The Possible Effect of Climate Warming on Northern Limits of Cropping System and Crop Yield in China

Significantly increasing temperature since the 1980s in China has become a consensus under the background of global climate change and how climate change affects agriculture or even cropping systems has attracted more and more attention from Chinese government and scientists. In this study, the possible effects of climate warming on the national northern limits of cropping systems, the northern limits of winter wheat and double rice, and the stable-yield northern limits of rainfed winter wheat-summer maize rotation in China from 1981 to 2007 were analyzed. Also, the possible change of crop yield caused by planting limits displacement during the periods 1950s-1981 and 1981-2007 was compared and discussed. The recognized calculation methods of agricultural climatic indices were employed. According to the indices of climatic regionalization for cropping systems, the national northern limits of cropping systems, winter wheat and double rice, and the stable-yield northern limits of rainfed winter wheat-summer maize rotation during two periods, including the 1950s-1980 and 1981-2007, were drawn with ArcGIS software. Compared with the situation during the 1950s- 1980, the northern limits of double cropping system during 1981-2007 showed significant spatial displacement in Shaanxi, Shanxi, Hebei, and Liaoning provinces and Beijing municipality, China. The northern limits of triple cropping system showed the maximum spatial displacement in Hunan, Hubei, Anhui, Jiangsu, and Zhejiang provinces, China. Without considering variety change and social economic factors, the per unit area grain yield of main planting patterns would increase about 54-106% if single cropping system was replaced by double cropping system, which turned out to be 27- 58% if double cropping system was replaced by triple cropping system. In Liaoning, Hebei, Shanxi, Shaanxi, Gansu, and Qinghai provinces, Inner Mongolia and Ningxia autonomous regions, China, the northern limits of winter wheat during 1981-2007 moved northward and expanded westward in different degrees, compared with those during the 1950s-1980. Taking Hebei Province as an example, the northern limits of winter wheat moved northward, and the per unit area grain yield would averagely increase about 25% in the change region if the spring wheat was replaced by winter wheat. In Zhejiang, Anhui, Hubei, and Hunan provinces, China, the planting northern limits of double rice moved northward, and the per unit area grain yield would increase in different degrees only from the perspective of heat resource. The stable- yield northern limits of rainfed winter wheat-summer maize rotation moved southeastward in most regions, which was caused by the decrease of local precipitation in recent years. During the past 50 yr, climate warming made the national northern limits of cropping systems move northward in different degrees, the northern limits of winter wheat and double rice both moved northward, and the cropping system change would cause the increase of per unit area grain yield in the change region. However, the stable-yield northern limits of rainfed winter wheat-summer maize rotation moved southeastward due to the decrease of precipitation.

Integrating remotely sensed water stress factor with a crop growth model for winter wheat yield estimation in the North China Plain during 2008–2018

Accurate estimation of regional-scale crop yield under drought conditions allows farmers and agricultural agencies to make well-informed decisions and guide agronomic management. However, few studies have focused on using the crop model data assimilation(CMDA) method for regional-scale winter wheat yield estimation under drought stress and partial-irrigation conditions. In this study, we developed a CMDA framework to integrate remotely sensed water stress factor(MOD16 ET PET) with the WOFOST model using an ensemble Kalman filter(En KF) for winter wheat yield estimation at the regional scale in the North China Plain(NCP) during 2008–2018. According to our results, integration of MOD16 ET PETwith the WOFOST model produced more accurate estimates of regional winter wheat yield than open-loop simulation. The correlation coefficient of simulated yield with statistical yield increased for each year and error decreased in most years, with r ranging from 0.28 to 0.65 and RMSE ranging from 700.08 to1966.12 kg ha. Yield estimation using the CMDA method was more suitable in drought years(r = 0.47, RMSE = 919.04 kg ha) than in normal years(r = 0.30, RMSE = 1215.51 kg ha). Our approach performed better in yield estimation under drought conditions than the conventional empirical correlation method using vegetation condition index(VCI). This research highlighted the potential of assimilating remotely sensed water stress factor, which can account for irrigation benefit, into crop model for improving the accuracy of winter wheat yield estimation at the regional scale especially under drought conditions, and this approach can be easily adapted to other regions and crops.

