Farmers’ perceptions and management of risk in rice/shrimp farming systems in South-West Coastal Bangladesh

Farmers in Bangladesh face considerable risk due to fluctuations in biophysical and economic conditions, but the response to these risks is poorly understood. In particular, there is a need to better understand the endogenous management of risk in the rice/shrimp farming systems that have emerged in the inner coastal zone of Bangladesh. This paper draws on a case study of a typical rice/shrimp farming village in Khulna District to explore: (a) farmers’ perceptions of risks and their management responses, (b) risk-return trade-offs within small-, medium-, and large-farm households, and (c) the role of other farm and non-farm activities in mitigating risks to household livelihoods. Farm-level data were collected through a reconnaissance survey, a village census, household case studies, and a sample survey of 73 households. Representative farm budgets were constructed for the three farm-size classes. The key performance indicators calculated were gross margin (GM), net income (NI), and GM per workday of family labour. The riskiness of the rice/shrimp system was assessed for each farm type using farmers’ estimates of low, normal, and high yields and prices to specify triangular distributions. Cumulative distribution functions (CDFs) for GM, NI, and GM per workday were generated. A whole-farm economic analysis was also conducted to assess the relative contributions of different sources of income for each farm type. With access to saline water for shrimp farming in the dry season and fresh water for rice in the wet season, farmers have developed and progressively adapted an alternating rice/shrimp farming system that has minimised the trade-offs between the two crops and provides a good return to household and village resources for all farm types. The system is subject to significant production and market risks, especially the shrimp component. However, farmers have clearly perceived these risks and ameliorated them through a range of production, marketing, and management strategies. With these risk management practices, the rice/shrimp cropping system is economically viable, given the current variation in yields and prices. The greater risk associated with the shrimp component was offset by the renewed stability of the rice component over the past decade, and the risks of the whole cropping system were offset by other farm and non-farm sources of livelihood. Development interventions need to work with farmers to provide further options (suitable rice varieties, solutions to shrimp disease, improved village and transport infrastructure) if this resilience is to be maintained.     

Managing tropical wetlands for advancing global rice production: Implications for land-use management

Being fertile lands, wetlands have been managed for traditional agriculture over millennia. However, the integrity and ecosystem services of wetlands are being jeopardized by intensive land-use comprising of drainage and excessive disturbance. An adhoc and intensive use of wetlands, without preserving ecological integrity is causing ecosystem disservices and threatening conversion of a large soil organic carbon (SOC) sink into a net source. Wetlands in the tropical parts of the world are distributed unevenly and represent ∼3% of the total world land area. Due to stagnancy and even reduction in rice (Oryza sativa) yield of many agricultural regions, there is a need for additional and alternative land-uses which can raise the global rice production to ∼1 billion Mg (megagram = 10⁶g = metric ton) by 2050 from ∼497 million Mg now. Wetlands can be a viable option to advance global food security because of high soil fertility and vast geographical distribution. A ‘3-tier rice production system’ is proposed herein based on specific hydrological niche to advance global food security without degrading the ecosystem services of wetlands. In addition to increasing agronomic yield, the proposed modus operandi can also improve the livelihood security of farmers through an additional income streams by: (i) trading of SOC credits generated through adoption of conservation agriculture in littoral zones, and (ii) promoting fish and duckery culture in conjunction with deepwater rice farming. Furthermore, the proposed strategies will also set in motion the process of restoration of wetlands while enhancing C sink capacity of the ecosystems.     

