Dissertations / Theses on the topic 'Rice cropping system'

System of Rice Intensification (SRI) has been introduced and practiced throughout Thailand. However, the conventional transplanting system is well-accepted among Thai farmers over the country. This paper quantifies and compares costs and benefits of SRI and the conventional system of rice cultivation in Thailand to find the best system for a farmer, the environment and a society. The scope of this paper includes a farmer’s profit, the environmental damages and a society’s net benefits categorized in clay soil and sandy loam conditions. The farmer’s profit consists of a production cost and income. The amount of fertilizer application, level of lethal dose and climate change cost are regarded as environmental damage components. The society has concerned over the farmer’s profit and the environmental cost in a decision. The study uses cost-benefit analysis to investigate mean and variation of profit and cost in monetary term. Monte Carlo simulation is utilized for quantifying risk in each scenario. The study finds that SRI saves the production input and increases yield gain significantly. The most impressive results are a reduction in water consumption and number of seeds. Also, the environmental damage caused by this system is lower due to less amount of chemical fertilizer and pesticide applications as well as a low rate of methane gas emission. Sensitivity analysis shows that SRI has better performance under best and worst case scenarios for both types of soil (clay soil and sandy loam). However, the system contains the highest risk of the farmer’s profit. In conclusion, SRI is more beneficial and efficient than conventional system. Still, risk aspects should be considered in decision making. This study can be employed as a framework for government or any parties, who are interested or have willingness to conduct a field study of SRI and the conventional rice cropping system or for the further study about the integrated system (a combination between SRI and conventional system).

Rice and maize are global staple food and play an important role in world’s food security strategy. Vietnam is one of rice leading export countries but annually it has to import a considerate amount of maize for cattle food processing. Red River Delta in the north of Vietnam is the second rice bucket of the country, which is responsible formore than 20% of total rice production. The priority crops in the areas are rice and maize and rice-maize system is the leading cropping system in the area. Currently, it is reported that the rice-maize cropping system is not sustainable and its profit is reducing in most of production areas in the Red River Delta. Improving rice cropping system aims is not only to increase rice and maize yields and production but also to improve the land use efficiency, decline the cost of the production and to increase system sustainability. To increase sustainability there must be a linkage of various factors. This review emphasizes on increasing rice-maize crop sustainability by applying appropriate agriculture practices such as reducing chemical fertilization and intensive tillage
Gạo và ngô là nguồn lương thực chính cho toàn cầu và đóng một vai trò quan trọng trong chiến lược an ninh lương thực của thế giới. Việt Nam là một trong những nước dẫn đầu về xuất khẩu gạo nhưng hàng năm vẫn phải nhập một số lượng lớn ngô để chế biến thức ăn gia súc. Đồng bằng sông Hồng là một trong hai vựa lúa lớn của Việt Nam sản xuất khoảng 20% sản lượng lúa gạo của cả nước. Ở đồng bằng sông Hồng, lúa và ngô là hai cây trồng chính là hệ canh tác lúa-ngô là cơ cấu cây trồng hàng đầu trong vùng. Tuy nhiên, trong những năm gần đây, rất nhiều đánh giá cho thấy hệ thống canh tác lúa-ngô là hệ thống canh tác không bền vững và các lợi nhuận của mang lại từ cơ cấu canh tác ở hầu hết các khu vực sản xuất ở vùng đồng bằng sông Hồng của Việt Nam đã và đang giảm dần. Do đó, việc cải thiện cơ cấu canh tác lúa-ngô không chỉ nhằm mục đích tăng năng suất lúa và ngô mà còn nâng cao hiệu quả sử dụng đất, giảm chi phí sản xuất và tăng cường hệ thống canh tác bền vững. Tuy nhiên, để tăng tính bền vững của hệ thống canh tác thì phải liên kết nhiều yếu tố khác nhau. Bài viết này dựa vào các kết quả nghiên cứu của các tác giả khác nhau để đưa ra những giải pháp tích cực làm tăng tính bền vững của hệ thống canh tác lúa-ngô bằng cách áp dụng các phương pháp canh tác hợp lý như giảm sử dụng phân hóa học và các biện pháp canh tác thâm canh như áp dụng phương pháp làm đất tối thiểu

