Effects of food consumption patterns on paddy field use in Taiwan

Societal metabolism and land use are significant and interrelated issues, and play a role in sustainable development. How a society's metabolism relates to local land use is typically affected by the particular context of the society under study, which is usually shaped by many factors, including economic, ecological, cultural, technological, and political factors. This study examines the effects of changes in food consumption patterns – decreasing per capita consumption of rice and increasing per capita consumption of wheat flour and meat – on the use of paddy fields in Taiwan. Although rice is grown domestically, wheat, which is a substitute for rice, is mainly imported. Moreover, the domestic livestock industry depends heavily on imported crops for low-cost feed. Accordingly, dietary changes have significantly decreased the demand for local paddy fields to grow crops. Additionally, the diversion of paddy fields to grow forage crops, which has been promoted by the Taiwanese government by guaranteeing prices for feed maize for 14 years, was discouraged when Taiwan joined the World Trade Organization in 2002, as Taiwan was required at that time to reduce by 20% its aggregate measure of support. The presented Taiwan case provides an empirical example of how a change in input characteristics (supply sources in a spatial dimension) of societal metabolism can, together with other factors, significantly affect local paddy fields, and discusses the underlying implications for sustainable development.     

我国农作物秸秆综合利用现状及焚烧碳排放估算

[目的]为加快推进秸秆资源化利用工作,有效缓解因秸秆焚烧带来的环境问题。[方法]将全国划分为黄淮海区、西北区、东北区、东南区、西南区五大区域,对各类农作物秸秆进行了统计分析,研究了秸秆产生量、秸秆资源密度、秸秆利用结构、秸秆焚烧碳排放量。[结果]全国秸秆理论资源量达到10.4亿t,可收集量达到9.0亿t,玉米、水稻和小麦3类农作物秸秆占总量的79.19%,黄淮海区秸秆产量最高,占总量的33.41%。秸秆已利用量为7.21亿t,综合利用率达到80.11%,其中肥料化、饲料化、基料化、燃料化、原料化利用量占已利用量的比例分别为53.93%、23.42%、4.98%、14.27%、3.40%,形成了农用为主的利用格局,但不同秸秆种类综合利用率和利用结构存在显著差异。全国秸秆资源密度和人均占有量分别为523.57kg/667m~2和1.75 t,东北区显著高于全国平均水平,西南区和东南区则显著低于全国平均水平。根据环保部卫星遥感监测的露天焚烧火点数比例估算,2015年我国秸秆露天焚烧量约为8 110万t,总碳排放量约为3 450万t,其中东北地区约占74.1%。[结论]我国秸秆综合利用的重点和难点在东北地区,进一步推动区域秸秆实现全量利用,对于促进低碳农业发展,应对气候变化有着十分重要的意义。     

Balancing productivity and trade objectives in a competing environment: should India commercialize GM rice with or without China?

India is considering approving genetically modified (GM) rice, but it fears losing rice exports to sensitive countries with import regulations on GM food, and may wait for China to lead the way. Using a multiregion, computable general equilibrium (CGE) model, we simulate the economic effects of introducing GM rice in India with or without China in the presence of labeling and import approval regulations of GM food in GM sensitive importing countries. We find that the welfare gains with GM rice in India would largely exceed any potential export loss, and that the segregation of non-GM rice could help reduce these minor losses. We also find no significant first mover advantage for India or China on GM rice. The opportunity cost of segregation of non-GM rice is much larger for sensitive importers than for India, which suggests that these importers would have the incentive to pay for the cost of segregation.     

Impact of training on the intensification of rice farming: evidence from rainfed areas in Tanzania

Agricultural development is indispensable for poverty reduction and food security in sub‐Saharan Africa (SSA). This study investigates the impact of rice production training in a modified version of the System of Rice Intensification (SRI) on the performance of small‐scale rice farmers in a rainfed area of Tanzania. Utilizing the plot level variation, we employ propensity score matching (PSM) to assess the impact of training on technology adoption, productivity, and profitability. We also estimate a difference‐in‐differences model with plot fixed effects using recall panel data covering the periods before and after training. We found that trainees achieved an average paddy yield of 4.7 tons per hectare and rice profit of 191.5 USD per hectare on the plots where new technologies were adopted, which is higher by about 1.3–1.8 tons and 119–137 USD per hectare than on the other plots. Our study suggests the high potential of transforming favorable rainfed rice growing areas in SSA so as to achieve a rice Green Revolution through training in modern input use and improved agronomic practices.     

