Response of rice yield, grain quality to chilling at grain filling stages.

BACKGROUND: This study aims to quantify the impacts of chilling at the grain filling stage on rice yield and grain quality. A factorial experiment with four levels of temperature and duration of chilling treatments at the early and late grain filling stages was conducted in 2017, 2018 and 2019. RESULTS: Per 10 °C·day increase in the accumulated cooling degree day at the early and late grain filling stages, the rice emergence-maturity duration was delayed by 0.8% (0.6%) and rice yield decreased by 2.2% (1.7%). Chilling at the early grain filling stage decreased the rice heading rate, while chilling at the late grain filling stage increased rice amylose but decreased protein content. For chilling treatment at the early grain filling stage, rice yield and grain quality were mainly correlated with seed-setting rate, whereas for chilling treatment at the late grain filling stage the rice yield and grain quality were mainly correlated with 1000-grain weight. CONCLUSION: This study improved the understanding of how chilling at the grain filling stages affects rice phenology, yield and grain quality, providing a theoretical basis for maintaining rice yield while ensuring grain quality. The results could be used to guide the rice-growing community in combating chilling at grain filling stages. © 2024 Society of Chemical Industry.

Adaptation measures of the potential double cropping region in Northern China to future climate change.

In the context of climate change, the northern climate-based boundaries of the winter wheat-summer maize double cropping system (DCS) have moved northward and westward. The selection of spring maize single cropping system (SCS) or DCS in the potential DCS region in northern China directly affects the annual crop yield, resource use efficiency, and greenhouse gas (GHG) emissions. Reducing GHG emissions while improving yield and resource use efficiency is essential to green agricultural development. We used future climate data (2021-2060, SSP2-4.5 and SSP5-8.5), along with crop and soil data, to assess the applicability of the Denitrification-Decomposition Model (DNDC) for simulating crop yield and GHG emissions. Through simulation of DNDC, we identified a cropping system that prioritized high yield, resource use efficiency, and GHG emissions reduction, adapting to future climate change. Under this cropping system, we quantified the effects of various straw incorporation rates, irrigation, and nitrogen input on crop yield, resource use efficiency, and GHG emissions. We proposed optimal measures to adapt to future climate change while aiming for high yield, resource use efficiency, and GHG emissions reduction. The results show that the DNDC reliably simulated yield and GHG emissions for the (SCS) and the DCS. In counting for greenhouse gas emission intensity (GHGI) as GHG emissions normalized by crop yield, the GHGI was reduced by 86.4% and 89.2% in DCS than in SCS under the SSP2-4.5 and SSP5-8.5, respectively. In the study area, the DCS should be adopted for high yield, resource use efficiency, and GHG emissions reduction (increased by 28.4% and 34.4%) in the SSP2-4.5 and SSP5-8.5 with 1) straw incorporation rate for 100% of winter wheat and for 60% of summer maize; 2) total irrigating 240 mm for winter wheat at pre-sowing, jointing, booting, and filling stages; and 3) applying nitrogen of 168 kg·N/ha for both crops.

Potential benefits of cropping pattern change in the climate-sensitive regions of rice production in China.

Rice production is a primary contributor to global greenhouse gas emissions, with unclear pathways towards carbon neutrality. Here, through a comprehensive assessment of direct greenhouse gas (GHG) emission using DNDC model and indirect GHG emission using emission factor methods, we estimated the annual crop yield, GHG emission amount and intensity, and economic benefits of different cropping patterns in the climate-sensitive regions of rice production in China. Through the expansion of single-rice and cropping pattern change from the wheat-rice to wheat-rice-rice in the climate-sensitive regions of single and triple-cropping cultivations, the total grain yield increased by 4.4 % and 4.5 % compared with the current national grain production, the GHG emission would increase by 2.4 % and 5.4 % of the current national GHG emissions from rice and wheat production, the net economic benefits could increase 0.9 % and decrease 2.0 % of the national output value of rice and wheat production. The study takes the entire-life cycle of crop growth as the principal line, and could provide a valuable reference for the regulation of the cropping pattern and the formulation of carbon reduction policies in the climate-sensitive region.