The main challenge of modern agriculture lies in the need of enhancing crop productivity to guarantee food security while achieving the sustainability of cropping systems in a changing climate. In a recent speech to the 21st Conference of Parties to the United Nations Framework Convention on Climate Change (COP21) held in Paris, the president of the United States declared that for all the challenges we face, the growing threat of climate change could define the contours of this century more dramatically than any other. This is why He hopes that all the countries in the world, united in common effort and by a common purpose, will not condemn the next generation to a planet that’s beyond its capacity to repair. Agricultural activities deep influence the carbon, water and nutrients cycles at global level, then still play a vital role in the survival of humankind. The need to double food production by 2050 is entrusted to agriculture, which accounts for 14% of greenhouse gases emission and is considered as the economic sector most uniquely susceptible to changes in climate patterns, due to its dependence on the biophysical environment. Standing first among all food grain crops, rice (Oryza sativa L.) is in the spotlight due to the projected decrease in production in top producing countries and to the environmental sustainability of rice cropping systems, in light of the use of large amount of water for irrigation and of the contribution to the emission of greenhouse gases (GHGs) at the global level. The improvement of the water and nutrient management in paddy rice cropping systems is then considered as a necessary step to mitigate agriculture’s GHG emissions, as reported by the United Nations Foundation. The scaling up of mitigation strategies from farmers’ level to national policy makers needs the support of the scientific community, who is in charge to develop research to address these paramount questions. In this framework, the adoption of cropping system simulation models as a reference to assess both the productivity and the environmental impacts of cropping systems under a variety of management and climatic scenarios seems unavoidable, as they are the only available tools to reproduce the nonlinear responses of biophysical processes to boundary conditions. They also represent a viable solution to design and test alternate strategies to mitigate the emission of GHGs and to optimize the use and management of resources in agriculture. This PhD program enables the scientific community to move forward the integration of available biophysical models to dynamically simulate the different components of the rice cropping system, considering the multiple, mutual interactions among system’s domains which determine rice crop yield and environmental drawbacks. The final achievement is the delivery of a software targeting this purpose, which is documented in the last chapter; the objective of this research product is to give a modelling solution to simulate the comprehensive set of biophysical processes involved with the paddy rice cropping system, considering the crop development and growth, the soil water dynamics, the effects of fertilizers on nitrogen leaching and the emission of greenhouse gases at field scale, considering the impact of alternate farmer management strategies. During the work some deficiencies in current models were highlighted and solved, such as the unjustified complexity of widely adopted crop simulators or the lack, within them, of algorithms for the simulation of processes which significantly contribute to explain the variability of rice yield. The output of this work is made available through software components and modular modelling solutions: this choice, representing the state of the art of software engineering science, removes technological bottlenecks which usually prevent advances in agricultural system modelling and fosters international collaborations between research centers while laying the basis for further developments.

Maintaining phosphorus (P) fertility in northern Great Plains (NGP) dryland organic cropping systems is a challenge due to high pH, calcareous soils that limit P bioavailability. Organic P fertilizers, including rock phosphate (RP) and bone meal (BM) are sparingly soluble in higher pH soils. Certain crops species have demonstrated an ability to mobilize sparingly soluble P sources. Objectives of this project were to 1) evaluate the effect of green manure (GM) crops and organic P fertilizers on the P nutrition of subsequent crops, and 2) investigate P fertility differences between organic and non-organic cropping systems. A two-year cropping sequence was conducted on an organic farm in north-central Montana (mean pH=6.6; Olsen P=16 mg kg⁻¹). Spring pea (Pisum sativum L), buckwheat (Fagopyrum esculentum L.), yellow mustard (Sinapis alba L.) and tilled fallow were fertilized with 0, 3.1 and 7.7 kg P ha⁻¹ as RP, grown to flat pod stage and terminated with tillage. Winter wheat (Triticum aestivum L.) was grown on these plots in year two. Phosphorus uptake of winter wheat was enhanced (P>0.05) by RP following buckwheat only (P=0.02) at 7.7 kg P ha⁻¹ compared to 0 P. Results indicate buckwheat can enhance P in a subsequent crop. A greenhouse pot experiment in a low P soil (Olsen P=4 mg kg⁻¹) consisted of four green manures; buckwheat, spring pea, wheat, and a non-crop control fertilized with 7.0 and 17.5 kg available P ha⁻¹ as RP, 13.0 and 32.5 kg available P ha⁻¹ as BM and 10 and 25 kg available P ha⁻¹ as monocalcium phosphate (MCP). Green manures were harvested, dried, analyzed for nutrient content, and returned to pots. Pots were seeded with wheat. Phosphorus uptake in wheat following all crops was enhanced by MCP (P<0.05). Phosphorus uptake of wheat following buckwheat was enhanced by all P sources over the control. Buckwheat demonstrates the capacity to increase the availability of organic P fertilizers. Soil sampling of organic and non-organic no-tillage (NT) cropping systems was conducted in two separate studies to determine differences in P availability between management systems. Soil analysis determined available P tends to be lower in non-fertilized systems.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第6908号
