Rice Yield In China Research Articles

Adapting Seasonal Rice Cultivation Strategies for Food Security in Response to Climate Change Impacts

An in-depth examination of the effects of climate change on rice yield in China, encompassing various rice types, is crucial for ensuring the nation’s food security. This study develops an “economy-climate” theoretical model and employs Panel Corrected Standard Error Estimation (PCSE) on panel data spanning from 1978 to 2018, sourced from China’s primary grain-producing regions. The analysis delves into the impact of climate variables, including precipitation, temperature, and sunshine duration, on overall rice production and different rice types. Overall, the findings reveal a nonlinear relationship between precipitation, temperature, sunshine duration, and rice yield, characterized by an “inverted U-shaped” pattern. However, significant variations exist in the effects on different rice types across China’s main grain-producing areas. Increasing precipitation generally enhances early rice production across provinces and also augments mid-season and one-season-late rice production in the Inner Mongolia Autonomous Region, Hebei, Jilin, Heilongjiang, and Shandong Province. Conversely, it reduces mid-season and one-season-late rice output in Liaoning, Jiangsu, Anhui, Jiangxi, Henan, Hubei, and Hunan. Sichuan Province sees a rise in temperature favoring early and double-season-late rice production, unlike other provinces. For mid-season and one-season-late rice, temperature increases benefit output in Heilongjiang Province but not in other regions. Additionally, prolonged sunshine duration boosts early and double-season-late rice production across all provinces but does not have the same effect on mid-season and one-season-late rice in China’s primary grain-producing areas.

Optimizing the rate of straw returning to balance trade-offs between carbon emission budget and rice yield in China

Rice paddies are a prominent contributor to greenhouse gases (GHGs) emissions, accounting for 22 % of the overall agricultural methane (CH4) emissions. Although returning rice straw to the field can increase yield and soil organic carbon (SOC), the significant GHGs released during this process often negate these positive effects. Thus, understanding the impact of straw returning on the relationship between rice yield and GHGs is crucial for farming adaptation and climate change mitigation. This study aims to investigate the effects of varying straw returning rates on rice yield and GHGs in China and identify the optimal rates on a provincial scale. This study utilized county-level meteorological, soil, and field management data. The Dynamic Nitrogen and Carbon Model (DNDC) model was used to simulate the impacts on rice yield, GHGs, and SOC changes under different straw returning rates in China from 2010 to 2022, including no straw, 1/3, 2/3, and full straw returning. The results showed that 1/3, 2/3, and full straw incorporation increased rice yield per unit area by 1.07 %, 2.25 %, and 3.26 % for single rice cropping, 1.10 %, 2.24 %, and 3.52 % for early rice, and 1.92 %, 3.91 %, and 5.95 % for late rice, respectively. Compared with no straw returning, the total SOC content (0–50 cm) increased by 3.88 % (78.07 Tg), 7.75 % (156.09 Tg), and 11.65 % (234.62 Tg) under 1/3, 2/3, and full straw returning, respectively. However, the total GHGs were increased by 23.32 %, 43.50 %, and 61.48 % for 1/3, 2/3, and full straw incorporation compared to no straw returning. While the overall benefits of straw returning varied across regions, in certain areas like northeastern China, Xinjiang, and Yunnan, an increase in straw returning rates leads to a significant increase in yield with a relatively smaller increase in GHGs. This can be attributed to factors such as lower temperatures, decreased SOC, and lower soil pH, restricting CH4 production. Conversely, in regions with higher soil pH, such as north China and the Sichuan Basin, as well as in warmer southern areas, the increase in GHGs is quite pronounced. In summary, implementing straw returning significantly increases rice production and SOC but simultaneously increases GHGs. In China, the most widespread utilization of rice straw remains straw returning. We have summarized the average impact of straw returning on yield, SOC, and GHGs, and proposed straw returning rates tailored to the comprehensive benefits in different regions, to enhance the carbon sequestration and emission reduction rate of rice straw returning.

