Global warming over 1960–2009 did increase heat stress and reduce cold stress in the major rice-planting areas across China

Increasing extreme temperature events have raised concerns regarding the risk of rice production to extreme temperature stress (ETS). However, across China what places were exposed to higher ETS during rice-growing period and how ETS has changed over the past five decades, remain unclear. Here, we first compared two indexes for characterizing ETS on rice crop, including Duration-based ETS index (DETS) and Growing Degree Days (GDD). Then, based on the better-performing index and an improved dataset of rice phenological records, we comprehensively assessed the spatio-temporal patterns of ETS at county scale in the major rice-planting areas across China during 1960–2009. The results showed that GDD had an advantage over DETS in characterizing ETS, due to fully consideration of both the specific intensity and duration of extreme temperature events. Based on GDD, we found that ETS on rice crops had significantly changed in both space and time over the last five decades. Spatially, single rice in Northeast China (Region I) and late rice in southern China (Region IV) saw high exposure to cold stress, especially during the heading-flowering stage. The hot spots of heat stress were found for single rice in the Yangtze River basin (Region III) (2.25 °C) during the booting stage, and for early rice in Region IV (4.42 °C) during the heading-flowering stage. During 1960–2009, global warming did increase heat stress (0.04 and 0.12 °C year⁻¹ for the stages of booting and heading-flowering, respectively) and reduce cold stress (−0.03 and −0.21 °C year⁻¹ for the stages of booting and heading-flowering, respectively) in the major rice-planting areas across China. Some particular areas, such as Yunan Province (P4) with increasing cold stress and Zhejiang Province (P13) with increasing heat stress, should be priorities for adaptations to cope with the rising risk of ETS under climate warming.     

饲养温度和饲喂方式对断奶仔猪消化酶活性和胃肠道pH的影响

试验选用21日龄杜长大断奶仔猪240头(6.38±0.35)kg,采用2×2因子设计,研究饲养温度和饲喂方式对断奶仔猪消化酶活性和胃肠道pH的影响。结果表明:高温处理组(28～30℃)饲养的仔猪肠道淀粉酶活性显著高于低温处理组(23～25℃)(P0.05)。高温处理组仔猪肠道pH显著低于低温处理组(P0.05)。定时饲喂饲养的仔猪肠道淀粉酶活性显著高于自由采食饲养的仔猪(P0.05)。从饲养温度和饲喂方式互作方面来看,高温自由采食组和高温定时饲喂组的肠道淀粉酶活性显著高于低温自由采食组和低温定时饲喂组(P0.01)。饲养温度对断奶仔猪消化酶活性和胃肠道pH有较大影响。高的饲养温度(28～30℃)有利于提高断奶仔猪体内消化酶活性和降低消化道酸度,增强仔猪的消化性能。     

Predominant bacterial and fungal assemblages in agricultural soils during a record drought/heat wave and linkages to enzyme activities of biogeochemical cycling

Identification of microbial assemblages predominant under natural extreme climatic events will aid in our understanding of the resilience and resistance of microbial communities to climate change. From November 2010 to August 2011, the Southern High Plains (SHP) of Texas, USA, received only 39.6 mm of precipitation (vs. the historical average of 373 mm) and experienced the three hottest months (June–August 2011) since record keeping began in 1911. The objective of this study was to characterize soil bacterial (16 S rRNA gene) and fungal (internal transcribed spacer 1–4, ITS1-ITS4) species distribution and diversity via pyrosequencing during the peak of the drought/heat wave in July 2011 and when the Drought Index and temperatures were lower in March 2012. Samples were collected from two different soil types (loam and sandy loam) under two different dryland cropping histories (monoculture vs. rotation). Fungal Diversity Indexes were significantly higher after the drought/heat wave while Bacterial Indexes were similar. Bacterial phyla distribution in July 2011 was characterized by lower relative abundance of Acidobacteriaand Verrucomicrobia, and greater relative abundance of Proteobacteria, Chloroflexi, Actinobacteria and Nitrospirae than March 2012 samples. Further grouping of pyrosequencing data revealed approximately equal relative proportions of Gram positive (G+) and Gram negative (G−) bacteria in July 2011, while G− bacteria predominated in March 2012. Fungal class Dothideomycetes was approximately two times greater in July 2011 than in March 2012, while the class Sordariomycetes and a group of unidentified OTUs from Ascomycota increased from July 2011 to March 2012. Microbial community composition was less influenced by management history than by the difference in climatic conditions between the sampling times. Correspondence analysis identified assemblages of fungal and bacterial taxa associated with greater enzyme activities (EAs) of C, N, or P cycling found during the drought/heat wave. Microbial assemblages associated with arylsulfatase activity (key to S cycling), which increased after the drought/heat wave, were identified (Streptomyces parvisporogenes, Terrimonas ferruginea and Syntrophobacter sp.) regardless of the soil and management history. The distinct microbial composition found in July 2011 may represent assemblages essential to maintaining ecosystem function during extreme drought and intense heat waves in semiarid agroecosystems.     