農博第926号
新制||農||741(附属図書館)
学位論文||H9||N3032(農学部図書室)
16025
UT51-97-H292
京都大学大学院農学研究科熱帯農学専攻
(主査)教授 海田 能宏, 教授 古川 久雄, 教授 堀江 武
学位規則第4条第1項該当

Intensive rice-based cropping systems in the Eastern Indo-Gangetic Plains (Eastern India and Bangladesh) have played a pivotal role in increasing food security in that region but sustainability of these cropping systems is under threat. Conservation agriculture (CA) ‒ cropping systems based on minimum soil disturbance, crop residue retention and suitable crop rotations ‒ has been proposed to address these challenges but there has been limited research on its effects on crop productivity and soil properties in Bangladesh. This thesis examines the effects of implementing minimum soil disturbance and increased crop residue retention on soil properties and crop performance over three years in two rice-based rotations. Two field trials were conducted during 2010-2013 in contrasting triple-cropping rotations (with crop number in parentheses): 1. Legume-dominated rotation ‒ lentil (1, 4 and 7)-mungbean (2 and 5)-monsoon rice (3 and 6) in an Alluvial soil region; and 2. Cereal-dominated rotation ‒ wheat (1, 4 and 7)-mungbean (2 and 5)-monsoon rice (3 and 6) in the High Barind Tract (HBT) region of north-west Bangladesh. There were three tillage treatments in main plots ‒ strip tillage (ST), bed planting (BP) and conventional tillage (CT). Sub-plots comprised two levels of residue ‒ high residue (HR) and low residue (LR). Puddled transplanted rice was applied in CT and unpuddled transplanted rice in ST and BP. This thesis focuses on soil properties and the growth and yield of the cool-dry season crops in each year, namely lentil on the Alluvial soil and wheat on the HBT soil. During the first two growing seasons treatment effects on soil properties and crop performance were marginal but became clearly apparent in the third year. In the legume-dominated system, grain yield of lentil was 15 % higher in HR than LR averaged across all tillage types in Year 2. In Year 3, the yield of lentil was higher by 23 % in ST and 18 % in BP compared with CT. In the cereal-dominated system, grain yield was not affected by tillage and residue treatments in Year 1. However, in Year 2, grain yield of wheat was depressed by 39 % in BP due to poor crop establishment. In Year 3, the yield of wheat was greater by 9 % in ST and 7 % in BP than CT; wheat yield of HR was 3 % higher compared to LR. The soil water content (SWC) increased and bulk density (BD) and penetration resistance (PR) decreased in surface soil (0-5 cm) with ST and at 5-10 cm and 10-15 cm soil depth with BP, compared to CT. The retention of more intact residue left between the plant rows conserved more SWC and lowered the soil BD and PR of surface soil under ST. Implementation of ST and BP with HR treatment gradually improved soil physical properties and alleviated puddling effects that characterise current practices (CT and LR) in rice-based systems. Such improvements are probably due to increases in soil organic carbon (SOC) and total nitrogen (TN) with ST and BP. Greater root growth under BP was not associated with increased grain yield. However, the overall improvement in soil surface conditions and greater root growth at depth may have allowed extraction of water and nutrients from a larger soil volume in ST resulting in a gradual increase in crop productivity over time. After 2.5 years in both legume- and cereal-dominated rotations, the SOC concentrations, SOC-stocks and labile C fraction (water soluble carbon ‒ WSC) at 0-7.5 cm soil depth were greater in ST than CT. By contrast, the SOC concentrations and storage, and WSC increased at 7.5-15 cm soil depth in BP compared to CT and ST. Soil C losses through the emission of CO2 were greater in CT than ST and BP. The relative efficacy of tillage in storing SOC was in the order of ST>BP>CT. High residue retention increased SOC concentrations, SOC storage, WSC and CO2 emission from soil. In the cereal-dominated rotation, ST sequestered 0.44-0.20 Mg C/ha annually while CT caused 0.41-0.66 Mg C/ha loss at 0-15 cm soil depth. In contrast to the legume-dominated rotation, neither CT nor ST sequestered SOC but ST reduced the loss by 0.40 Mg C/ha annually compared to CT. Based on the C balance, it is estimated that annual carbon inputs of 3.8 Mg C/ha under ST and 6 Mg C/ha under CT condition in the legume-dominated system, and 1.0 Mg C/ha under ST and 7.7 Mg C/ha under CT condition in the cereal-dominated system, would be required to maintain SOC at the antecedent level. In the present study, ST and HR treatment increased TN, N-stocks, total soluble nitrogen and potentially mineralizable nitrogen (PMN) in the surface soil (0-7.5 cm) as compared to CT and LR at the end of Crop 7. In ST and HR, the lower mineral N (NH₄-N and NO₃-N) and larger PMN indicated the greater immobilization or less mineralization of N, or both, and restricted the potential losses of N. Retention of HR resulted in positive N balance while LR caused a negative N balance. Regardless of treatment variation, the soil TN, N-stocks and available N were