Integrated Straw Return with Less Power Puddling Improves Soil Fertility and Rice Yield in China’s Cold Regions

The rice production system in China is facing challenges, including declining soil fertility and a stagnant rice yield. This study aimed to test whether integrating the return of straw to fields with less power puddling could simultaneously enhance soil fertility and rice yields. Therefore, field experiments were conducted in Heilongjiang Province, a key rice-growing region in China, from 2017 to 2021, using three different planting methods: control group (CK), straw return (SR) and straw return integrated with less power puddling (SR + LP). The results showed that small soil aggregates (particle diameter < 0.25 mm) and soil bulk density were significantly decreased when straw return was integrated with less power puddling. These changes contributed to the preservation of soil structure. Simultaneously, this approach significantly increased soil ammonium nitrogen content from 9.9 to 10.9 mg kg−1, organic matter content from 35.0 to 36.2 g kg−1, available nitrogen content from 140.5 to 147.0 mg kg−1 and available potassium content from 128.6 to 136.8 mg kg−1 at mature stage on average. Consequently, the post-heading stored assimilates accumulation of rice was increased from 6.12 to 6.43 t ha−1, and the nitrogen, phosphorus and potassium accumulation of rice were increased by 7.85 kg ha−1, 1.13 kg ha−1 and 5.68 kg ha−1, respectively. These changes ultimately resulted in a higher 1000 g weight and filled grain rate, providing the foundation for higher yields (an increase from 9.31 t ha−1 to 9.55 t ha−1). Furthermore, this approach also increased the net income for farmers by USD 14 t ha−1. In summary, this study demonstrates that integrating straw return with less power puddling can enhance soil’s nutrient supply and retention capacity. This enhancement may boost the absorption and transportation of nutrients, ultimately establishing the groundwork for higher yields and economic benefits by enhancing the 1000 g weight and filled grain rate. Future research should delve deeper into its applicability across different ecosystems and investigate the yield-increasing mechanisms.

Regional inequalities of future climate change impact on rice (Oryza sativa L.) yield in China

The implications of climate change for rice yield have significant repercussions for food security, particularly in China, where rice cultivation is diverse, involving various cropping intensities, management practices, and climate conditions across numerous regions. The regional discrepancies in the impact of climate change on rice yield in China, however, are yet to be fully understood. Using the ORYZA(v3) model and future climate data from 2025 to 2084, gathered from ten climate models and three climate change scenarios (RCP2.6, RCP4.5, and RCP8.5), we conducted an investigation into these regional discrepancies. Our findings suggest a projected average decline in rice yield ranging from 3.7 % to 16.4 % under both rainfed and fully irrigated conditions across different scenarios. Central, eastern, and northwestern China could face the most significant climate change impacts on both rainfed and irrigated rice, with yield reductions reaching 41.5 %. In contrast, low levels of climate change under the RCP2.6 scenario may benefit northeastern (2.4 %) and southern (1.0 %) regions for rainfed and irrigated rice, respectively. Fertilization effects from elevated CO2 could counterbalance climate change's negative impact, resulting in yield increases in all Chinese rice-growing regions, excluding the northwest. The primary factor influencing rice yield changes in all regions under the RCP4.5 and RCP8.5 scenarios was temperature. However, precipitation, solar radiation, and relative humidity had notable and sometimes dominant effects, especially under the RCP2.6 scenario. These results highlight the divergent, even contradictory, rice yield responses to climate change across China, underlining the need to account for regional differences in large-scale impact studies. The study's findings can inform future policy decisions regarding ensuring regional and national food security in China.

Extreme rainfall reduces one-twelfth of China's rice yield over the last two decades.

Extreme climate events constitute a major risk to global food production. Among these, extreme rainfall is often dismissed from historical analyses and future projections, the impacts and mechanisms of which remain poorly understood. Here we used long-term nationwide observations and multi-level rainfall manipulative experiments to explore the magnitude and mechanisms of extreme rainfall impacts on rice yield in China. We find that rice yield reductions due to extreme rainfall were comparable to those induced by extreme heat over the last two decades, reaching 7.6 ± 0.9% (one standard error) according to nationwide observations and 8.1 ± 1.1% according to the crop model incorporating the mechanisms revealed from manipulative experiments. Extreme rainfall reduces rice yield mainly by limiting nitrogen availability for tillering that lowers per-area effective panicles and by exerting physical disturbance on pollination that declines per-panicle filled grains. Considering these mechanisms, we projected ~8% additional yield reduction due to extreme rainfall under warmer climate by the end of the century. These findings demonstrate that it is critical to account for extreme rainfall in food security assessments.