水产养殖与植被恢复对红树林湿地土壤的影响

通过对原生红树林、养殖虾塘和鸭塘、废弃虾塘表层土壤中全氮、全磷、全钾、土壤微生物总DNA以及土壤有机碳指标测定,得到养殖对红树林湿地土壤的影响以及红树林恢复对废弃虾塘土壤的修复作用。结果显示：原生红树林中的全氮和土壤有机碳含量较高;废弃虾塘A的全氮和废弃虾塘B的土壤有机碳最低;全磷含量在鸭塘最高,在废弃虾塘B最低;全钾在废弃虾塘A中的含量较其他4个样地高,最低值为鸭塘;土壤表层微生物总DNA浓度为鸭塘最高,废弃虾塘A最低;土壤C/N随着土壤微生物总DNA的升高而降低。植被恢复后,废弃虾塘土壤中土壤有机碳、全氮升高,全钾逐渐下降,而全磷变化较大,且这4个指标总体逐渐接近原生红树林中相应指标值。说明废弃虾塘植被恢复后,土壤性质逐步接近原生红树林土壤,红树林对废弃虾塘土壤有修复功能。     

Examining multi-functionality for crop yield and ecosystem services in five systems of agroecological intensification

Agroecological intensification (AEI) integrates ecological principles and biodiversity management into farming systems with the aims of increasing farm productivity, reducing dependency on external inputs, and sustaining or enhancing ecosystem services. This review develops an analytic framework to characterize the fulfilment of these objectives by documenting the co-occurrence of positive, neutral, and negative outcomes for crop yield and nine regulating ecosystem services. We provide an illustrative examination of the framework, evaluating evidence for yield and ecosystem service outcomes across five AEI systems: conservation agriculture, holistic grazing management, organic agriculture, precision agriculture, and system of rice intensification (SRI). We reviewed 104 studies containing 245 individual comparisons between AEI and contrasting farming systems. In three of the five AEI systems, conservation agriculture, precision agriculture, and SRI, more than half of reviewed comparisons reported ‘win-win’ outcomes, enhancement of both yield and ecosystem services, or ‘win-neutral’ outcomes relative to contrasting farming systems. The review presents substantial evidence that the five AEI systems can contribute to multi-functional agriculture by increasing ecosystem service provision, or reducing negative externalities associated with agriculture, while maintaining or increasing yields. A framework such as the one presented here can help guide decision-makers considering how best to implement multi-functional agriculture so that both crop yield and ecosystem service delivery can be maintained or increased.     

辽宁中部稻区水田合理耕层构建技术规程

辽宁中部稻区主要包括沈阳市、辽阳市等地,属于北方一季粳稻区,气候适宜,温光条件好,土地平坦,稻田土层深厚,有机质、氮、磷、钾等较为丰富,非常适合水稻生产。但是,由于耕作水平不高、灌溉技术水平较低,且长期单一地使用化肥进行掠夺式生产,导致地力下降、土壤结构不良、耕性变差、耕层变浅、养分失衡、保水保肥和抗旱减灾能力下降,严重影响了水稻生产。为了很好地解决这些问题,辽宁省水稻研究所开展了针对性的研究,制定了辽宁中部稻区水田合理耕层构建技术规程,从机械耕整地、施肥管理、水分管理、秸秆还田四个方面,提出了辽宁中部棕壤型稻区水田合理耕层构建的技术措施,以期能够促进辽宁水稻可持续发展,实现水稻高产稳产。     

水足迹视角下京津冀县域粮食作物水土资源匹配格局

[目的]农业水土资源是粮食生产的决定因素,探明京津冀粮食生产中水土资源匹配格局特征对区域经济发展有深远的影响。[方法]文章从水足迹的视角出发,分析了1980—2018年京津冀县域5种主要粮食作物（小麦、玉米、稻谷、大豆、薯类）的产量、播种面积、水足迹、耕地面积的时空变化,运用水土匹配系数法及ArcGIS深入研究了1983年、1998年、2003年和2016年水土资源匹配格局,并进一步剖析区域农业水土匹配对农业生产的影响。[结果]（1）当前京津冀水土匹配系数区间为[0.02,1.25],超出区间范围[0.281, 0.431];粮食生产格局与水土匹配系数空间格局均为“冀中南高、北部低”。（2）研究时段内,京津冀粮食总产量提高1.14倍,播种总面积降低19.28%,粮食单产量显著提高;灌溉提高粮食单产量,水土匹配系数与粮食单产量呈正相关。（3） 1980—2019年京津冀5种作物蓝水足迹均值（136.64亿m3）是绿水足迹均值（99.60亿m3）的1.37倍,各作物水足迹变化不同,间接反映地区农业种植结构的改变。（4）京津冀水足迹总量提高2.45倍,耕地总量下降20.59%,水土匹配系数变...     

