumers’ willingness to pay was higher for WITA 9 than any other locally produced rice variety and comparable to imported rice in one of two markets. We conclude that WITA 9 is an ideal innovation for enhancing productivity and rice import substitution in Côte d’Ivoire. An effective seed delivery system and enhancing farmers’ and consumers’ awareness of this variety are vital for accelerating impact.     

Utilizing rainfall and alternate wetting and drying irrigation for high water productivity in irrigated lowland paddy rice in southern Taiwan

Taiwan’s average annual rainfall is high compared to other countries around the world; however, it is considered a country with great demand for water resources. Rainfall along with alternate wetting and drying irrigation is proposed to minimize water demand and maximize water productivity for lowland paddy rice cultivation in southern Taiwan. A field experiment was conducted to determine the most suitable ponded water depth for enhancing water saving in paddy rice irrigation. Different ponded water depths treatments (T_2 cm, T_3 cm, T_4 cm and T_5 cm) were applied weekly from transplanting to early heading using a complete randomized block design with four replications. The highest rainwater productivity (2.07 kg/m³) was achieved in T_5 cm and the lowest in T_2 cm (1.62 kg/m³). The highest total water productivity, (0.75 kg/m³) and irrigation water productivity (1.40 kg/m³) was achieved in T_2 cm. The total amount of water saved in T_4 cm, T_3 cm and T_2 cm was 20, 40, and 60%, respectively. Weekly application of T_4 cm ponded water depth from transplanting to heading produced the lowest yield reduction (1.57%) and grain production loss (0.06 kg) having no significant impact on yield loss compared to T_5 cm. Thus, we assert that the weekly application of T_4 cm along with rainfall produced the best results for reducing lowland paddy rice irrigation water use and matching the required crop water.     

稻谷的开发利用

稻谷是世界上的主要农产品之一,具有巨大的开发潜力和利用价值。从米淀粉功能食品的开发、米糠健康食品的开发及稻壳深度开发几方面介绍了世界先进国家利用高新技术对稻谷进行深度加工和综合利用情况。     

More Rice,Less Water—Integrated Approaches for Increasing Water Productivity in Irrigated Rice-Based Systems in Asia

Abstract

The water crisis is threatening the sustainability of the irrigated rice system and food security in Asia. Our challenge is to develop novel technologies and production systems that allow rice production to be maintained or increased in the face of declining water availability. This paper introduces principles that govern technologies and systems for reducing water inputs and increasing water productivity, and assesses the opportunities of such technologies and systems at spatial scale levels from plant to field, to irrigation system, and to agro-ecological zones. We concluded that, while increasing the productivity of irrigated rice with transpired water may require breakthroughs in breeding, many technologies can reduce water inputs at the field level and increase field-level water productivity with respect to irrigation and total water inputs. Most of them, however, come at the cost of decreased yield. More rice with less water can only be achieved when water management is integrated with (i) germplasm selection and other crop and resource management practices to increase yield, and (ii) system-level management such that the water saved at the field level is used more effectively to irrigate previously un-irrigated or low-productivity lands. The amount of water that can be saved at the system level could be far less than assumed from computations of field-level water savings because there is already a high degree of recycling and conjunctive use of water in many rice areas. The impact of reducing water inputs for rice production on weeds, nutrients, sustainability, and environmental services of rice ecosystems warrants further investigation.