Meta-Analysis of Factors Affecting C-N Fractions and Yield of Paddy Soils by Total Straw Return and N Fertilizer Application

The effective use of nutrient-rich crop straw is an important way to use resources efficiently and to sustain agricultural development. This meta-analysis study collected and analyzed the data of 6788 observations published in 238 peer-reviewed papers to investigate differences in soil C-N fractions and yields of paddy soils under different straw-return amounts. This large dataset was also used to quantify the degree of influence of factors such as climate characteristics, soil properties, N fertilizer application rates, straw-rotting agent addition, rice varieties, and straw return methods. The results showed that straw return amounts improved soil alkaline-hydrolysable N (7%), total N (10%), organic C (11%), the C:N ratio (8%), rice N accumulation (12%), and overall yield (18%). The most significant effect was in northeast China fields for total soil nitrogen (TN) content and yield with increases of 13% and 22%, respectively. We also found more effective N utilization and a greater rice yield when 220–260 kg ha−1 N fertilizer was applied with 20–30 kg ha−1 straw-rotting agent with the total amount of straw return. These findings have important implications for choosing appropriate conditions and field management practices and to improve rice yield in China.

Impacts of Climate Change on the Mean and Variance of Indica and Japonica Rice Yield in China

The overall goal of this study was to examine the impacts of climate change on the mean and variance of rice yields in China by using historical climate and crop data. An econometric model was established to estimate Just–Pope stochastic production functions and identify the potential impacts of climate change on the mean and variance of rice yields by type, keeping other factors constant. Based on the estimated production functions, the contribution rate of climatic factors to rice yield was then assessed by conducting the growth accounting of yields over the past 30 years. The results showed that both the mean rice yield and the yield variability were influenced by changes in the mean climate conditions and climatic variance. In the future, the impacts of climate change on rice yields will depend on local regions’ present climatic conditions. The results have implications for improving the adaptation capacity of rice production.

Heat stress may cause a significant reduction of rice yield in China under future climate scenarios

Extreme heat events have become more frequent and severe under climate change and seriously threaten rice growth. Most existing crop models tend to underestimate the impacts of heat stress on rice yields. Heat stress modules in crop models have not been extensively explored, particularly on a large scale. This study modeled rice growth under heat stress at the flowering and filling stages through two heat stress models which coupled into the CERES-Rice model. We evaluated the advanced model with provincial statistics and Gridded Observed Rice Yield. Our improved CERES-Rice model produced more accurate estimates on rice yield than the original model evidenced by an increased correlation coefficient (R) of 12.72% and d-index of 0.02%. The RMSE and MAE decreased by 5.94% and 6.01%, respectively. Most pseudo positive correlations between rice yield and the number of heat days were corrected to the negative ones by the improved model. The future projections from the improved model signifies multi-model ensemble yield projection without CO2 effect (MME-I-NOCO2) has an apparent fall from 2020 to 2099 under RCP4.5, RCP6.0 and RCP8.5 with the decreasing percentages of 6%, 14%, and 37%, respectively, whereas the decreasing trend (12%) only occurs under RCP8.5 with CO2 effect (MME-I-CO2). The apparently decreasing trends of yield projection from MME-I-NOCO2 will occur in most rice-planted regions of China with the decreasing rate < 50 kg/ha/a especially in the central-south and southern cropping regions, and this decreasing trend will be slowed down for MME-I-CO2. Relative to rice yield of historical period, rice yield variations of MME-I-NOCO2 for different growing seasons show a downward trend with the decrease of approximately 54%, 60%, and 43%, respectively. Our study highlights the importance of modeling crop yields under heat stress to food security, agricultural adaptation and mitigation to climate change.