Factors Affecting Technical Efficiency of Rice Farmers in Village Reservoir Irrigation Systems of Sri Lanka

Given the importance of water for rice production, this study examines the factors affecting the technical efficiency (TE) of irrigated rice farmers in village irrigation systems (VIS) in Sri Lanka. Primary data were collected from 460 rice farmers in the Kurunagala District, Sri Lanka, to estimate a stochastic translog production frontier for rice production. The mean TE of rice farming in village irrigation was found to be 0.72, although 63% of rice farmers exceeded this average. The most influential factors of TE are membership of Farmer Organisations (FOs) and the participatory rate in collective actions organised by FOs. The results suggest that enhancement of co‐operative arrangements of farmers by strengthening the membership of FOs is considered important for increasing TE in rice farming in VIS.     

Land-Use Sustainability of Composite Swiddening in the Uplands of Northern Vietnam: Nutrient Balances of Swidden Fields during the Cropping Period and Changes of Soil Nutrients over the Swidden Cycle

This study examined the sustainability of the swidden component of the composite swiddening system practiced by the Tay ethnic minority in Tat hamlet, Hoa Binh province in Northern Vietnam. This farming system is thought to be suitable for the uplands where land degradation is a serious problem. The common swidden rotation of two years of rice, two years of cassava and five years of bush-tall grass fallow was evaluated for the extent of land degradation during the cropping period by nutrient balance analysis, and for soil nutrient status throughout the swidden cycle through soil analysis. Four fields representing the individual years of cropping and three fields representing the first, the third and the fifth years of bush-tall grass fallow were selected for field measurements. Nutrient balance analysis indicated substantial losses of all major nutrients, particularly K, in all cropping years. Soil analysis also showed a decline in soil fertility during the cropping period and a partial restoration of soil fertility during the fallow period. However, only five years of bush-tall grass fallow was not sufficient to restore the original level of soil fertility. Thus, swidden fields in Tat hamlet are degrading, posing a serious threat to their land-use sustainability.     

“一带一路”背景下新疆农业水土资源配置研究

[目的]新疆作为"一带一路"发展战略的核心区,为新疆地区经济的发展带来了新的机遇。但如何提高农产品在国际市场上的竞争力,如何处理全区的水土等资源的合理配置是目前新疆地区面临的首要问题。[方法]文章以新疆农产品对中亚5国比较优势为背景,以2015年全区的农业投入产出情况作为基础数据,采用线性规划模型,借助Matlab软件进行求解,对新疆地区的水土资源进行有效分配,以全区的农业结构优化方案作为表现形式。[结果]新疆地区应减少小麦、玉米、棉花等效益较低、耗水较高、用工较多的作物种植面积,增加大豆、马铃薯等可套种、可抗旱且收益较高的作物种植面积,增大葵花、蔬菜、果用瓜、苜蓿等经济作物种植面积。同时,该地区应扩大畜牧业的养殖数量,并增加饲草的来源。[结论]基于"一带一路"倡议,新疆需充分利用地缘优势,以经济效益最大化为发展目标,对全区农业结构进行优化调整,以达到水、土等资源的合理配置,最终推动新疆地区与中亚5国的农产品贸易良好发展。     

The effects of repeated soil wetting and drying on lowland rice yield with system of Rice Intensification (SRI) methods