[Spatial-temporal characteristics of agricultural climate resources and sterile-type chilling injury in rice growing season in three provinces of Northeast China]. / 东北三省水稻生长季农业气候资源及障碍型冷害的时空特征.

Based on daily meteorological data and agro-meteorological data in three provinces of Northeast China during 1981-2017, combined with chilling injury indices, we analyzed the spatial-temporal distribution characteristics of solar, heat, precipitation resources and sterile-type chilling injury in rice growing season, especially in the booting and flowering stages. In 1981-2017, agriculture climatic resources in rice growing season showed a warming, drying and darkening trend. Accumulated temperature (≥10 ℃) and sunshine hours increased with a rate of 73.5 ℃·d·(10 a)-1 and 17.7 h·(10 a)-1 respectively, while precipitation decreased with a rate of 8.9 mm·(10 a)-1. At the booting stage, agricultural climatic resources showed a warming, drying and dar-kening trend. Daily average temperature increased 0.27 ℃·(10 a)-1 and sunshine hours and preci-pitation decreased 2.06 h·(10 a)-1 and 1.90 mm·(10 a)-1 respectively. At the flowering stage, agricultural climatic resources showed a trend of warming, wetting and darkening. Daily average temperature increased with a rate of 0.12 ℃·(10 a)-1, while sunshine hours decreased with a rate of 0.83 h·(10 a)-1. In contrast to that at the booting stage, precipitation in the flowering stage increased with a rate of 1.35 mm·(10 a)-1. Under the background of climate warming, the frequency and intensity of rice sterile-type chil-ling injury decreased in most regions, with significant inter-decadal fluctuations. During the study period, the frequency and intensity of sterile-type chil-ling injury were the highest in Heilongjiang Province, moderate in Jilin Province, and the lowest in Liaoning Province.

[Clinical therapeutic effect on bronchial asthma in children of different body constitutions treated with sanfu pingchuan plaster and sanjiu zhichuan plaster].

OBJECTIVE: To observe the difference in the clinical therapeutic effects on bronchial asthma in children of different body constitutions treated with sanfu pingchuan plaster and sanjiu zhichuan plaster. METHODS: One hundred and twenty-two children of bronchial asthma were divided into three groups according to TCM body constitutions, 42 cases in the qi deficiency constitution group, 40 cases in the yang deficiency constitution group and 40 cases in the phlegm damp constitution group. From 2011 to 2013, the acupoint plaster was applied to all of the children in the three groups during the dog days and the third nine-day period after the winter solstice each year. The average attack frequency and onset days of bronchial asthma and relevant immune function indicators were observed during treatment and 1 year after treatment in the children and the therapeutic effects were evaluated. RESULTS: ①In 2014, the acute attacks of bronchial asthma were (1.2±0.9) times and (1.4±0.4) times in the qi deficiency constitution group and the yang deficiency constitution group, all lower than (3.0±0.5) times in the phlegm damp constitution group (both P<0.05) separately. ②After treatment, in the qi deficiency constitution group and yang deficiency constitution group, the values of IgG, IgA and IgM were all increased as compared with those before treatment (all P<0.05). ③The total effective rate was over 95% in the children of the three groups. The clinical control rates in the qi deficiency constitution group and the yang deficiency constitution group were higher apparently than that in the phlegm damp constitution group, indicating the significant difference statistically (both P<0.05). CONCLUSIONS: The combined treatment of sanfu pingchuan plaster and sanjiu zhichuan plaster are effective on bronchial asthma in the children of different body constitutions. The therapeutic effects for the qi deficiency constitution and the yang deficiency constitution are more apparent than that for the phlegm damp constitution.