Annual Rice Production Research Articles

Warming increases Bacterial Panicle Blight (Burkholderia glumae) occurrences and impacts on USA rice production

Bacterial Panicle Blight (BPB), caused by Burkholderia glumae, is a bacterial disease in rice (Oryza sativa) that reduces rice yield and quality for producers and consequently creates higher market prices for consumers. BPB is caused by the simultaneous occurrence of high daily minimum temperatures (~22°C) and relative humidity (~77%), which may increase under the current scenario of global warming. This study hypothesized that the economic damage from warming may cause an increase in economic losses, though at a decreasing rate per degree. Thus, this study estimates the yield losses associated with BPB occurrences at the county level in the Mid-South United States (US) for annual rice production in 2003–2013 and under +1–3°C warming scenarios using daily weather information with appropriate thresholds. From the estimated losses, the total production potential of a BPB-resistant rice was quantified using a spatial equilibrium trade model to further estimate market welfare changes with the counterfactual scenario that all US county-level rice production were BPB resistant. Results from the study indicate that the alleviation of BPB would represent a $69 million USD increase in consumer surplus in the US and a concomitant increase in rice production that would feed an additional 1.46 million people annually assuming a global average consumption of 54 Kg per person. Under the 1°C warming scenario, BPB occurrences and production losses would cause price increases for rice and subsequently result in a $112 million USD annual decrease in consumer surplus in the US and a loss of production equivalent to feeding 2.17 million people. Under a 3°C warming scenario, production losses due to BPB cause an annual reduction of $204 million USD in consumer surplus in the US, and a loss in production sufficient to feed 3.98 million people a year. As global warming intensifies, BPB could become a more common and formidable rice disease to combat, and breeding for BPB resistance would be the primary line-of-defense as currently no effective chemical options are available. The results of this study inform agriculturalists, policymakers, and economists about the value of BPB-resistance in the international rice market and also help support efforts to focus future breeding toward climate change impact resilience.

Field Fungal Diversity in Freshly Harvested Japonica Rice

Rice is a major food crop in China and Japonica rice production in Heilongjiang Province ranks No.1 in total annual rice production in the country. Rice is prone to invasion by fungi and mycotoxins produced by the fungi are proven to be serious threats to human health. The objective of the present study was to investigate fungal diversity of freshly harvested rice in the four main cultivation regions of Heilongjiang Province in order to find the difference of dominant fungi among the four regions. Through high throughput sequencing we detected Ascomycota accounts for absolute dominant phylum; Dothideomycetes, Sordariomycetes, Tremellomycetes, Microbotryomycetes, and Eurotiomycetes were dominant classes; Capnodiales, Hypocreales, and Pleosporales were the main orders; Cladosporiaceae, Pleosporaceae, Nectriaceae, Clavicipitaceae, Tremellaceae, Phaeosphaeriaceae, Trimorphomycetaceae, Sporidiobolaceae, Bionectriaceae, and Trichocomaceae were major family; Cladosporium, Epicoccum, Fusarium, and Alternaria were the most abundant phylotypes at genus level; Epicoccum nigrum, Gibberella zeae, and Fusarium proliferatum were the dominant fungal species. Great fungal diversity was observed in the rice samples harvested in the four major Japonica rice-growing regions in Heilongjiang province. However, no significant difference in diversity was observed among the four regions, likely due to the relatively close geographical proximity leading to very similar climatic conditions. Since some of the fungal species produce mycotoxins, it is necessary to take precautions to ensure the rice is stored under safe conditions to prevent the production of mycotoxins. This is the first report on investigation of field fungal diversity in freshly harvested Japonica rice in Heilongjiang Province in China.