Numerous experiments for the impact of warming climate on the phenology and grain yield of winter wheat

Based on the environmental and crop data at Zhenjiang City, in Jiangsu Province, middle east of China, the growing process of winter wheat was simulated by CERES-Wheat model assuming the daily average temperature is 1℃ to 2℃ higher than at the present, which are mostly possible for the change of climate because of enrichment of greenhouse gases in the atmosphere. The simulation results show that warming climate can promote development rate and shorten phenological stages of wheat, and the grain yield will be higher than present. Its impact on the kernel weight and grains per square meter were different for the plantings of various sowing dates. The results of this study suggest that substantial changes in agricultural production and management practices are needed to respond to the climatic changes expected to take place in China.

Comparison of winter wheat yield sensitivity to climate variables under irrigated and rain-fed conditions

Crop simulation models provide alternative, less time-consuming, and cost-effective means of deter- mining the sensitivity of crop yield to climate change. In this study, two dynamic mechanistic models, CERES （Crop Environment Resource Synthesis） and APSIM （Agricultural Production Systems Simulator）, were used to simulate the yield of wheat （Triticum aestivum L.） under well irrigated （CFG） and rain-fed （YY） conditions in relation to different climate variables in the North China Plain （NCP）. The study tested winter wheat yield sensitivity to different levels of temperature, radiation, precipitation, and atmospheric carbon dioxide （COa） concentration under CFG and YY conditions at Luancheng Agro-ecosystem Experimental Stations in the NCR The results from the CERES and APSIM wheat crop models were largely consistent and suggested that changes in climate variables influenced wheat grain yield in the NCR There was also significant variation in the sensitivity of winter wheat yield to climate variables under different water （CFG and YY） conditions. While a temperature increase of 2℃ was the threshold beyond which temperature negatively influenced wheat yield under CFG, a temperature rise exceeding 1℃ decreased winter wheat grain yield under YY. A decrease in solar radiation decreased wheat grain yield under both CFG and YY conditions. Although the sensitivity of winter wheat yield to precipitation was small under the CFG, yield decreased significantly with decreasing precipitation under the rain- fed YY treatment. The results also suggest that wheat yield under CFG linearly increased by ≈ 3.5% per 60 ppm （parts per million） increase in CO2 concentration from 380 to560ppm, and yield under YY increased linearly by ≈ 7.0% for the same increase in CO2 concentration.

Responses of Irrigated Winter Wheat Yield in North China to Increased Temperature and Elevated CO2Concentration

North China is one of the main regions of irrigated winter wheat production in China. Climate warming is apparent in this region, especially during the growing season of winter wheat. To understand how the yield of irrigated winter wheat in North China might be affected by climate warming and CO2 concentration enrichment in future, a set of manipulative field experiments was conducted in a site in the North China Plain under increased temperature and elevated CO2 concentration by using open top chambers and infrared radiator heaters. The results indicated that an average temperature increase of 1.7℃ in the growing season with CO2 concentration of 560 μmol mol-1 did not reduce the yield of irrigated winter wheat. The thousand- kernel weight of winter wheat did not change significantly despite improvement in the filling rate, because the increased temperature shortened the duration of grain filling. The number of effective panicles and the grain number per ear of winter wheat did not show significant changes. There was a large increase in the shoot biomass because of the increase in stem number and plant height. Consequently, under the prescribed scenario of asymmetric temperature increases and elevated CO2 concentration, the yield of irrigated winter wheat in North China is not likely to change significantly, but the harvest index of winter wheat is likely to be greatly reduced.