Progress and Prospect of Breeding Utilization of Green Revolution Gene SD1 in Rice

Rice (Oryza sativa L.) is one of the most important cereal crops in the world. The identification of sd1 mutants in rice resulted in a semi-dwarf phenotype that was used by breeders to improve yields. Investigations of sd1 mutants initiated the “green revolution” for rice and staved off famine for many people in the 1960s. The smaller plant height conferred by sd1 allele gives the plants lodging resistance even with a high amount of nitrogen fertilizer. Guang-chang-ai-carrying sd1 was the first high-yielding rice variety that capitalized on the semi-dwarf trait, aiming to significantly improve the rice yield in China. IR8, known as the miracle rice, was also bred by using sd1. The green revolution gene sd1 in rice has been used for decades, but was not identified for a long time. The SD1 gene encodes the rice Gibberellin 20 oxidase-2 (GA20ox2). As such, the SD1 gene is instrumental in uncovering the molecular mechanisms underlying gibberellin biosynthesis There are ten different alleles of SD1. These alleles are identified by genome sequencing within several donor lines in breeding for semi-dwarf rice. Apart from breeding applications and the molecular mechanism of GA biosynthesis, the SD1 gene is also involved in the molecular regulation of other important agronomic traits, like nitrogen fertilizer utilization. The dentification of new alleles of SD1 can be obtained by mutagenesis and genome editing. These new alleles will play an important role in improving the resource diversity of semi-dwarf breeding in the future.

Possible trends of rice yield in China under global warming by 1.5 ℃ and 2.0 ℃

Possible trends of rice yield in China under global warming by 1.5 ℃ and 2.0 ℃

How Does Climate Change Affect Rice Yield in China?

The global warming phenomenon has undoubtedly brought unprecedented challenges to rice production, vital for food security in Southeast Asian countries and China. Most studies on this topic have focused narrowly on the direct effect of climate change on rice yield, neglecting the indirect effect. Using panel data from 30 provinces in China from 1990 to 2016, in this paper, we propose and test a mediational effect model to examine the mechanisms of how climate change affects rice yield. We find that climate change leads to changes in functional irrigation areas, farmers’ fertilizing behavior, and agricultural labor supply, and it is these mediating factors that effectively transmit the impact of climate change to China’s rice production. The positive indirect impact of climate change on the factors of production often partially or overly compensates for the adverse direct effect of climate change on rice yield, leading to a surprising observation of the association of climate change with increased rice yield, at least in the short run. We also provide some preliminary policy advice based on the analysis.

Changes in rice yield and yield stability in China during the past six decades.

Increasing rice yield and its stability are important to achieving the sustainability of rice production. Rice yields have increased substantially in China during recent decades, but information on the trend in yield stability has been limited. In this study, the trends in rice yield and rice yield stability from 1949 to 2015 were analysed in China's rice production. The results showed that rice yields for all 16 provinces presented an increasing trend during the study period. The national annual rice yield gain was 86.0 kg ha-1 during the last six decades, varying from 48.4 to 106.0 kg ha-1 in different provinces and exhibiting linear, bilinear, or trilinear relationships. Remarkably, the annual yield increase was smaller in provinces dominated by double rice cropping systems than in the other provinces. Notably, rice yield stagnations have occurred in recent years at provincial and national levels. Absolute residuals over time showed slight increases in four of 16 provinces, indicating a reduction in yield stability in these four provinces. However, the relative yield residuals exhibited a clear trend towards increased yield stability for all 16 provinces. The rice yields of newer cultivars planted with improved crop management practices were consistently higher and more stable than with cultivars from the beginning of the study period. This study revealed that rice yield in China has increased substantially, accompanied by improved stability over the last six decades. Given the spatial difference, this study emphasizes the priority of orienting long-term on-farm studies to investigate yield stability. © 2020 Society of Chemical Industry.

심층신경망을 이용한 중국의 쌀 수확량 예측 실험

Global warming due to the increase of greenhouse gases may significantly affect various aspects of the Earth’s environment and human life. In particular, the impacts of climate change on agriculture would be severe, leading to damages to crop yields. This paper examines the experimental prediction of rice yield in China using DNN (deep neural network) and climate model data for the period between 1979 and 2009. The DNN model built through the process of hyperparameter optimization can mitigate an overfitting problem and cope with outlier cases. Our model showed approximately 38.7% improved accuracy than the MLR (multiple linear regression) model, in terms of correlation coefficient with the yield statistics. We found that the diurnal temperature range and potential evapotranspiration were the critical factors for rice yield prediction. Our DNN model was also robust to extreme conditions such as drought in 2006 and 2007 in China, which showed its applicability to the future simulation of crop yields under climate change.