Technological Advancement and the Economic Benefit of Indonesian Rain-Fed Farming Development

The contribution of rain-fed farming to national food production in Indonesia has yet to be optimal. The major constraint has been limited water supply, where it relies exclusively on the rainfall, and hence its planting index (PI) is still low, on average only 1.05. The establishment of water management system to support rain-fed fields with the introduction of suitable cultivation techniques (gogo rancah, walik jerami, super jarwo, and ratoon paddy) is known to be effective in rain-fed farming. Further, the use of drought-tolerant paddy variety and changing cropping pattern to focus on paddy, maize, and soybean would potentially improve the food production capacity in Indonesia. This study has shown these interventions, when applied to the existing 4 million ha rain-fed fields, are estimated to increase annual rice production by 16.7 million tons. The production of maize and soybean is also expected to increase by 3.7 million tons and 0.98 million tons per year, respectively. It is beyond the scope of this study, however, to consider the actual benefit felt by rain-fed smallholder farmers. Future research with farmers as its focus and the capacity of Indonesian institutions toward rain-fed farming thus will contribute further to the rain-fed farming development in Indonesia. This article shares a strategy in maximising the contribution of the currently available 4 million hectares of rain-fed land to the national food production, and hence sustainable food self-sufficiency in Indonesia.

Yield gaps in intensive rice-maize cropping sequences in the humid tropics of Indonesia

Multiple crops can be grown sequentially on the same field within a 12-month period in tropical humid environments. Yield gap analysis focusing on both individual crop cycles and cropping systems can help identifying opportunities to increase annual productivity. Indonesia was used as a case study to evaluate options for increasing annual productivity in rice and maize through closure of existing yield gaps at both crop-cycle and cropping-system levels. A total of 31 (rice) and 11 (maize) sites for irrigated crops, and 24 (rice) and 29 (maize) sites for rainfed crops were selected based on their share of national harvested area. Crop modeling based on local weather, soil, and management data, together with average farmer yield data, were used to estimate yield potential and yield gaps for individual crop cycles (total: 367) and cropping systems (total: 154). Extra rice and maize production potential were estimated for different scenarios of crop intensification and/or cropland expansion and compared against projected increase in grain demand for the two crops by year 2035. Yield gaps were substantially larger in maize versus rice and, in the case of rice, yield gap was larger in rainfed lowland versus irrigated conditions. At national level, average farmer yield for irrigated rice and maize represented 63% and 44% of their respective yield potential (9.5 and 13.6 Mg ha−1) while, in rainfed conditions, average farmer yield was 52% (rice) and 42% (maize) of respective water-limited yield potential (9.2 and 12.2 Mg ha−1). Scenario assessment indicated that Indonesia can produce an extra 24 and 16 million metric tons (MMT) of rice and maize annually (respective 31 and 67% increase relative to current production) and reach near self-sufficiency for both crops on existing cropland area by closing current yield gaps to a level equivalent to 80% of yield potential (irrigated crops) or 70% of water-limited yield potential (rainfed crops). Analysis of cropping-system yield gaps indicated an additional potential increase in annual rice (3 MMT) and maize (11 MMT) production derived from adoption of crop sequences with highest annual yield potential combined with yield gap closure, though this may be limited by extra input requirements and/or increasing risk. Findings from this study demonstrate the utility of yield-gap analysis to estimate extra crop production potential derived from intensification at both individual-crop and cropping-systems levels.

A novel resistance gene for bacterial blight in rice, Xa43(t) identified by GWAS, confirmed by QTL mapping using a bi-parental population.

Bacterial blight (BB) caused by the Xanthomonas oryzae pv. oryzae (Xoo) pathogen is a significant disease in most rice cultivation areas. The disease is estimated to cause annual rice production losses of 20–30 percent throughout rice-growing countries in Asia. The discovery and deployment of durable resistance genes for BB is an effective and sustainable means of mitigating production losses. In this study QTL analysis and fine mapping were performed using an F2 and a BC2F2 population derived from a cross with a new R-donor having broad spectrum resistance to Korean BB races. The QTL qBB11 was identified by composite interval mapping and explained 31.25% of the phenotypic variation (R2) with LOD values of 43.44 harboring two SNP markers. The single major R-gene was designated Xa43 (t). Through dissection of the target region we were able to narrow the region to within 27.83–27.95 Mbp, a physical interval of about 119-kb designated by the two flanking markers IBb27os11_14 and S_BB11.ssr_9. Of nine ORFs in the target region two ORFs revealed significantly different expression levels of the candidate genes. From these results we developed a marker specific to this R-gene, which will have utility for future BB resistance breeding and/or R-gene pyramiding using marker assisted selection. Further characterization of the R-gene would be helpful to enhance understanding of mechanisms of BB resistance in rice.