In lowland rice farming, water management is the most important practice that determines the productivity of other inputs, e.g. nutrients, herbicides, pesticides, farm machinery, microbial activity, mineralization rates. Deliberate flooding or poor drainage that keeps soil saturated is detrimental to crops and degrades soil quality. This study evaluated whether rice grain yield could be increased relative to continuous flooding by using the management practices of the System of Rice Intensification (SRI). The effects of SRI's repeated wetting and drying cycles plus different plant populations were investigated at Sapu Research Station in The Gambia, on an alluvial soil between 2000 and 2002. The water management practices proposed for SRI were found to be beneficial to rice growth. At 20 cm spacing, average grain yield with SRI practice was 7.3 t ha^?1 compared with 2.5 t ha^?1 under continuous flooding. At 30 cm spacing SRI practice yielded 6.6 t ha^?1, while under continuous flooding, grain yield was only 1.7 t ha^?1. Even wider spacing did not produce higher yield. At 40 cm spacing, SRI management gave 4.7 t ha^?1, while continuous flooding yielded 1.3 t ha^?1. Thus overall, SRI practices gave better results than continuous flooding. This was probably as a result of increased nutrient availability and superior growing conditions which enhanced physiological development and grain yield. Rewetting dry soil reportedly facilitates nitrogen mineralization. The phenomenon of having a flush of nitrogen mineralization occurring after rewetting dry soil was first reported by Birch in 1958. This intensive pathway of nitrogen mineralization and nitrogen availability has potential to increase lowland rice yields in ways consistent with sustainable agricultural production.     

Resisting Environmental Dispossession in Ecuador: Whom Does the Political Category of ‘Ancestral Peoples of the Mangrove Ecosystem’ Include and Aim to Empower?

The development of shrimp aquaculture in Ecuador caused massive ecological damage, particularly in the mangrove areas. Consequently, the livelihood of the population linked to this ecosystem was disrupted. Faced with environmental dispossession, the population engaged in the defence of mangroves by articulating a national grassroots movement. In 2007, this movement implemented a novel identity politics strategy that linked mangrove ecosystem to indigeneity, and positioned itself as the ‘Ancestral Peoples of the Mangrove Ecosystem’ (PAEM). This paper focuses on the political economy of the shrimp‐farming industry in Ecuador, showing the interrelation between environmental dispossession, collective action and identity formation, and analysing how this novel political identity is understood by different members of this social movement. The work argues that PAEM refers to a category that is closely linked to the processes of mangrove defence, in direct opposition to the shrimp farmer's identity, rather than to an essentialized conception of identity based on ‘nativeness’.     

Evaluating the economic impacts of crop yield change and sea level rise induced by climate change on Taiwan's agricultural sector

This article investigates the effects of sea level rise and climate change induced crop yield alterations on Taiwan as well as possible adaptation strategies. For sea level rise of up to 5 meters, as much as 4.9% of total acreage and 16% of rice acreage would be lost. The empirical findings show that the sea level damages range from NT$ 0.84 to 4.10 billion while crop yield losses range from NT$ 1.79 to 2.55 billion. We investigate alternative adaptation strategies finding crop yield technological progress and tariff reduction could significantly mitigate these effects.     