Impacts of Nighttime Warming on the Soil Nematode Community in a Winter Wheat Field of Yangtze Delta Plain, China

Changes in the soil nematode community induced by global warming may have a considerable influence on agro-ecosystem functioning. However, the impacts of predicted warming on nematode community in farmland （e.g., winter wheat field） have not been well documented. Therefore, a field experiment with free air temperature increase （FATI） was conducted to investigate the responses of the soil nematode community to nighttime warming in a winter wheat field of Yangtze Delta Plain, China, during 2007 to 2009. Nighttime warming （NW） by 1.8~C at 5-cm soil depth had no significant impact on the total nematode abundance compared to un-warmed control （CK）. However, NW significantly affected the nematode community structure. Warming favored the bacterivores and fungivores, such as Acrobeles, Monhystera, Rhabditis, and Rhabdontolaimus in bacterivores, and Filenchus in fungivores, while the plant-parasites were hindered, such as Helicotylenchus and Psilenchus. Interestingly, the carnivores/ omnivores remained almost unchanged. Hence, the abundances ofbacterivores and fungivores were significantly higher under NW than those under CK. Similarly, the abundances of plant-parasites were significantly lower under NW than under CK. Furthermore, Wasilewska index of the nematode community was significantly higher under NW than those under CK, indicating beneficial effect to the plant in the soil. Our results suggest that nighttime warming may improve soil fertility and decrease soil- borne diseases in winter wheat field through affecting the soil nematode community. It is also indicated that nighttime warming may promote the sustainability of the nematode community by altering genera-specific habitat suitability for soil biota.

Fields experiments in North China show no decrease in winter wheat yields with night temperature increased by 2.0-2.5°C

The trends of daily maximum and minimum temperature in global warming indicated that the daily minimum temperature （Tmin） has risen more than twice as fast as the daily maximum temperature （Tmax） during the 20th century. Most researchers have focused on how the crops respond to daily mean temperature, whereas few controlled experiments were carried out to in- vestigate how the crops respond to the Train rise. In particular, no experiment research has reported on how crops respond to the higher night temperature, which was the main trend in the climate warming. Taking winter wheat as the test crop, we investi- gated how the winter wheat growth and yields responded to the higher night temperature. In the field experiments, infrared heaters were used to increase higher night temperature （HNT） by about 2.5℃ in contrast to the normal night temperature （CK） in two whole growth durations of winter wheat in 2008-2009 and 2009-2010 in North China. The results indicated that, com- pared to the CK treatment, winter wheat yield did not decline in HNT treatment, which increased temperatures by 2.0-2.5℃ in both Wanner year （WY） and Colder year （CY）. Furthermore, winter wheat yield in CY increased significantly in HNT treatment. HNT treatment in CY could significantly promote tillering and increase the effective panicles, which increased grain yield significantly （by more than 30% compared with CK）. HNT treatment in CY contributed to an increase in the effective panicles and Kernels significantly, although making a significant reduction in 1000-grain weight, but did not lead to the yield decline. Under the HNT treatment, the whole growth duration of the winter wheat was shortened and the phenological dates were earlier except for the beginning of overwintering; the beginnings of the overwintering phase were postponed substantially and the ends of the overwintering phase were ahead of date compared to CK, which shortened the duration of overwintering considerably. We draw on our own studies to show examples of higher night temperature impact on winter wheat in a relative- ly cold year and relatively warm year in North China. Our results refer to winter wheat in North China, not all main winter wheat producing regions, in Huang-Huai and Southwest of China. Some uncertainties of our predictions derive from fast pro- gress in crop breeding, the variability of climate, and the role of adaptive actions in the future. As expected, the adaptation measures should be considered to cope with the impacts of global warming on crops, and further research and assessments should be conducted.