Prediction of kharif rice yield at Kharagpur using disaggregated extended range rainfall forecasts

The Extended Range Forecasts System (ERFS) has been generating monthly and seasonal forecasts on real-time basis throughout the year over India since 2009. India is one of the major rice producer and consumer in South Asia; more than 50% of the Indian population depends on rice as staple food. Rice is mainly grown in kharif season, which contributed 84% of the total annual rice production of the country. Rice cultivation in India is rainfed, which depends largely on rains, so reliability of the rainfall forecast plays a crucial role for planning the kharif rice crop. In the present study, an attempt has been made to test the reliability of seasonal and sub-seasonal ERFS summer monsoon rainfall forecasts for kharif rice yield predictions at Kharagpur, West Bengal by using CERES-Rice (DSSATv4.5) model. These ERFS forecasts are produced as monthly and seasonal mean values and are converted into daily sequences with stochastic weather generators for use with crop growth models. The daily sequences are generated from ERFS seasonal (June–September) and sub-seasonal (July–September, August–September, and September) summer monsoon (June to September) rainfall forecasts which are considered as input in CERES-rice crop simulation model for the crop yield prediction for hindcast (1985–2008) and real-time mode (2009–2015). The yield simulated using India Meteorological Department (IMD) observed daily rainfall data is considered as baseline yield for evaluating the performance of predicted yields using the ERFS forecasts. The findings revealed that the stochastic disaggregation can be used to disaggregate the monthly/seasonal ERFS forecasts into daily sequences. The year to year variability in rice yield at Kharagpur is efficiently predicted by using the ERFS forecast products in hindcast as well as real time, and significant enhancement in the prediction skill is noticed with advancement in the season due to incorporation of observed weather data which reduces uncertainty of yield prediction. The findings also recommend that the normal and above normal yields are predicted well in advance using the ERFS forecasts. The outcomes of this study are useful to farmers for taking appropriate decisions well in advance for climate risk management in rice production during different stages of the crop growing season at Kharagpur.

Rice Husk-Derived Porous Silicon with High Purity As Anode for Lithium Ion Batteries

Recently, social concerns and the importance of ‘green growth’ and ‘renewed energy technology’ have increased, which resulted from the increase in the cost of fossil fuels and climate change. One of the critical technologies for accomplishing ‘green growth’ is the recycle of waste products generated through manufacturing processes. One of the largest wastes is rice husks, which are generated from the production of rice. Rice is cultivated in more than 75 countries in the world and the worldwide annual rice production amounts to approx. 422 million metric tons, of which about 20% is rice husk. However, its utilization has been limited to low-value applications in the agriculture area, such as stockbreeding rugs, bed soil, fertilization and lagging materials etc., which is the case because of their tough, woody and abrasive properties. Thus, many researchers have attempted to increase their added value, including the development of rice husks activated carbon, rice husk gasification and electricity generation. Some research groups have studied the potential of using rice husks as a fiber resource. Ah et al. reported the preparation of packing materials and Lee et al. developed a rice husk board. Rice husks contain approximately 20 wt% silica and because of ‘natural selectivity’ of rice plants, it has a lower level of metallic impurities than other representative silica sources, such as quartz, bentonite and diatomaceous earth etc.. Therefore, a significant effort has been directed at the production of high purity silicon-based materials from rice husks, such as SiC, Si3N4, SiO2 and high grade silicon. However, most of these studies are based on using rice husk ash (RHA), which is generated after the combustion of rice husk and very few studies have examined the potential of using the organic part of rice husks. Thus, we developed a refinery process to integrate the use of rice husks and increase of the value of rice husks. This process has the combined benefit of producing valuable silicon-based materials and cellulose-based materials. The rice husks are divided into fiber and inorganic components during the refinery process. In this work, we investigated the chemical composition and morphological characteristics of the rice-husk derived silica obtained from the refinery process. The conditions for preparing SiO2 with high purity and high surface area were optimized and highly porous nano-structured silicon (Si) with high purity was prepared from rice husk-derived silica. We also examined the potential of using the rice husk derived silicon as an anode material in Li-ion batteries.