greater in the cereal-dominated cropping system than in the legume-dominated system, probably due to carry-over of higher N fertilizer rates applied to the cereal crop, and greater above- and below-ground biomass. The changes of soil TN due to residue were only apparent in legume-dominated system. The greater input derived from nitrogenous residue of mungbean and lentil may account for the positive effects of HR in the legume-dominated system. Application of ST and HR has potential for increasing carbon sequestration and N accumulation while reducing N losses, hence improving soil properties and thereby crop growth and yields, within 2-3 years in rice-based systems of Bangladesh. However, further studies are required over a longer time period to evaluate the performance of unpuddled rice rotated with ST non-rice crops with a range of residue retention levels under different soil, climatic, and socio-economic conditions in the eastern Indo-Gangetic Plains.

The energy analysis aims to compare the performance between productive units and activities, searching an approach to link the energy with the economic, social and cultural parameters in the management of natural resources in economic systems. The main question that arises and guides this dissertation is the analysis of the energy produced and consumed during the production process of major crops in the state of Rio Grande do Sul, namely, rice, soybeans and wheat, opposed to the economic results of such activities. The research was exploratory and based on multi-case studies with the use of literature review, laboratory analysis and interviews with producers. The choice of the production units studied favored the production systems that adopt modern technologies, where precision agriculture and controlled use of natural resources, such as water, are developed. Calculations were performed considering the energy available with workforce, seeds, fertilizers and pesticides (herbicides, insecticides and fungicides) machinery and equipment as well as fuels (lubricating oils, greases and diesel). To obtain the results of economic activities the added-value theory was used. The results demonstrate that the activity of soybean in no-tillage system with crop rotation achieved the highest energy efficiency between 25.58 MJ.ha-1 and 38.39 MJ.ha-1, whereas wheat culture showed the lowest efficiency with 3.13 MJ.ha-1. Regarding the economic performance of crops, soybeans showed the highest economic efficiency 2,47 and wheat the lowest 1,14. It is worth mentioning the significant economic results achieved by the rice crop, expressed by the high added-value obtained per unit area (VAL/ha R$ 3,802.00) due to its high physical productivity. In spite of having positive energy indicators, significant expenses on fertilizer, fuel and pesticides were observed in all properties studied. Thus, we reinforce the importance of the debate on social and environmental sustainability of the systems studied, especially when analyzed from the perspective of energy expenses of non-renewable resources and social problems attributed to workforce.
A presente análise tem a finalidade de comparar o desempenho entre unidades e atividades produtivas, interligando os parâmetros energéticos aos econômicos, sociais e culturais, na gestão dos recursos naturais nos sistemas de produção. Sendo assim, a dissertação tem como questão norteadora analisar a relação entre a energia produzida e consumida durante o processo de produção das principais culturas de cereais do Estado do Rio Grande do Sul, a saber: trigo, arroz e soja, em contraposição aos resultados econômicos das respectivas atividades. A pesquisa foi do tipo exploratório, a partir de estudos de multicaso, com uso de pesquisa bibliográfica, análises de laboratório e entrevistas com produtores. A escolha das unidades de produção estudadas privilegiou as que adotam sistemas produtivos tecnificados, onde se desenvolve a agricultura de precisão e a utilização controlada de recursos naturais, como a água. Para determinar os resultados de análises energéticas foram realizados os balanços energéticos e as eficiências culturais e energéticas das culturas, ao passo que para os resultados econômicos das atividades estudadas foi utilizada a teoria do Valor Agregado. Os resultados demonstram que a atividade da soja, em sistema de plantio direto com rotação de culturas, alcançou a maior eficiência energética, entre 25,58 MJ.ha-1 a 38,39 MJ.ha-1, sendo que a relação de menor eficiência foi a cultura do trigo, com 3,13 MJ.ha-1. Em relação ao desempenho econômico das culturas, a soja igualmente mostrou a melhor eficiência econômica 2,47 e o do trigo 1,14 a menor. Cabe destacar os significativos resultados econômicos obtidos pela cultura do arroz, expressos pelo alto valor agregado obtido por unidade de área (VAL/ha de R$ 3.802,00) em função de sua alta produtividade física. Apesar dos indicadores energéticos serem positivos, houve significativos gastos com fertilizantes, combustíveis e agrotóxicos em todas as propriedades estudadas. Desta forma reforça-se a importância do debate sobre a sustentabilidade socioambiental dos sistemas estudados, principalmente quando analisados sob a ótica dos gastos energéticos de bens não-renováveis e da problemática social atribuída a mão-de-obra.