The Influence of Climate Change on Winter Wheat during 2012-2100 under A2 and A1B Scenarios in China

By assuming constant winter wheat varieties and agricultural practices in China, the influence of climate change on winter wheat is simulated using the corrected future climate projections under SRES A2 and A1B scenarios from 2012 to 2100, respectively. The results indicate that the growth of winter wheat would be strongly influenced by climate change in future. The average flowering and maturity dates of winter wheat would advance by 26 and 27 days under scenario A2, and by 23 and 24 days respectively under scenario A1B from 2012 to 2100. The simulated potential productivity of winter wheat shows a decrease of 14.3% and 12.5% for scenarios A2 and A1B respectively without the fertilization effect of CO2, while an increase of 1.3% and 0.6% with the fertilization effect of CO2. Additionally, for northern China, the simulated potential productivity would markedly decrease under both scenarios, independent with the fertilization effect of CO2, which indicates that the current planted winter wheat would be more vulnerable than that in southern China. The most likely reason is the current winter wheat varieties in northern China are winter varieties or strong winter varieties, which need some days of low temperature for dormancy. While in southern China, the winter wheat is spring or half winter varieties and can grow slowly during winter, thus, they would be affected slightly when winter temperature increases. The results of this study may have important implications for adaptation measures.

Response to climate warming of winter wheat varieties bred across different eras in the North China Plain

By the 2000s,the winter wheat regions in the North China Plain had undergone six major variety renewals.It is crucial to know how the winter wheat varieties bred across different eras respond to climate change,especially climate warming.From 2017 to 2022,we conducted a two-factor,two-level field experiment at Gucheng and Raoyang,with a temperature difference of 1℃existing between the two sites.The experiment used ten winter wheat varieties bred from the 1960s to the 2000s and included both fertilization and no fertilization treatments.The experiment aimed to separate the effects of warming and fertilization on the growth and development of the winter wheat varieties,thereby revealing the differences in their responses to warming.All the winter wheat varieties across different eras had higher yields in warmer environments.By separating the effects of warming and fertilization,the rate of yield increase decreased with the breeding eras of varieties due to the impact of warming alone.However,it still increased with the eras due to the combined effects of warming and fertilization.For varieties from the 1980s and 2000s,there is a strong correlation between higher fertility and warmer climate adaptability.Warming has a yield gain effect,significantly amplifying the yield increase under fertilization for the middle and late varieties.Therefore,the average yield increase for varieties from the 2000s reached 67%in warmer environments.Warming has increased the average daily minimum temperature during the winter wheat growing season.It has significantly reduced the number of days below zero degrees Celsius,shortening the overwintering stage and thereby shortening the growth period of winter wheat.However,the effective developmental days(>0℃days)maintained a consistent level.Warming promotes the development of large tillers,increases leaf area and dry matter accumulation,and reduces the ratio of sterile spikelets.The varieties from the 2000s had the lowest ratio of sterile spikelets and the highest harvest index(HI)in warmer environments,resulting in a significant increase in yield.This study reveals the differential responses to the warming of winter wheat varieties across different eras,which have a specific reference for winter wheat breeding to cope with climate change.

Composite Simulation of Dynamic Water Content and Water Use Efficiency of Winter Wheat

In order to forecast the effect of climate warming on agriculture,ENWATBAL model was used to simulate evapotranspiration of winter wheat due to the change of air temperature and precipitation in the coming decades.The effect of climate warming on winter wheat yield in the future decades was speculated by the past yield and climate data in last decades,and the possible water use efficiency in the future decades was calculated.The results indicate that climate warming would increase winter wheat evapotranspiration,and decrease yield and water use efficiency of winter wheat.It shows that climate warming would intensify the water shortage in agriculture,and it is necessary to develop watersaving agriculture.