English

Nigeria has abundant land and water resources to embark on irrigation schemes to ensure all year round rice production. Additional yield to annual rice production through dry season farming in 2012 in 10 pilot States of the country was found to be over 1 million metric tonnes. This shows that an intensive and consistent irrigated rice production scheme will set Nigeria on a pathway to rice self-sufficiency thereby bringing an end to the gross loss in foreign exchange due to importation and smuggling of the commodity. The study reviewed irrigation subsector in Nigeria, and revealed that the prospects of achieving rice self sufficiency through irrigation farming is hampered by some major challenges namely-underdeveloped subsector promoted by fragmented, inconsistent and unimplemented policies, multiple water regulatory institutions with overlapping and duplicating mandate and poor management system. Other challenges include- the absence of a viable market for local rice as well as high cost of labour inputs, irrigation equipments and other operating costs. The study concluded that for Nigeria irrigation potentials to be harnessed towards rice self-sufficiency there is need to amend policies on irrigation and water resources, create conducive market for local producers and provide subsidized and appropriate farm implements. Key words: Irrigation potentials, rice self-sufficiency, challenges, Nigeria.

Yield Forecasting Models based on Weather Parameters for Eastern U.P.

Yield Forecasting Models based on Weather Parameters for Eastern U.P. In the present study, attempts have been made to development of pre harvest models for pre harvesting forecasting of rice yield at district level on the basis of generated weather variables. Weekly data (14 meteorological weeks) because Time of the pre harvest forecast is 14th week 2½ month before harvesting flowering stage and seven weather variables over a span of 20 years period (1995 to 2014) has been used along with the annual rice production data for respective year for eastern UP. The data of de-trend yield and generated weather variables for 18 years of has been used for generation of the models. (1995-2012). Total five models were validated with 2 year independent data set (2013 and 2014). The (PPE) ranging - 4.32 to 10.56 % from the observed yield for all 5 models. Highest correlation has been found 0.68 between Z231 (Weighted interaction between MaxT and MinT). Significance of models are obtained by on the basis of highest R2 (86%) and by (P-value) (0.08). MBE (Mean Biased Error), RMSE (Root Mean Square Error) and PE (Percent Error) has been used for the Error analysis. On the basis of R2 and other parameter the model IV has been found best..

Socio-Demographic Factors Contributing to the Productivity in Paddy Farming: A Case Study

According to 2010 statistics, paddy cultivation had been the livelihood of more than 1.8 million farm families in Sri Lanka. The annual rice (Oryza sativa L.) production of 2.1 million tons in 1980 had increased to 4.3 million tons in 2010. Paddy farmers are mutually benefitted from group activities. This study examined the sociodemographic factors contributing to the success of paddy farmers in the Dry Zone of Sri Lanka with a focus on the innovation and adoption of new practices, farming experience, knowledge sharing and team behaviour among farmers. Their perceptions about farming as a career, productivity, and profitability in paddy farming were analyzed. Impact of gender on paddy farming practices was examined. Sixty three paddy farmers (32 males, and 31 females) were selected for the study from Polpithigama Divisional Secretariat area based on stratified random sampling. Mann-Whitney test, Wilcoxon rank-sum test, Correlation, and Chi-square tests were used for inferential analysis of data along with descriptive analysis. Knowledge sharing behaviour in farming correlated strongly with the respondents’ perception of farming as a career. Knowledge sharing correlated moderately with their farming experience. Innovation and adoption of new practices was the major contributing factor in the productivity of paddy farming. Significant differences were observed between gender and farming practices, with male farmers recording superior performances over female farmers in many farming practices. Tropical Agricultural Research Vol. 25 (3): 437-444 (2014)