Carbon dioxide emissions from wood fuels in Sweden 1980–2100

It is often assumed that wood fuels are carbon neutral. This is approximately true in the very long run since the emissions from burning wood fuels are compensated by the uptake from new trees. But it is not true in the short- and the medium term due to a number of factors. This problem is analyzed in detail in this paper, where the net carbon (dioxide) effect of using wood residues in Sweden 1980–2100 is calculated. Two important implications of the program for using wood fuels are considered: (i) the decrease of carbon stored in logging residues due to a faster transformation to carbon dioxide and (ii) delayed growth of new forest generations when logging residues are removed from the forest and used as fuel. The effects of both these factors are calculated (and projected) for the period 1980–2100. The main result is that wood fuels (in the form of wood residues) emits about 60% of the carbon dioxide that would have been emitted if the corresponding amount of energy would, have been produced by oil. One policy implication of this is that emissions from wood fuels should not, as is now the practice, be ignored and by definition equaled to zero, in national and international statistics of green house gas emissions.     

Agriculture-led growth: foodgrains versus export crops in Madagascar

This article compares the growth-generating power of alternative agricultural development strategies in Madagascar. Projections from a semi-input–output model and a recently developed social accounting matrix suggest that both paddy and export crops stimulate strong linkages with other sectors of the Malagasy economy. But since paddy output can be increased at lower cost, investment in rehabilitating small irrigated rice perimeters generates 40% to 100% more gdp than a comparable investment in coffee production. Paddy also generates greater employment and a more equitable income distribution.     

Factors influencing hybrid rice adoption: a Bangladesh case

As rice constitutes the major share in cereal consumption in South and East Asian countries that ranges from as low as 40 per cent in India to 97 per cent in Myanmar, to ensure food security, governments in these countries are encouraging farmers to adopt hybrid rice. This is mainly because hybrid rice provides a yield gain of 15–20 per cent over conventionally bred varieties in general. Yet, despite strenuous government efforts, farmers’ adoption rates have remained low in India, Bangladesh and Vietnam compared with China. Although studies often claim that higher seed costs and inferior grain quality are the major factors limiting hybrid rice adoption, very few studies examine the importance of socio‐economic factors and infrastructure in the adoption of hybrid rice. Using Bangladesh as a case, a comparative analysis has been made on the adoption of hybrid and modern varieties relative to traditional rice varieties and land allocation to these varieties. Econometric results indicate that general land characteristics, loan facilities and general infrastructure, such as roads, irrigation facilities and the availability of government‐approved seed dealers, significantly influence the adoption of hybrid and modern rice varieties and land allocation to these varieties compared with traditional varieties.     

Improving China’s food and environmental security with conservation agriculture†

China has achieved impressive increases in agricultural output in recent decades. Yet, past approaches centred on a growing use of fertilizers, pesticides, fuel and water are not likely to achieve the required 30–50% additional increases in food production by mid-century. We show that efficiencies of production are falling and the costs of environmental harm are increasing. Agricultural innovations that improve natural capital are urgently needed. Conservation agriculture (CA) is now practised on >8?Mha in China and is offering promising prospects of both enhanced yields and environmental services. Our meta-analysis of 60 papers with 395 observations in China shows notable benefits from CA. Mean yield increase was 4.5% or 263?kg?ha^?1 for wheat, 8.3% or 424?kg?ha^?1 for maize, and 1.65% or 250?kg?ha^?1 for rice. In 34 datasets from 22 published papers (experimental duration: 2–17 years), 26 datasets (76.5%) show that CA increased yield and soil organic carbon (mean SOC increase of >3?g.kg^?1 in 0–10?cm soil depth) when compared with traditional tillage. Key priorities for the spread of more sustainable forms of agriculture in China are national policy and financial support, better coordination across agencies, and better extension for farmers.     

Potential and limitation of an organic fertilizer‐based development strategy: evidence from Tamil Nadu,India, from 1993 to 2003

This article explores the potential and limitations for using farmyard manure (FYM) to improve paddy and upland cereals productivity under various soil conditions in Tamil Nadu, India. Using household‐level fixed effects, estimated yield functions from 1993 to 2003 confirm that FYM application directly increases crop productivity in upland cereals, but not in paddy rice. Complementary effects through an increase in the marginal product of inorganic fertilizer is observed for both paddy and upland cereals, especially where inherent soil fertility is low. Farmers’ FYM use is responsive to changes in the price of FYM, but transport costs limit price transmission across space. Dairy sector development thus improves crop productivity, but only in the small area around the animals which limits the spread of FYM‐based development strategy.     