政府培训、技术认知与农户生态农业技术采纳行为以稻虾共养技术为例

[目的]农户作为生态农业技术最直接的采纳者,其对生态农业技术有着独立的选择权,农户是否采纳生态农业技术直接影响到该技术的推广效率。稻虾共养技术实现了水稻种植和小龙虾养殖相协调,该技术符合生态农业技术的要求。因此,文章以稻虾共养技术为例,通过分析江苏省和湖北省稻虾共养技术推广情况,以期提高农户对稻虾共养技术的采纳行为,并重点从政府培训、农户技术认知、农户个体特征、家庭经营特征和社会网络等五方面研究其对农户采纳稻虾共养技术的影响。[方法]运用二元Logistic模型和Bootstrap方法,基于江苏省和湖北省共612份农户的微观调研数据,实证分析了政府培训、技术认知对农户稻虾共养技术采纳行为的影响及其内在作用机制。[结果](1)政府培训次数和政府培训有效性对农户稻虾共养技术采纳行为有显著的正向影响,政府培训及时性对农户稻虾共养技术采纳行为的影响效果不显著;(2)其内在作用机制主要体现在,政府培训有效性可以提高农户技术认知水平,降低其技术应用风险,最终促使农户产生技术采纳行为;(3)户主是否村干部、是否加入合作社等对农户采纳稻虾共养技术有显著的正向影响,而户主年龄和耕地块数对其技术采纳行为有显著的负向影响。[结论]政府培训能够提高农户对生态农业技术的采纳行为,并且政府通过技术培训,可以提高农户对生态农业技术的认知,进而对农户技术采纳行为产生显著的正向影响。     

Effects of intercropping rice and water spinach on net yields and pest control: an experiment in southern China

Strategies encouraging the use of fewer agrochemicals while maintaining high yield are highly demanded for smallholder rice farmers. Intercropping helps to suppress pests and disease in upland farming systems. However, information on the role of intercropping in pest suppression and crop productivity in irrigated rice farming systems is sparse. To explore the possibility of establishing diversified agriculture management strategy that requires lower agrochemical inputs, a field study was conducted to evaluate the effect of rice and water spinach intercropping on the occurrence of pests, disease, and land-use efficiency. Results demonstrated that the occurrence of rice blast disease, sheath blight disease, and Cnaphalocrocis medinalis was substantially lower than pure stands. Compared with rice monoculture, the tiller number, net photosynthetic rate, and leaf chlorophyll content were significantly increased in rice at the edge rows adjacent to water spinach in intercropping. Intercropping increased the per unit area yield of rice without significant reduction in that of water spinach. Land equivalent ratio (LER) was 1.13, showing that intercropping was 13% more productive than rice monocropping. Net income for intercropping was 5.04 times higher than for rice monocropping. These findings suggest that rice and water spinach intercropping is a viable alternative for sustainable rice production with a small farming scale in southern China.     

Assessing effects of federal crop insurance supply on acreage and yield of specialty crops

Crop insurance may affect harvested acreage and yield by influencing producers’ behavior such as land allocation and input use. Although specialty crops are a major source of farm income, especially on the U.S. west coast, they have not received as much attention as field crops in previous empirical studies. This paper assesses the effect of moral hazard and adverse selection associated with the federal crop insurance program (FCIP) on the acreage and yield of major specialty crops in California. An econometric method that expands the switching regression model is developed to assess the effect. Results suggest that federal crop insurance can change specialty crop growers’ production responses to climate and soil conditions. The moral hazard effect tends to increase the acreage and yield of the specialty crops, whereas the adverse selection effect tends to have the opposite effect. The overall effect of the FCIP on acreage and yield of specialty crops is found to be moderate.     

Explaining the Diversity of Southeast Asian Shrimp Aquaculture

Despite the large amount of academic attention that Southeast Asian shrimp farming has received since the 1980s, few attempts have been made to explain the remarkable variation in the industry's organization across countries and localities. This paper compares the development of shrimp farming in Indonesia, the Philippines and Thailand, arguing that differences can be traced to variations in the initial conditions under which shrimp farming was established, the different ways that national aquacultures are embedded in the regional political economy and the ways in which different countries have responded to the characteristic environmental problems the sector causes itself.     