Aerobic Rice Production System(ARPS): Improving Productivity and Profitability in Water-Scarce Areas of Bulacan

On-farm study on rice-based cropping system following recent water-saving technologies for rice production such as ARPS-ARPS, ARPS-alternate wetting and drying (AWD) and existing or Farmers’ Practice (FP) was conducted in a rainfed lowland area in Brgy. Mataas na Parang, San Ildefonso, Bulacan. Field experiments were conducted from June to November 2011 for the wet season and December 2011 to March 2012 for the dry season. Variety used for the ARPS and AWD was NSIc Rc192 and PSB Rc18 for FP. Yield and yield components of the three treatments showed no significant difference during WS. Significant higher number of tillers hill was observed for ARPS-ARPS and -1 ARPS-AWD compared to FP. No significant difference was observed for the yield and yield components during the dry season (DS) for ARPS-ARPS and ARPS-AWD. FP was not established during the DS because of the unavailability of water during the time. During WS, ARPS was the most appropriate cropping system since this intervention obtained higher water productivity and ROI when compared with the FP. During the dry season, AWD and ARPS were suitable to the rainfed lowland areas of Bulacan. Results of this study showed that aerobic rice production system for the rainfed lowland areas improved water and land productivity as well as increased annual rice production and farmers’ income most particularly in ARPS-AWD which consistently gave the highest net income of PhP36,896.20, PhP14,417.50 and PhP51,313.70 during the Wet Season, Dry Season and for the total two cropping seasons, respectively

Decadal reduction of Chinese agriculture after a regional nuclear war

AbstractA regional nuclear war between India and Pakistan could decrease global surface temperature by 1°C–2°C for 5–10 years and have major impacts on precipitation and solar radiation reaching Earth's surface. Using a crop simulation model forced by three global climate model simulations, we investigate the impacts on agricultural production in China, the largest grain producer in the world. In the first year after the regional nuclear war, a cooler, drier, and darker environment would reduce annual rice production by 30 megaton (Mt) (29%), maize production by 36 Mt (20%), and wheat production by 23 Mt (53%). With different agriculture management—no irrigation, auto irrigation, 200 kg/ha nitrogen fertilizer, and 10 days delayed planting date—simulated national crop production reduces 16%–26% for rice, 9%–20% for maize, and 32%–43% for wheat during 5 years after the nuclear war event. This reduction of food availability would continue, with gradually decreasing amplitude, for more than a decade. Assuming these impacts are indicative of those in other major grain producers, a nuclear war using much less than 1% of the current global arsenal could produce a global food crisis and put a billion people at risk of famine.

Aerobic Rice Production System(ARPS): Improving Productivity and Profitability in Water-Scarce Areas of Bulacan

On-farm study on rice-based cropping system following recent water-saving technologies for rice production such as ARPS-ARPS, ARPS-alternate wetting and drying (AWD) and existing or Farmers’ Practice (FP) was conducted in a rainfed lowland area in Brgy. Mataas na Parang, San Ildefonso, Bulacan. Field experiments were conducted from June to November 2011 for the wet season and December 2011 to March 2012 for the dry season. Variety used for the ARPS and AWD was NSIc Rc192 and PSB Rc18 for FP. Yield and yield components of the three treatments showed no significant difference during WS. Significant higher number of tillers hill-1 was observed for ARPS-ARPS and ARPS-AWD compared to FP. No significant difference was observed for the yield and yield components during the dry season (DS) for ARPS-ARPS and ARPS-AWD. FP was not established during the DS because of the unavailability of water during the time. During WS, ARPS was the most appropriate cropping system since this intervention obtained higher water productivity and ROI when compared with the FP. During the dry season, AWD and ARPS were suitable to the rainfed lowland areas of Bulacan. Results of this study showed that aerobic rice production system for the rainfed lowland areas improved water and land productivity as well as increased annual rice production and farmers’ income most particularly in ARPS-AWD which consistently gave the highest net income of PhP 36,896.20, PhP 14,417.50 and PhP51,313.70 during the Wet Season, Dry Season and for the total two cropping seasons, respectively