Effects of warming and drought stress on the growth characteristics,photosynthetic-transpiration rates,and yield of winter wheat

Climate change has limited crop productivity worldwide.Understanding crop response to global climate changes is vital to maintaining agricultural sustainable development.A two-year experiment was conducted to investigate the effects of warming and drought on crop growth and winter wheat yield production.The results showed that both warming and drought shortened the crop growth period,reduced the leaf area index,and increased winter wheat biomass accumulation.Under sufficient water supply conditions,warming would increase photosynthetic and transpiration rates and water use efficiency,while under water deficit conditions,the opposite was observed.Under warming conditions,the grain yield of the water deficit treatment was 8.9%lower than that of the sufficient water supply treatment.Under non-warming conditions,the grain yield of water deficit treatment was 12.4%lower than that of the sufficient water supply.Under the conditions of water-sufficient supply,the grain yield of the warming treatment was 4.4%lower than that of the non-warming treatment,and under the conditions of water deficit,the grain yield of the warming treatment was 1.3%lower than that of the non-warming treatment.Warming tends to decrease wheat growth and grain yield,but sufficient water supply could improve winter wheat’s water use efficiency and reduce the warming limitation on wheat production.

基于遥感信息和WOFOST模型参数同化的冬小麦单产估算方法研究

为探讨遥感信息和作物生长模型在作物估产方面的优势互补特性,选取河北省藁城市冬小麦作为研究对象,采集多个关键生育时期的生理生化、农田环境、气象等数据,并获取准同步的环境减灾小卫星HJ-CCD影像数据,采用植被指数反演冬小麦叶面积指数(LAI),基于扩展傅里叶振幅灵敏度检验法(EFAST)对WOFOST作物模型的26个初始参数进行全局敏感性分析,筛选敏感性参数,调整WOFOST模型的核心参数,利用查找表优化算法构建基于WOFOST模型和遥感LAI数据同化的区域尺度冬小麦单产预测模型,并定量预测区域冬小麦单产水平。结果表明,增强型植被指数(EVI)是遥感反演LAI的最佳植被指数(开花期建模r^2=0.913,RMSE=0.410,灌浆期建模r^2=0.798,RMSE=0.470),预测能力最强(开花期r^2=0.858,RMSE=0.531,灌浆期r2=0.861,RMSE=0.428);筛选出6个待优化参数,即TSUM1、SLATB1、SLATB2、SPAN、EFFTB3和TMPF4;产量预测精度r^2=0.914,RMSE=253.67kg·hm^(-2),找到了待优化参数的最佳取值,最终完成了单产模拟。

基于WOFOST模型的江苏冬小麦生长模拟

WOFOST模型是目前常用的作物模型之一。采用2015-2017年区域气象站点的气象数据、土壤数据、作物数据等,利用OAT方法进行模型参数敏感性分析,结合最小二乘法、"试错法"等,并借鉴前人研究结果,基于不同密度和氮肥处理水平,针对冬小麦发育参数出苗到开花积温(TSUM1)、开花到成熟积温(TSUM2)以及生长参数比叶面积(SLATB)、最大CO2同化速率(AMAXTB)进行冬小麦参数调整,实现WOFOST模型本地化。结果表明:WOFOST模型模拟冬小麦LAI的R2、RMSE、NRMSE分别为0.817 8、0.58、27.9%,模拟叶、茎、穗和地上部总生物量的R2、RMSE、NRMSE分别为0.783 2~0.953 1、315.55~986.15 kg·hm^-2、10.1%~29.8%,模拟产量的R2、RMSE、NRMSE分别为0.585 2、799.96kg·hm^-2、15.9%,与实测值均有较好的一致性。这一研究说明WOFOST模型能较好地模拟研究区域冬小麦的生长发育状况。