Distributional heterogeneity in climate change impacts and adaptation: Evidence from Indian agriculture

This study estimates the distributional heterogeneity in the effects of climate change on yields of three major cereal crops: rice, maize, and wheat in India using district-level information for the period 1966–2015. We distinguish between the effects of changes in growing season weather from those due to changes in long-term climate trends and the heterogeneity in these effects across the distribution of crop yields by estimating naïve and climate penalty inclusive models using fixed-effect quantile panel models. We observe an absence of adaptation against rising temperatures for rice and wheat. However, we find a statistically significant presence of adaptation for wheat and maize for changes in precipitation, though the magnitude is small. Moreover, we find that the effects are asymmetric, and are larger at the lower tail of productivity distribution and smaller at the upper tail of the distribution. A 1°C increase in temperature lowers rice and wheat productivity by 23% and 9%, respectively at the first quantile, but the damage is only 6% and 5% at the ninth quantile. Heterogeneity in impacts and adaptation estimates over the yield distribution curve and across crops suggests the importance of customizing strategies for adaptation to changing weather and climate conditions across regions, crops, and current productivity levels.     

Mitigation potential and costs for global agricultural greenhouse gas emissions1

Agricultural activities are a substantial contributor to global greenhouse gas (GHG) emissions, accounting for about 58% of the world's anthropogenic non‐carbon dioxide GHG emissions and 14% of all anthropogenic GHG emissions, and agriculture is often viewed as a potential source of relatively low‐cost emissions reductions. We estimate the costs of GHG mitigation for 36 world agricultural regions for the 2000–2020 period, taking into account net GHG reductions, yield effects, livestock productivity effects, commodity prices, labor requirements, and capital costs where appropriate. For croplands and rice cultivation, we use biophysical, process‐based models (DAYCENT and DNDC) to capture the net GHG and yield effects of baseline and mitigation scenarios for different world regions. For the livestock sector, we use information from the literature on key mitigation options and apply the mitigation options to emission baselines compiled by EPA.     

中国农作物碳足迹核算研究概述

[目的]碳足迹核算是对农业温室气体排放的定量评价,开展农作物碳足迹核算理论研究能够为低碳农业建设提供技术支撑。[方法]文章在对我国农资投入变化情况进行简要分析的基础上,从碳足迹概念,碳足迹核算的数据来源、方法,我国农作物碳足迹核算涉及的对象、系统边界以及构成、时空分布特征等方面,系统总结了当前农作物碳足迹核算的研究进展。[结果](1)目前我国已开展碳足迹核算的农作物主要有水稻、玉米、小麦、大豆、油菜、脐橙、苹果、油菜和烟叶等,研究过程中活动水平数据、温室气体排放参数来源和核算包含过程的不尽相同,核算过程有仅针对研究对象生产环节的,也有包含上游环节和生产环节的,部分研究还包括产品加工、运输分销、消费和废弃环节,因此核算结果差异较大。(2)研究表明,肥料尤其是氮肥的施用和灌溉耗电是小麦和玉米生产温室气体排放的主要来源,稻田CH₄排放是水稻最主要的排放源,肥料施用和施肥后田间N₂O排放是棉花、花生、大豆、油菜和水果等的温室气体排放的主要来源。(3)同时,受农资投入、耕作方式和技术手段等影响,农作物的碳足迹是不断变化的。[结论]农作物碳足迹核算研究需...     

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。     

Apparent Gains,Hidden Costs: Examining Adoption Drivers,Yield, and Profitability Outcomes of Rotavator Tillage in Wheat Systems in Nepal

The ‘high speed’ rotavator is used for shallow tillage to create a fine tilth and incorporate crop residues, often with a single tractor pass. Rotavator tillage has spread quickly in many parts of South Asia, despite short-term experimental trials suggesting deteriorating soil quality and crop yield penalties. Evidence of rotavator impacts on farmer fields across soil gradients and time is largely absent. From a farm household survey conducted among wheat farmers in Nepal, we estimate wheat yield and profitability outcomes for rotavator adopters and non-adopters using propensity score matching. We find that rotavator adoption leads to inferior outcomes, despite significant cost savings for land preparation (US$ 11–15 per hectare). With rotavator adoption, farmers lose about 284–309 kg of wheat grain and about US$ 93–101 of profits on average per hectare per season, and these penalties increase with longer-term use of the technology. Adoption of rotavator appears to be driven by the cost and time savings for land preparation. Against this backdrop, new policy and extension efforts are required that discourage rotavator use and favour more sustainable tillage technologies.     