Nitrogen Management and Methane Emissions in Direct‐Seeded Rice Systems

Rice (Oryza sativa L.) establishment systems based on resource‐conserving production practices are gaining popularity globally. To investigate the potential for improved N management and mitigation of methane (CH4) emissions, field experiments were conducted in California on three crop establishment systems: water‐seeded (WS) conventional, WS stale seedbed, and drill‐seeded (DS) stale seedbed. Fertilizer nitrogen recovery efficiency (NRE) and rice yield as affected by N rate, source, and application timing were evaluated for 2 yr in each system. Methane emissions were monitored over a full annual rice production cycle (growing season plus fallow period). Results indicated that neither split N applications nor ammonium sulfate increased yields or NRE compared with a single application of urea, regardless of system. However, the economic optimum N rate increased by approximately 30 kg N ha−1 in WS stale seedbed compared with the conventional system. Since NRE generally remained similar across N treatments that maximized yields, applying the appropriate N rate as a single dose before the permanent flood would satisfy both agronomic and environmental goals of N management within each system. Both WS systems resulted in similar growing season CH4 emissions. However, the DS system reduced CH4 emissions by 47% compared with the conventional WS system, possibly due to a decreased period of anaerobic soil conditions. This study highlights the importance of assessing benefits as well as tradeoffs when evaluating opportunities for increasing the sustainability of direct‐seeded establishment systems with respect to N management and CH4 emissions.

Design and Development of Artificial Neural Networking (ANN) System Using Sigmoid Activation Function to Predict Annual Rice Production in Tamilnadu

Prediction of annual rice production in all the 31 districts of Tamilnadu is an important decision for the Government of Tamilnadu. Rice production is a complex process and non linear problem involving soil, crop, weather, pest, disease, capital, labour and management parameters. ANN software was designed and developed with Feed Forward Back Propagation (FFBP) network to predict rice production. The input layer has six independent variables like area of cultivation and rice production in three seasons like Kuruvai, Samba and Kodai. The popular sigmoid activation function was adopted to convert input data into sigmoid values. The hidden layer computes the summation of six sigmoid values with six sets of weightages. The final output was converted into sigmoid values using a sigmoid transfer function. ANN outputs are the predicted results. The error between original data and ANN output values were computed. A threshold value of 10-9 was used to test whether the error is greater than the threshold level. If the error is greater than threshold then updating of weights was done all summations were done by back propagation. This process was repeated until error equal to zero. The predicted results were printed and it was found to be exactly matching with the expected values. It shows that the ANN prediction was 100% accurate.

Effect of transgenic insect-resistant rice on biodiversity

Rice is the most important food crops in maintaining food security in China. The loss of China's annual rice production caused by pests is over ten million tons. Present studies showed that the transgenic insect-resistant rice can substantially reduce the application amount of chemical pesticides. In the case of no pesticide use, the pest density in transgenic rice field is significantly lower than that in non-transgenic field, and the neutral insects and natural enemies of pests increased significantly, indicating that the ecological environment and biodiversity toward the positive direction. The gene flow frequency from transgenic rice is dramatically reduced with the distance increases, reaching less than 0.01% at the distance of 6.2 m. Application of transgenic insect-resistant rice in China has an important significance for ensuring food security, maintaining sustainable agricultural development, and protecting the ecological environment and biodiversity. This review summarized the research progress in transgenic insect-resistant rice and its effect on biodiversity. The research directions and development trends of crop pest controlling in future are discussed. These help to promote better use of transgenic insect-resistant rice.