稻鳅共生种养模式试验研究

[目的]稻鳅共生是典型的稻田综合利用模式,符合生态农业发展方向。通过对稻鳅共生生态系统的生理生态学机制开展试验研究,为进一步推广稻鳅共生种养模式提供科学依据。[方法]采用田间试验方法,以水稻单作为对照,研究了不同泥鳅养殖密度下的稻鳅共生对水稻农艺性状、土壤理化性质、水稻产量构成的影响,并对稻鳅共生种养模式进行了经济效益分析。[结果]与对照处理相比,水稻长势在株高、有效分蘖率、根长等方面有一定提高。养殖田水稻株高增高了3%,有效分蘖率提高了8%~11%,根长提高了8.8%~31.3%。在土壤理化性质方面,与对照相比,土壤容重降低了7.1%~21.2%,孔隙度增加了4.1%~14.7%。实验前后养殖田内土壤有机质增加了3.5%~26.5%,对照田降低了2.5%~5.8%。土壤肥力(氮、磷、钾)减少,但减少幅度小于对照处理。稻鳅共生种养模式下水稻产量提高了5%~25%,同时稻田增收泥鳅1 725~3 375kg/hm2,净收入为1.836 0万~2.307 0万元/hm2,经济效益提高了3.65~4.84倍。稻鳅共生种养模式中泥鳅的养殖密度为30万尾/hm2时稻田的生态效益和经济效益最佳。[结论]稻鳅共生有效改善了土壤理化性质,促进了水稻的生长,提高了稻田产量和产值。     

A study of farmer’s decision and incentive scheme to reduce highland maize farming in Thailand

During the past 15 years, there has been a considerable increase in highland maize farming in Nan, a province in northern Thailand. The increase in farming area causes an excessive forest encroachment and environmental problems, e.g. soil degradation, landslide, and pesticide contamination. This research explores the mechanism and factors which drive a sustainable transformation from highland maize farming to reforestation. We survey 107 farmers in Nammeed and Sopsai watersheds in where the reverses of growing trend of deforestation in Thailand have been observed. Comparative statistical analysis and regression are used to analyse factors affecting farmer’s decisions and compare differences between the two sites. We find that the fundamental mechanism driving a sustainable transformation from highland maize farming to reforestation comprises 3 pillars. These are 1) realization of adequate economic, health or environmental benefits derived from the alternatives; 2) a sense of belonging and attachment towards the forest and 3) effective enforcements of communal rules and regulations. While natural transformation in Nammeed area highlights the roles of flatland as key driver of the change, subsidy schemes can supplement the transformation during transitional period as seen in Sopsai area.     

Socioeconomic aspects of rice‐fish farming in Bangladesh: opportunities,challenges and production efficiency*

In spite of the potential for rice‐fish farming in Bangladesh, it has been adopted by relatively few farmers because of socioeconomic, environmental, technological and institutional constraints. Rice monoculture remains the main farming system in Bangladesh even though integrated rice‐fish farming is the best farming system in terms of resource utilisation, diversity, productivity, production efficiency and food supply. Only a small number of farmers involve in integrated rice‐fish farming. This study concludes that rice‐fish farming is as production efficient as rice monoculture and that integrated performs better in terms of cost and technical efficiency compared with alternate rice‐fish farming. Integrated rice‐fish farming can help Bangladesh keep pace with the current demand for food through rice and fish production. However, a lack of technical knowledge of farmers, high production costs and risks associated with flood and drought are inhibiting more widespread adoption of the practice.     

An institutional and policy framework to foster integrated rice–duck farming in Asian developing countries

Asia has accounted for the vast majority of the world's rice and meat-duck production. In the integrated rice–duck farming (IRDF) system, ducklings are released into rice paddies in order to maximize the use of renewable resources in a closed-cycle flow of nutrients during rice vegetation periods. Rice–duck farming used to be widely adopted in tropical and subtropical eastern Asian countries, but has remained unpopular in the wake of prevailing agricultural productivism characterized by specialization, intensification, mechanization and excessive dependence on agrochemicals. This paper sets out institutional pathways that can redevelop IRDF in Asia. These include organic food certification systems, organic farmers' cooperatives, community-wide organic farming, localized technical extension and educational services, and between-farm rice–duck integration. A comprehensive package of these institutional tools would further expedite the expansion of IRDF particularly in low-income Southeast Asia where the rice or duck farming landscape is overwhelmingly dominated by smallholders.