Biocrusts modulate warming and rainfall exclusion effects on soil respiration in a semi-arid grassland

Soil surface communities composed of cyanobacteria, algae, mosses, liverworts, fungi, bacteria and lichens (biocrusts) largely affect soil respiration in dryland ecosystems. Climate change is expected to have large effects on biocrusts and associated ecosystem processes. However, few studies so far have experimentally assessed how expected changes in temperature and rainfall will affect soil respiration in biocrust-dominated ecosystems. We evaluated the impacts of biocrust development, increased air temperature and decreased precipitation on soil respiration dynamics during dry (2009) and wet (2010) years, and investigated the relative importance of soil temperature and moisture as environmental drivers of soil respiration, in a semiarid grassland from central Spain. Soil respiration rates were significantly lower in the dry than in the wet year, regardless of biocrust cover. Warming increased soil respiration rates, but this response was only significant in biocrust-dominated areas (>50% biocrust cover). Warming also increased the temperature sensitivity (Q₁₀ values) of soil respiration in biocrust-dominated areas, particularly during the wet year. The combination of warming and rainfall exclusion had similar effects in low biocrust cover areas. Our results highlight the importance of biocrusts as a modulator of soil respiration responses to both warming and rainfall exclusion, and indicate that they must be explicitly considered when evaluating soil respiration responses to climate change in drylands.     

江苏沿海海水鱼类养殖气候适宜性分析

[目的]研究江苏沿海海水鱼类养殖的气候适宜性。[方法]采取海洋气象指标分析法。[结果]江苏沿海气候是能养殖鲈鱼等海水鱼类的,地区间气候适宜性有明显的差异。[结论]从气候相对适宜性看,江苏沿海养殖海水鱼类的优先顺序为连云港、南通、盐城;造成地区间鱼类养殖气候适宜性差异的主要因素是高温、低气压、强降水等灾害性天气。     

气候变化对黑龙江农业气象灾害的影响及对策

气候变暖、降水减少已经成为气候变化的主要特征。对黑龙江省穆棱市1958~2007年观测资料的统计分析表明:穆棱市气候发生了很大的变化,暖冬现象日趋明显,年降水量呈下降趋势,干旱、洪涝、霜冻害、冰雹、病虫害等农业气象灾害发生了相应的变化,主要表现在干旱、冰雹、病虫害等灾害增加,洪涝、霜冻害等灾害减少。针对气候变化对农业气象灾害产生的种种影响,需要人们在防灾减灾中制定相应措施,达到趋利避害、保障农业的可持续发展。     

沧州金丝小枣主产区气候及农业地质背景分析

通过对沧州主产区金丝小枣生长的气候和土壤适宜条件与沧州当地的气候、土壤及地质地貌特征的对比分析,认为沧州多春旱,夏季温度适宜,光照充足,氮、磷和钾等大量元素和有机质以及微量元素充足,土壤结构适宜,盐碱土壤等条件,不仅适宜小枣生长,还造就了沧州金丝小枣优良的品质。     

山西省朔州市冬季气温变化特征与暖冬的气象成因及对农林业的影响

为了揭示朔州市冬季的气候变化规律,特别是近年冬季的气候变化特点,运用气候倾向率、相关分析等统计方法,根据山西省朔州市6个气象观测站1988-2005年冬季平均气温、平均最高气温、平均最低气温资料,对朔州市近18年来冬季气温变化做了分析。结果表明,自20世纪70年代,朔州市冬季气温总体呈逐年上升趋势,1988年后的18年,朔州市出现15个暖冬年,冬季平均气温变化趋势不太明显,平均最高气温呈下降趋势,平均最低气温呈上升趋势,但与20世纪后30年相比,升温速率明显下降。冬季平均气温、平均最高气温、平均最低气温的最大增温率均出现在1月,1月变暖趋势最为明显。结论认为,这种经常出现的气候异常,有一定的气象成因,对农林业的生产产生了很大的影响,本文对此进行了分析和讨论,并提出了降低暖冬对农林业危害的建议。     

甘肃省气候条件对马铃薯生产安全影响浅析

分析了气候条件对甘肃省马铃薯生产安全的影响,认为河西地区的降水条件对马铃薯产量的影响各生育阶段均为正效应,其他地区的降水条件对马铃薯产量影响最大的时期为块茎增长期,其中块茎快速增长期为正效应,增长后期呈现负效应;马铃薯出苗至分枝前后,各地的热量条件对产量的影响均不敏感,但块茎增长期的高温则对产量的影响较大。     

气候变暖对宁夏引黄灌区玉米生产的影响

1981～2004年在玉米生长发育期4月下旬至9月中旬对宁夏引黄灌区10个测站的气温进行分析。结果表明,宁夏引黄灌区玉米生长期的气候明显变暖。t检验表明,5～9月日平均气温的突变发生在1993年,突变后的气温比突变前升高了0.7℃。在玉米生长发育各阶段,气温都有所升高,但没有超过玉米生长发育的适宜温度范围。气候变暖为高产品种的引进创造了条件,使玉米单产变率减小,保证了玉米的高产稳产。