基于WOFOST模型的河北省保定市冬小麦最佳灌溉方案研究

利用WOFOST模型对保定地区冬小麦不同年型灌溉方案进行模拟分析,确定最佳灌溉量及灌溉时间,力争灌溉效益最大化,对缓解农业生产和水资源匮乏的尖锐矛盾尤显重要。文章以河北省保定市为例,应用WO)FOST模型对不同降水年型的2003/2004、2005/2006和2008/2009年3个代表生长季,分别进行一次灌溉、两次灌溉、三次灌溉的不同灌溉方案进行模拟,试图揭示冬小麦产量随灌溉时间及灌溉量的变化规律,选择最佳灌溉方案,为干旱缺水的河北省保定市小麦节水、高产提供理论依据。模拟研究结果表明:在冬小麦全生育期中最佳灌溉时期为拔节—孕穗期和抽穗—灌浆期,这两个时期的灌溉对产量的贡献率最高。与此同时,总结出了既可以满足冬小麦生长又可以获得较大经济效益的两次灌溉及三次灌溉的最佳灌溉方案。

Impact of thermal time shift on wheat phenology and yield under warming climate in the Huang-Huai-Hai Plain, China

Given climate change can potentially influence crop phenology and subsequent yield, an investigation of relevant adaptation measures could increase the understanding and mitigation of these responses in the future. In this study, field observations at 10 stations in the Huang- Huai-Hai Plain of China （HHHP） are used in combination with the Agricultural Production Systems Simulator （APSIM）-Wheat model to determine the effect of thermal time shift on the phenology and potential yield of wheat from 1981-2009. Warming climate speeds up winter wheat development and thereby decreases the duration of the wheat growth period. However, APSIM-Wheat model simulation suggests prolongation of the period from flowering to maturity （Gr） of winter wheat by 0.2-0.8 d·10yr^-1 as the number of days by which maturity advances, which is less than that by which flowering advances. Based on computed thermal time of the two critical growth phases of wheat, total thermal time from floral initiation to flowering （TT_floral_initiation） increasesd in seven out of the 10 investigated stations. Altematively, total thermal time from the start of grainfilling to maturity （TT_start grain_fill） increased in all investigated stations, except Laiyang. It is thus concluded that thermal time shift during the past three decades （1981- 2009） prolongs Gr by 0.2-3.0 d·10yr^-1 in the study area. This suggests that an increase in thermal time （TT） of the wheat growth period is critical for mitigating the effect of growth period reduction due to warming climatic condition. Furthermore, climate change reduces potential yield of winter wheat in 80% of the stations by 2.3-58.8 kg·yr^-1. However, thermal time shift （TTS） increases potential yield of winter wheat in most of the stations by 3.0-51.0 Received September 16, 2015; accepted January 24, 2016 kg·yr^-1. It is concluded that wheat cultivars with longer growth periods and higher thermal requirements could mitigate the negative effects of warming climate on crop production in the study area.

基于WOFOST模型的冬小麦产量动态预报方法

为了确定基于WOFOST作物模型的冬小麦产量动态预报方法及产量预报业务应用效果,利用全国冬小麦主产区内174个农业气象站冬小麦生育期、叶面积指数和土壤湿度等观测资料以及15个农业气象试验站冬小麦生物量观测资料,完成WOFOST冬小麦模型参数本地化和区域化。利用全国冬小麦主产区约1200个气象观测站起报日前的逐日气象资料及起报日后30 a平均气候值组成的冬小麦全生育期气象数据驱动模型,模拟得到冬小麦地上总生物量和穗干重,站点和县级尺度的冬小麦单产直接采用穗干重来进行产量预报,省级和全国区域冬小麦平均单产根据模拟值2 a间的变化幅度进行产量预报。根据不同空间尺度的历史年预报冬小麦单产与实际产量数据的对比,进行基于WOFOST模型的冬小麦产量预报方法效果检验。结果表明:(1)2014—2019年期间295个农业气象站次冬小麦产量估测平均准确率为81.8%,220个次县冬小麦单产估测平均准确率为84.3%,预报结果具有可用性;(2)12个主产省(市、区)冬小麦单产2003—2019年平均预报准确率为88.2%~96.4%,全国冬小麦单产预报准确率为93.9%~95.9%,总体预报准确率较高,说明基于WOFOST模型的冬小麦产量动态预报方法具有可行性;(3)基于WOFOST模型与统计方法的冬小麦平均单产估产结果准确率略偏低,但预报的时效性和动态性具有更好的优势,能满足作物产量预报业务需求。基于WOFOST模型的不同空间尺度冬小麦单产动态产量估测的准确率验证,说明WOFOST在作物产量预报业务应用具有可行性;利用作物模型进行基于站点尺度的产量预报能够提高作物产量预报时空精细化能力,也能扩展到大尺度区域应用以达到对农业决策和宏观调控的目的。