The combination of rising population and increasing food demand has placed tremendous pressure on the soil resource in Bangladesh, especially floodplain soils where rice may be grown year round. Although these floodplain soils contain minerals high in potassium (K) such as micas, K deficiency in rice paddy soils is increasing throughout Bangladesh. Harvesting of straw from fields exacerbates the removal of nutrients including K, and intensive cropping with unbalanced fertilizer has resulted in depletion of "readily available" K in large areas. Five representative floodplain soils in rice production were sampled by horizon to determine physical, chemical and mineralogical properties, assess soil K, investigate plant available K, and understand impacts of redox on K fixation and release. Total and nonexchangeable K were determined using concentrated hydrogen fluoride (HF) digestion and 1.0 M HNO3 digestion, respectively, along with NH4OAcextractable K. Cation exchange capacity under both oxidized and reduced conditions was determined. Assessment of adsorption and release of K as a function of redox was done in conjunction with seven different concentrations of potassium chloride (KCl) solution and three different soils. Significant amounts of K were present in all fractions of silts and clays. Potassium concentration was greatest in the coarse clay fraction. High HNO3- extractable K suggested that much of the K in soils was from mica interlayers. Acidic soils contained less K in all fractions than the less weathered, calcareous soils. The clay fractions exhibited mostly mica, vermiculite, smectite and kaolinite. The cation exchange capacity (CEC) of reduced soils was less under oxidized condition, due to collapse of the interlayer in response to increased layer charge upon structural Fe reduction. The adsorption of K was greater for calcareous soils under both oxidized and reduced conditions than for the acidic soils. Less native K was extracted under oxidized conditions than under reduced conditions. Less adsorption under reduced conditions may be due to an increase in solution Fe2+ which can compete with K+ for exchange sites on clays.

This thesis investigated the impact of organic sources of nutrients on greenhouse gas emissions (carbon dioxide, nitrous oxide and methane), nitrogen use efficiency and biomass production in subtropical cropping soils. The study was conducted in two main soil types in subtropical ecosystems, sandy loam soil and clay soil, with a variety of organic materials from agro-industrial residues and crop residues. It is important for recycling of agro-industrial residues and agricultural residues and the mitigation of greenhouse gas emissions and nitrogen use efficiency.

Face aux besoins croissants pour une production agricole durable, les systems de culture évoluent vers des systèmes qui accomplissent des objectifs environnementaux et agricoles multiples. La recherche en conception de systèmes de cultures (CSC) s'intéresse à l'effet des pratiques et de l'environnement sur les systèmes de culture et leur performance. L'interaction entre production et services ecosystémiques, et la quantification de ces relations, sont un aspect clé de ce domaine de recherche. Une variété d'approches ont été théorisées, tels que l'utilisation de modèles et la mobilisation de connaissances expertes. Les modèles permettent de tester rapidement et à faible coût l'effet de pratiques agricoles dans une variété de conditions, mais l'application de conclusions théoriques à la parcelle peut être limitée par des contraintes locales ainsi que des obstacles à la communication chercheur-agriculteur. Mobiliser les agriculteurs et autres acteurs pertinents pour la CSC peut aider à surmonter ces obstacles ; cependant, cela limite l'innovation au cadre des connaissances expertes.L'objectif de cette thèse est de combiner la modélisation et des méthodes participatives pour une méthode de CSC qui exploite le potentiel de la modélisation numérique tout en s'assurant que les solutions proposées prennent en compte les contraintes environnementales et socioéconomiques. Après avoir revu l'état d'avancement de la recherche en prototypage et en CSC, nous proposons un cadre méthodologique divisé en quatre parties ; a) combiner une typologie des pratiques et un modèle conceptuel pour évaluer la diversité des pratiques, contraintes et trade-offs dans une zone de production ; b) acquérir des données de terrain pour quantifier les trade-offs pertinents entre production et services écosystémiques ; c) sélectionner et préparer un modèle numérique approprié pour simuler les effets des pratiques sur la production et l'apport de services ; et d) évaluer si l'interaction d'agriculteurs avec le modèle numérique peut générer des systèmes de culture potentiels qui répondraient aux