Impacts of Sulfate Geoengineering on Rice Yield in China: Results From a Multimodel Ensemble

AbstractSulfate geoengineering could mitigate global warming via injecting SO2 into the stratosphere. However, its impacts on regional climate might lead to adverse consequences for local agriculture. In this study, we simulated the impacts of sulfate geoengineering on rice yield in China both with sufficient irrigation (irrigated) and without irrigation (rainfed). We used Geoengineering Model Intercomparison Project G4 climates from six climate models to force the ORYZA version 3 crop model to simulate rice yields under sulfate geoengineering scenario. G4 prescribes a sulfate injection to offset the radiative forcing in the Representative Concentration Pathway (RCP) 4.5 scenario. Results indicated that during the last 15 years of G4 sulfate geoengineering (i.e., 2055–2069), the implementation of sulfate geoengineering increases rice yields in most areas in China comparing with that without the implementation of sulfate geoengineering (i.e., RCP4.5), with a yield increase of 5.3 ± 5.7% for irrigated yield and 4.8 ± 7.3% for rainfed yield. After the termination of sulfate geoengineering, the irrigated rice yield in G4 is still significantly higher than that in RCP4.5, but such increase is not significant for rainfed yield. Temperature is always the dominant factor that drives the rice yield change no matter under irrigated or rainfed conditions, but the effect from solar radiation cannot be ignored in southern China.

Climate change and geographic shifts in rice production in China

Climate change can affect crop yield in a given location, and it can also affect where crops are grown. Most assessments of the effect of historical climate change on crop yield has been at the national level, ignoring possibly important subnational variation and climate change adaptation through changes in crop distribution. We analyzed the relationship between growing season temperature, rice yield, and the spatial distribution of rice production in China between 1949 and 2015. Since 1949, rice production in China has moved northwards. Because of this, country level average temperature for rice areas during the growing season was relatively stable, and colder than it would have been without the movement. Temperature has had a very small effect on rice yield at the country level of −0.05 t ha−1 °C−1. However, this masks important subnational variation. Increased temperatures were associated with an increase in rice yield (0–1.0 t ha−1 °C−1) in northern provinces and a decrease (−0.6–0 t ha−1 °C−1) in southern provinces of China. While the estimated overall effect of the northward movement on average rice yield in China was only 162 kg ha−1, it does illustrate how crop movements can modify climate change effects and can be an emergent adaptation strategy.

China feels the heat: negative impacts of high temperatures on China's rice sector

We analysed a county‐level data set of single‐season rice yield and daily weather outcomes in China to examine the effects of temperature on China's rice sector. We found that rice yield exhibited highly nonlinear responses to temperature changes: rice yield increased with temperature up to 28°C and decreased sharply with higher temperatures. Holding current growing seasons and regions constant, average rice yield in China is projected to decrease by 10–19 per cent by 2050 and 11–33 per cent by 2070 due to future warming under the global climate models HadGEM2‐ES and NorESM1‐M. These results imply that future warming poses a major challenge for Chinese rice farmers and that the effectiveness of adaptations will depend on how well they reduce the negative temperature impacts on rice yield because of very hot days.

High‐Temperature Episodes with Spatial‐Temporal Variation Impacted Middle‐Season Rice Yield in China

Core Ideas Quantified high‐temperature intensity, frequency, and duration as HDH index.High‐temperature episodes between booting and flowering increased significantly.High‐temperature episodes had a significant negative effect on rice yield. Booting and flowering stages of rice are most sensitive to high‐temperature episodes. However, the effect of spatial‐temporal characteristics of high‐temperature episodes on booting and flowering stages in the middle‐season rice cropping region of China were less commonly found in the literature. A data analysis of historical climate and rice yield was conducted to characterize the spatial and temporal variability of high‐temperature episodes between booting and flowering stages and their impact on middle‐season rice grain yield in China. Three high‐temperature indices, including high‐temperature hours (HH), high‐temperature intensity (HI), and high‐temperature degree hours (HDH), were developed to quantify the high‐temperature intensity, frequency, and duration based on maximum temperature records of the last 30 yr from 219 stations in the main middle‐season rice cropping area of China. The HH and HI indices between booting and flowering stages increased significantly in all subregions. Especially in the Central China (CC) subregion, high‐temperature episodes were more severe than those in the East China (EC) subregion and Southwest (SW) subregion. The HDH index, considering the duration and intensity of high‐temperature episodes, was required to describe the correlation between high‐temperature episodes and yield variability. Significant negative (p &lt; 0.05) impacts of the variability of high‐temperature episodes on the observed grain yield were found in all subregions. Rice yield would decrease by 113.9 kg ha−1, 19.1 kg ha−1, and 22.2 kg ha−1 with an HDH increase of 1.0°C·d in the EC, CC, and SW subregions, respectively. High‐temperature episodes were detrimental to middle‐season rice production of China.