利用WOFOST作物模型研究气候变暖对冬小麦产量的影响

全球气候变暖已经成为一个不争的事实，开展气候变化对冬小麦产量影响的数值模拟对制定农业政策以适应气候变化具有重要意义。本文使用荷兰瓦赫宁根大学开发的WOFOST模型，利用太谷2000年和2001年的数据对WOFOST模型进行验证，确定该模型在山西太谷地区的适用性。文章分析了太谷地区气温变化趋势，假定以1985年-2007年的变暖趋势增温，假设其它条件不变，从而构建了100年内每10a的时间间隔的气象情形。以这些气象情形驱动验证好的模型模拟100年内每10a的时间间隔气候变暖对冬小麦产量的影响。模拟结果表明，气温变化对冬小麦产量的影响不是单一的，未来冬小麦的产量是波动变化的。

湖北省小麦潜在产量时空异质性特征及驱动因子分析

气候变化致使气象要素的时空分布格局发生了不同程度的变化,加剧了作物产量空间异质性的形成。因此,评估气候因子对潜在产量的贡献程度,有利于解析区域间潜在产量差异的形成机制,这对于区域内作物的合理规划和缩小区域间产量差具有重要意义。本研究基于1985—2021年湖北省小麦生长期间的气候数据,应用验证后的APSIM-Wheat模型模拟小麦的潜在产量,利用多元回归等方法评估各气候因子对潜在产量变化的贡献程度,解析潜在产量空间异质性的形成机制。结果表明:湖北省小麦潜在产量变化范围为5068.9~7895.3 kg∙hm^(−2),平均潜在产量为7187.6 kg∙hm^(−2)。近35年来,小麦生育期内的平均温度和总降水量分别以0.1℃∙(10a)−1和13.2 mm∙(10a)−1的速率增加,但总太阳辐射以123.3 MJ∙m^(−2)∙(10a)^(−1)的速率下降。这些气候因素变化加剧了生育期内易涝、弱光环境的形成,导致小麦生产潜力降低,潜在产量平均每10年下降422.0 kg∙hm^(−2),降水量的增加对潜在产量下降的贡献最大,相关系数高达−0.73。湖北省小麦潜在产量的空间分布特征为北高南低,南北小麦平均潜在产量和光热熵差距分别为218 kg∙hm^(−2)和0.06 MJ∙m^(−2)∙d^(−1)∙℃^(−1)。光热熵的高度空间异质性是造成潜在产量差异的主要因素,二者相关性高达0.82。受光热熵时空分布不均的影响,荆州小麦拔节至成熟期的平均每日生长速率较襄阳地区低28.5 kg∙hm^(−2)∙d^(−1),最终导致荆州小麦的潜在产量较襄阳地区低。综上,气候变化使得湖北省小麦潜在产量整体呈下降趋势,针对以江汉平原地区为代表的易涝、弱光的小麦生长环境,选育具有高光效和耐涝性的小麦品种对于缩小区域间的产量差距和实现区域粮食总产的全面提高具有重要意义。