objectifs agro-environnementaux posées (apport d'un service écosystémique) ainsi qu'être acceptables pour les agriculteurs qui les adapteraient à l'expérimentation dans leurs parcelles.The systèmes agroforestiers à base de café (cafés/arbres d'ombrage) du Costa Rica central ont étés le système de culture choisi pour répondre à ces questions. Les systèmes agroforestiers offrent de nombreuses occasions d'étudier et évaluer les services écosystémiques apportés, en plus de la production principale. L'association de deux cultures pérennes place l'évaluation de la performance à long terme et de la durabilité des systèmes au centre de la question. La culture du café au Costa Rica fait vivre une part importante de la population, et est aussi basée sur la gestion intensive d'une culture à haute valeur d'exportation, vulnérable aux fluctuations des prix sur le marché mondial ainsi qu'au changements climatiques. Des pentes raides et une saison des pluies importante créent des problèmes d'érosion significatifs ; cependant, certaines pratiques de contrôle de l'érosion (utilisation d'arbres d'ombrage et d'adventices) impactent la production de café. La réconciliation de ces deux aspects nous offrent l'occasion de tester notre cadre méthodologique dans une situation où une solide argumentation technique serait nécessaire pour encourager les expérimentations dans les parcelles. Enfin, le dernier chapitre porte une réflexion d'ensemble sur l'importance de choisir et préparer correctement un modèle agronomomique adéquat, les application potentielles de cette méthodologie, ainsi que les recommandations que nous avons pu effectuer en termes de pratiques de contrôle de l'érosion dans la zone d'étude
In the face of increasing concerns about sustainability of agricultural production, cropping systemsare evolving towards systems that fulfill multiple agronomic and environmental objectives. Researchin cropping systems design (CSD) is concerned with studying the effect of farming practices oncropping systems and their performance. The interaction between production and ecosystemservices, and quantification of trade-offs between the two, is a key aspect of this research. A varietyof approaches have been theorized, such as use of models and mobilization of expert knowledge.Models allows fast and low-cost testing of the effect of farming practices under a variety ofconditions, but the application of theoretical outcomes to on-farm changes can be limited by localconstraints and researcher-farmer communication. Mobilizing farmers and other relevantstakeholders for CSD can help overcome these obstacles; however this limits innovation to the scopeof expert knowledge.The objective of this thesis is to combine modeling and participatory methods for a CSD frameworkthat harnesses the potential of numerical modeling while ensuring the proposed solutions take intoaccount socioeconomic and environmental constraints. After an overview of current advances inprototyping and CSD, we propose an methodological framework divided into four parts; a) combininga typology of farming practices and a conceptual model to appraise the diversity of farming practices,constraints and trade-offs at the plot scale in a defined production area; b) collection of field data forquantifying relevant trade-offs between production and ecosystem services; c) selecting andpreparing an appropriate numerical model for simulating the effects of farming practices onproduction and provision of ecosystem services; and d) evaluating whether the interaction of farmerswith a numerical model can generate candidate cropping systems that fulfill our agro-environmentalobjectives (provision of ecosystem service) as well as being suitable for the farmers who will adaptthem for on-farm experimentation.The coffee-based agroforestry systems (coffee/shade trees) of central Costa Rica were the chosenproduction system for answering these questions. Agroforestry systems offer plentiful opportunitiesfor valuing ecosystem services in addition to crop production; the combination of two perennialcrops brings long-term performance assessment and sustainability of the system to the heart of thequestion. Coffee cultivation in central Costa Rica concerns a large amount of livelihoods, but is alsobased on intensive management of a highly valued cash crop vulnerable to price fluctuations on theglobal market as well as climate change. Steep slopes and heavy rainfall also cause high levels of soilerosion; yet certain indirect erosion control practices (such as the use of shade trees of weeds) alsohave an impact on coffee production. The reconciliation of these two aspects offers the opportunityto test our methodological framework in situations where precise discussions onproduction/environment trade-offs are needed.Finally, in the last chapter we reflect on the importance of correctly choosing and preparing the rightmodel for the job, potential application of this methodology, as well as the recommendations wereable to make in terms of erosion control practices in the study area