Fluidised bed combustion and gasification of rice husk and rice straw – a state of art review

Rice is cultivated in all the main regions of world. The worldwide annual rice production is 666 million tons for the year 2008. The combustion and gasification of rice husk/rice straw in fluidised bed reactors seems to be an attractive possibility of future for power generation, the solution of waste disposal problems and the reduction of greenhouse gases. In this paper, overview of fluidised bed reactors based on rice husk/rice straw and some data collected/measured from rice husk-rice straw power plant is presented. Combustion efficiency from 60% to 98%, combustion at bed temperature from to 600°C–850°C, carbon conversion efficiency up to 98% and cold gas efficiency up to 67% is reported. Gas heating value up to 6.6 MJ/m 3 and 5.5 MJ/kg is reported. Combustion intensity up to 530 kg/h/m 2 is reported. SOx and NOx emitted from fluidised bed combustors based on rice husk and rice straw are generally very less under normal operating conditions.

Impact of Recent Severe Floods on Rice Production in Bangladesh

The long-term variations of rice production in Bangladesh are examined in the latter half of the 20th century and the impact of recent severe floods is discussed. Unprecedented severe floods, which submerged nearly two thirds of the country, occurred recently in Bangladesh in 1988 and 1998, and the effects of these severe floods to rice cropping are revealed. In these severe flood years, the rainy season crop aman drastically declined in production due to the decrease of the cultivated area and yield. On the other hand, the dry season crop boro, which is planted after the flood withdrawal, increased its production much higher than that of the previous year, mainly because of utilization of the residual flood water. In terms of total annual rice production, it turns out that severe floods have even a positive effect on rice production in Bangladesh. Furthermore, rice production after these severe flood years is higher than that of the previous years, suggesting that severe floods may act as a trigger for increasing rice production level through the change of the hydrological environment and farmers' reaction to it.

Do Markets Worsen Economic Inequalities? Kuznets in the Bush

Integration into a market economy or economic development can erode the quality of life of indigenous people by, for example, increasing income inequalities. The Kuznets hypothesis predicts that the link between income inequality and income (a proxy for economic development) resembles an inverted U. We test the hypothesis using a survey of 511 households from 59 villages of Tsimane' Amerindians, a horticultural-foraging society in the tropical rain forest of Bolivia. We measure village inequalities of three economic outcomes: income, imputed annual value of rice production, and wealth. We used three indices of inequality: the coefficient of variation, the standard deviation of the logarithm, and the Gini coefficient. Explanatory variables include either income and income squared, wealth and wealth squared, or imputed annual rice production and production squared. We used village-to-town distance as a control. We find little evidence that integration to the market increases inequalities of economic outcomes, with two exceptions: Wealth bore the predicted inverted U-shaped relation with wealth inequalities, and imputed rice production bore a U-shaped relation to inequality, but only when (a) using adult equivalents to express household size and (b) the Gini coefficient and the coefficient of variation to measure inequality; in no case were results robust to different econometric specifications. We advance several explanations for why economic development might not accentuate economic inequalities among relatively autarkic rural economies.

Advance estimation of rice production in India using weather indices

Estimation of crop production from area and yield estimates based on sample surveys and crop-cutting experiments, an approach currently being followed in India, can give final estimates only after the crops are actually harvested. However, various policy decisions related to pricing, marketing, export/import, distribution, etc., necessitate the use of advance estimates. A simple model based on weather indices can be used to obtain accurate estimates of annual rice production even before the crop is harvested. Crop production in India largely depends on the summer monsoon (June to September), which provides about 80–90% of annual rainfall in most parts of the country. The summer monsoon rainfall is the main source of water for the kharif crop. Rainwater stored as soil moisture and other water resources (lakes, reservoirs, and rivers) are also important for the– rabi– and other irrigated crops. Parthasarathy et al (1988) have estimated the annual food-grain production in the country using the all-India summer monsoon rainfall data. The rainfall data, however, showed significant variations in time and space. To obtain more accurate production estimates, the temporal and spatial variations of monsoon rainfall were also included in the model through suitable weather indices.