Market integration between surplus and deficit rice markets during global food crisis period

Applying the maximum‐likelihood method of co‐integration, this study analysed spatial market integration between an adjacent rice surplus market (India) and deficit markets (Bangladesh and Nepal). The main focus is on the government policies of these three rice‐producing countries which have been imposed to reduce domestic price volatilities in rice markets during the recent ‘global food crisis’ in 2007–2008. The co‐integration tests find that domestic rice prices of India, Bangladesh and Nepal are integrated both in short‐run and long‐run periods despite the imposition of export restriction policies by India. The reason that prices are transmitted so effectively is most likely to be the widespread informal cross‐border trade through the porous borders among India, Bangladesh and Nepal.     

基于近红外光谱的稻谷、大米、大米粉直链淀粉含量预测

以产自安徽省的99份籼米为研究对象,比较稻谷、大米、大米粉近红外光谱测定直链淀粉的差异,利用TAS全校准技术下稻谷、大米、大米粉3种大米物理形态的近红外光谱测定直链淀粉结果的相关性,建立适用于安徽省所产稻谷中直链淀粉营养成分的定量模型.研究结果表明,稻谷、大米、大米粉测定直链淀粉模型的预测相关系数分别为0.863、0....     

滨海滩涂垦区主要大田作物生产碳足迹研究*——以江苏省盐城市为例

[目的]由于自然要素组合的特殊性,与传统内陆农区相比,滩涂围垦区农业生产特点鲜明。摸清该区大田作物碳足迹,可减少区域碳排放,提升农业生产效率,优化区域资源配置。[方法]采用生命周期评价理论结合IPCC田间温室气体计算方法,建立大田作物碳足迹评估模型,估算滨海滩涂垦区大田作物温室气体排量。[结果](1)滨海滩涂地区大田作物的碳足迹(以CO_2当量)总体在0.63～0.769kg/kg范围内,不同作物的碳足迹由大到小依次为:玉米0.769±0.224kg/kg、水稻0.739±0.241kg/kg、小麦0.636±0.183kg/kg和大麦0.630±0.184kg/kg;(2)氮肥生产和施用环节对该区碳足迹贡献度最大,贡献率分别为26.46%～37.12%和29.06%～51.94%。该地碳足迹数值和结构上呈显著地域化特点,与中国其他地区相比,氮肥施用贡献度大,水田灌溉贡献度大。[结论]降低该地区碳足迹,重点关注施氮和水稻灌溉工程两个方面。采用降低施氮量、提高氮肥利用率、发展节水农业与生态农业等措施,可达到降低碳足迹的目的。     

U.S. Agriculture's Role in a Greenhouse Gas Emission Mitigation World: An Economic Perspective

International agreements are likely to stimulate greenhouse gas mitigation efforts. Agriculture can participate either as a source of emission reductions or as a sink for gas emission storage. Emission trading markets are likely to emerge where agriculture could sell emission offsets. Several agricultural opportunities are available at a cost of $10-25 per ton carbon dioxide. Abatement costs for non-agricultural industries have been estimated to be as much as $200-250 per ton carbon dioxide. In the longer run, agriculture's role may diminish because many agricultural strategies offer only one-time gains and non-agricultural emitters may lower costs through technical change.     

The assessment of the impact of oil palm and rubber plantations on the biotic and abiotic properties of tropical peat swamp soil in Indonesia

Current intensification of agricultural activities in Indonesia has led to increased use of tropical peat swamp forests for agriculture. Ideally, peat swamp ecosystems should not be disturbed as they provide essential services such as soil erosion control, ecosystem stabilization and moderation of climate and energy fluxes as well as reducing carbon emission and conserving biodiversity. In this study, agricultural land from Giam Siak Kecil–Bukit Batu Biosphere Reserve in Indonesia was evaluated to assess the impact of oil palm (burning and without burning) and rubber (5–10 and >40 years old) plantations on soil properties through comparisons with soils from a natural forest (NF). Substantial changes in the physico-chemical properties of soils from both plantations were observed including significant reductions in soil organic matter (4–18%) and water holding capacity (22–53%), but an increase in bulk density (ρb) (0.08–0.17?g?cm^?3). A significant increase in bacterial biomass was also observed following conversion of the NF to plantation (p<0.05). However, the oil palm plantation (OPP) (without burning) showed reduced microbial activities and the lowest Shannon diversity values (2.90) compared to other samples. Community-level physiological profiling showed impaired community function only in soils from the OPP but higher CO₂ exchange rates in most plantation soils. Soils from the rubber plantation (RP) were less impaired in terms of their natural function and therefore RPs appeared to be more suitable for sustainable agricultural use than OPP.