碩士
國立臺灣大學
農藝學研究所
104
Food security is an important issue for all countries around the world, especially when food production has been challenged under climate change. The food self-sufficiency ratio of Taiwan is around only 33 % weighted by energy in 2013, with importing excessive cereal grains as a serious threat to Taiwan. Also, there is about 10 % artificially greenhouse gas emission generating from agriculture production. Therefore, it is suggested to mitigate the environmental impacts from agriculture production system and increase the degree of food self-sufficiency ratio of Taiwan. Rice-wheat rotation is a possible innovative cropping system for Taiwan, which integrate with the upland-lowland rotation, wheat production and labor saving. In the present study the analysis of environmental impacts of rice-wheat rotation system was performed by the tool of life cycle assessment and hot spots of the impacts for the cropping system were determined. This study is aim to establish a local climate-smart cropping system which is high yield, high quality, energy saving, food production and eco-friendly. In the study, a two-year rice-wheat rotation experiments at TDARES (Taichung District Agriculture Research and Extension Station) and Daya (Taichung) since 2012 winter was conducted. The system boundary of life cycle assessment consisted of production of farm inputs (such as fertilizer, pesticide and seed), tillage, irrigation, farming practice and post-harvesting, and used the function unit as kg grain and per hectare in evaluating the environment impacts from crop production. In this study we selected energy consumption, global warming potential, acidification, and eutrophication as environmental impact items to evaluate rice-wheat system. According to the research results, the main environment impact came from field emission and the variation was up to 50 %. In each crop, the GWP (Global warming potential) was 3~53 tg CO2 eq /ha and 1.3~10 kg CO2 eq/ kg grain. Although field emission was the main hot-spot, it still could be improved by modified fertilizer management. In this study, fertilizer adjustment was the most effective way to mitigate the field emission, while other adjusted strategies such as tillage and second crop period fallow didn’t show consistent mitigation effects. But there is still some positive effect of non-tillage and changing crop residue retention ratio has been confirmed in several long-term field research. In all, minimum tillage and suitable fertilizer management seemed to be the suitable practice for establishing climate-smart rice-wheat rotation system.

碩士
國立中興大學
農藝學研究所
82
Traditionally two rice crops per year was very popular on paddy fields in Taiwan. it is widely recognized that living standards in Taiwan had been greatly improved as a result of rapid economic growth in the past years. Decreasing in rice consumption has contributed to rice over-production wihic exerts a critical impact in the agricultural economy. Therefore. the paddy field diversion plan which was first introduced by the government in 1983, aimed to reduce the production of rice. This study attempted to determine the rice productivity of paddy fieleds on which various cropping systems had been adopted for severn years. An one year field experiment was conducted in the Hualien District Agricultural lmprovement Station The cropping systems preceded this experiment included (A) rice-rice, (B) peanut-rice, (C) rice-soybean and (D) corn-soybean, from 1986 to 1992 To investigate the effect of soil property on the growth and yield of rice cultivar TK6, randomized complete block design was laid out with three replications. Major agronomic traits, yield and yield components were measured; soil analysis and weed investigation were taken. 　　Experimental results showed that cropping patterns could change soil property or weed incidence after the paddy field diversion Re-cropping two seasons of rice in different cropping pattern, the productivity was.influenced by various cropping systems. A positive effect of rotation on rice yield was observed in both cropping systems compared with continuous rice. Field was free from broad leaf weeds, but more narrow leaf weeds were observed as the continuous rice. Soil available K2O and Cu increased while re-cropping first crop of rice. When second crop of rice, soil organic matter, available P2O5, MgO, Mn and Zn increased except that CaO decreased. Results suggest that the increased rice yield associated with rotation may have been due to a general improvement in soii property and plant nutrition.