灌浆期开放式增温对不同小麦产量和品质的影响

为研究灌浆期开放条件下增温对不同小麦产量及品质的影响,采用开放式红外增温技术,以‘济麦22’和‘济麦44’为材料,于2020—2022年进行灌浆期白天增温来模拟未来气候变暖下温度升高对不同小麦产量及其构成因素和品质(主要是淀粉和蛋白质)的影响。在本试验条件下,增温处理的两种小麦千粒质量和产量均呈现下降趋势,千粒质量下降3.3%~5.7%,产量损失2.0%~5.0%。增温使两个品种的淀粉含量降低1.4%~2.4%,白度降低1.6%~1.8%,面筋指数降低0.4%~3.6%。灌浆期增温处理增加了小麦籽粒蛋白含量,增幅为1.1%~9.6%,沉降值增加0.8%~11.9%。另外增温处理对两种小麦面粉的淀粉糊化特性产生了不同的影响,‘济麦22’面粉的低谷黏度和峰值黏度显著上升,最终黏度、回生值和糊化温度差异不显著;‘济麦44’面粉的低谷黏度、峰值黏度和最终黏度显著下降,回生值和糊化温度差异不显著。综上,在其他生育进程不变的情况下,灌浆期增温将会导致小麦减产,同时小麦籽粒物质组成也将发生复杂的变化,从而影响到小麦的品质。

增温背景下不同土壤对冬小麦产量品质影响评价

利用冬小麦品种‘镇麦168’,以黄棕壤、砂礓黑土、风沙土、红壤、潮土、黑土、黄土、灰钙土、紫色土、砖红壤、盐碱土和棕壤共12种典型农田土壤为基质,在开放式增温系统开展模拟大气增温框栽试验。试验设置常温对照(CK)和增温1.5℃(eT)两个处理,增温处理为冬小麦全生育期增温。以成熟期冬小麦单穗粒数、千粒重等表征产量变化,籽粒淀粉、蛋白质及其组分等营养指标体现品质构成。结果表明:(1)全生育期增温分别使黄棕壤、风沙土、黑土、黄土、灰钙土和紫色土冬小麦较常温对照减产33.82%、20.96%、16.60%、55.92%、28.45%和21.19%,但潮土冬小麦增产16.13%(P<0.05),其他土壤条件下冬小麦产量无明显变化。(2)就冬小麦营养品质,直链淀粉和支链淀粉含量在增温作用下较常温对照存在不同程度下降,且直链淀粉降幅大于支链淀粉,在红壤、黑土、黄土、灰钙土、紫色土、盐碱土和棕壤条件下冬小麦总淀粉含量显著降低(P<0.05)。籽粒蛋白质及其组分,清蛋白和球蛋白呈显著增加趋势,而醇溶蛋白和谷蛋白显著下降,且降幅大于前两者增幅,除红壤冬小麦总蛋白含量无显著变化以外,其他11种土壤条件下冬小麦总蛋白含量均较常温对照显著降低(P<0.05)。冬小麦可溶性总糖仅在潮土、灰钙土和紫色土条件下显示出显著增加趋势(P<0.05)。(3)利用隶属函数对常温对照和增温各处理进行综合品质排名,表现最好的为常温组黑土冬小麦(U=0.707),常温组中棕壤(U=0.691)、灰钙土(U=0.647)、紫色土(U=0.644)和黄土冬小麦(U=0.644)次之,品质最差的是常温下红壤冬小麦(U=0.364)和增温下红壤冬小麦(U=0.368)。除潮土冬小麦以外,其他11种土壤冬小麦品质均表现为增温劣于对照。(4)常温条件下冬小麦产量最大影响因素为单穗粒数,直接通径系数为0.630,其次为有效穗数和球蛋白,均体现为直接作用,直接通径系数分别为0.538和-0.118;增温条件下冬小麦产量最大影响因素也是单穗粒数,直接通径系数为0.603,其次为有效穗数、千粒重和总淀粉,有效穗数和总淀粉通过与单穗粒数的间接作用对冬小麦产量产生影响,间接通径系数分别为0.322和0.381。综合而言,增温通过对冬小麦产量构成和籽粒营养成分的综合作用影响品质,12种典型农田土壤中,潮土冬小麦对增温表现为正效应,其他土壤为负效应,冬小麦产量品质形成对气候变暖响应受到土壤类型的调控。