Estimating the average treatment effect of adopting stress tolerant variety on rice yield in China

Climate extremes, characterized by droughts and floods, have become one of the major constraints to sustainable improvement of rice productivity. Variety choice, considered as one of the main adaptation measures, could help farmers reduce yield loss resulting from these extremes. Based on a three-year panel survey of 1 080 Chinese rice farms in major rice producing provinces, we assume Hicksian neutral technology and employ an IV regression to estimate the average treatment effect (ATE) on rice yield for adopting stress tolerant variety, and find that farmers who adopted the stress tolerant variety on average increased rice yield by 15.5% in comparison to the non-adopters.

Future extreme temperature and its impact on rice yield in China

ABSTRACTRice in China is increasingly suffered from extreme temperature stress (ETS) with ongoing climate change. It is projected that ETS would increase notably across the world in the future. However, the spatio‐temporal change of ETS in main rice planting areas in China is still unclear; and the future yield loss caused by ETS (YLETS) has seldom been investigated quantitatively. In this study, we first investigated the spatio‐temporal change of ETS across China under 20 climate change scenarios consisting of five global climate models and four Representative Carbon Pathways (2.6, 4.5, 6.0, and 8.5). Then, using a process‐based crop model (MCWLA‐Rice), its 30 sets of model parameters and the 20 climate change scenarios, we conducted a super‐ensemble assessment to investigate the YLETS over 2020–2049, relative to the baseline period (1980–2009), across China. The results showed that, an increased heat ETS and a decreased cold ETS would be expected for most areas. As a result, a large spatial variability of yield loss would be expected in the future, including severely cold stress for region I (northeastern China, single rice) and region IV (southern China, early rice), but severely heat stress for region III (the middle and lower reaches of Yangtze River, single rice) and region IV (southern China, late rice). Comparing yield loss from both ETS, a decreased change in yield loss would be mainly expected in region I (northeastern China, single rice), while an increased change for region III (the middle and lower reaches of Yangtze River, single rice) and IV (southern China, late rice), with less change for region II (southwestern China, single rice) and IV (southern China, early rice). Finally, some adaptation measures were proposed for the ETS‐sensitive areas. Our findings are useful to develop effective policies to cope with climate risk and relieve ETS disasters.

Progress of super hybrid rice research in China

To meet the growing food demands in China, a program of super rice breeding was set up by the Chinese Ministry of Agriculture in 1996. The goals of this program is to achieve rice yield targets to 10.5, 12.0, 13.5, and 15.0 t/ha in single season rice growing area through four research phases. A proposed model of combining morphological improvement with the utilization of inter-subspecific ( indica / japonica ) heterosis, by Prof. Yuan LongPing in 1997, played a leading contribution for the program of super hybrid rice breeding. Until now, all yield targets of four phases have been achieved. The pioneer super hybrid rice variety, Liangyoupeijiu, met the Phase I yield target in 2000. The Phase II super hybrids were successfully developed in 2004. Y Liangyou No.1 (YLY1), the typical Phase II super hybrid rice variety, has a largest annual planting area among all hybrid rice varieties in China since 2010 and has been extended to more than 4 million hectare so far. Y Liangyou No.2 (YLY2) met the standard of phase III super rice with a yield record of 926.6 kg/mu (13.9 t/ha) in 2011. The breeding target of Phase IV super hybrid was achieved in 2014. The new variety, Y Liangyou 900 (YLY900), created a new yield record of 15.4 t/ha, which doubled the average rice yield in China. Up to now, 125 super rice varieties have been certificated by the Ministry of Agriculture with a total planting area of approximate 80 million hectare in China. However, how to further break the yield ceiling and realize the yield potential of elite varieties in diverse range of target environments remains to be the major challenges for super hybrid rice breeding. Herein, we proposed that utilization of ideotype and inter-subspecific heterosis, assisted with molecular design breeding, is still being the vital way to increase yield ceiling.