In Lombok (Indonesia), annual cropping patterns in irrigated areas are divided into three cropping cycles of four months each. In better irrigation schemes, there are normally two irrigated flooded-rice crops, i.e. wet season and dry season lowland rice crops in sequence, followed by one non-rice crop cycle during the driest months (this is referred to as the twice-rice system). In less developed irrigation schemes, one lowland rice crop is normally grown during the rainy season, followed during the driest months by two cycles of non-rice crops, or a non-rice crop and a fallow (this is referred to as the once-rice system). In rainfed areas, especially in the vertisol soil areas, there are upland rice systems in the highland or hillsides, and “Gora” (dry seeded-flooded) rice systems in the lowland. In this area, rice is grown only once a year during the rainy season of the monsoon. Farmers in Lombok do not normally fertilise the non-rice crops such as soybean and mungbean grown following rice, and application rates of fertiliser to rice have fallen since the economic crisis in 1998. Therefore phosphorus (P) deficiency may be expected, which may explain the very low yields of soybean and mungbean achieved by farmers in Lombok. With low P, arbuscular mycorrhizas (AM) might be expected to play an important role in plant nutrition, but inoculation with arbuscular mycorrhizal fungi (AMF) increased root colonisation and yield of these crops in a recent field experiment in Lombok. There had been no survey of AMF populations in rice-based systems in Lombok prior to the work reported here, and little such work anywhere internationally. Therefore, an extensive survey was conducted in Lombok on the two main soil types with rice-based systems. Another field survey was conducted in the Riverina rice-growing area (Australia), as a comparative study to the Lombok survey. In Lombok, rice systems with longer total annual flooding duration had lower populations compared with upland or Gora rice systems. It was therefore suggested that the lower colonisation level in flooded rice was due to the flooded conditions, as well as soil chemical properties associated with flooded conditions, rather than the rice plant itself. There are options for improving AMF population for better growth of non-rice rotation crops, or even for rice crop in Lombok as fertilisers become less affordable and their use on flooded rice is declining. The easiest option is to inoculate AM fungi in the nursery or to make nursery beds in a paddock previously cropped with AMF-stimulating species, such as soybean, to start infection on rice seedlings, which should be better with a dry nursery. The second option is to modify the technique of growing rice, such as applying the SRI (System of Rice Intensification) principles, in which rice is grown without flooded conditions but intermittent short flooded and upland conditions. This will keep the soil in an aerobic condition much of the time and should facilitate the development of beneficial microbial populations and activities in the soil, such as AMF and nitrogen fixers. The SRI method has been reported to increase rice yield dramatically, even in soil with low fertility levels.
Doctor of Philosophy (PhD)

In Lombok (Indonesia), annual cropping patterns in irrigated areas are divided into three cropping cycles of four months each. In better irrigation schemes, there are normally two irrigated flooded-rice crops, i.e. wet season and dry season lowland rice crops in sequence, followed by one non-rice crop cycle during the driest months (this is referred to as the twice-rice system). In less developed irrigation schemes, one lowland rice crop is normally grown during the rainy season, followed during the driest months by two cycles of non-rice crops, or a non-rice crop and a fallow (this is referred to as the once-rice system). In rainfed areas, especially in the vertisol soil areas, there are upland rice systems in the highland or hillsides, and “Gora” (dry seeded-flooded) rice systems in the lowland. In this area, rice is grown only once a year during the rainy season of the monsoon. Farmers in Lombok do not normally fertilise the non-rice crops such as soybean and mungbean grown following rice, and application rates of fertiliser to rice have fallen since the economic crisis in 1998. Therefore phosphorus (P) deficiency may be expected, which may explain the very low yields of soybean and mungbean achieved by farmers in Lombok. With low P, arbuscular mycorrhizas (AM) might be expected to play an important role in plant nutrition, but inoculation with arbuscular mycorrhizal fungi (AMF) increased root colonisation and yield of these crops in a recent field experiment in Lombok. There had been no survey of AMF populations in rice-based systems in Lombok prior to the work reported here, and little such work anywhere internationally. Therefore, an extensive survey was conducted in Lombok on the two main soil types with rice-based systems. Another field survey was conducted in the Riverina rice-growing area (Australia), as a comparative study to the Lombok survey. In Lombok, rice systems with longer total annual flooding duration had lower populations compared with upland or Gora rice systems. It was therefore suggested that the lower colonisation level in flooded rice was due to the flooded conditions, as well as soil chemical properties associated with flooded conditions, rather than the rice plant itself. There are options for improving AMF population for better growth of non-rice rotation crops, or even for rice crop in Lombok as fertilisers become less affordable and their use on flooded rice is declining. The easiest option is to inoculate AM fungi in the nursery or to make nursery beds in a paddock previously cropped with AMF-stimulating species, such as soybean, to start infection on rice seedlings, which should be better with a dry nursery. The second option is to modify the technique of growing rice, such as applying the SRI (System of Rice Intensification) principles, in which rice is grown without flooded conditions but intermittent short flooded and upland conditions. This will keep the soil in an aerobic condition much of the time and should facilitate the development of beneficial microbial populations and activities in the soil, such as AMF and nitrogen fixers. The SRI method has been reported to increase rice yield dramatically, even in soil with low fertility levels.