中国三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量

为给内蒙古高原区、黄土高原区和西北荒漠绿洲区紫花苜蓿测土施肥奠定科学基础,采用零散实验数据整合法以及养分平衡-地力差减法,开展了三大自然区域紫花苜蓿土壤速效钾丰缺指标和推荐施钾量研究。结果表明,内蒙古高原区紫花苜蓿土壤速效钾第1~4级指标依次为≥342mg/kg、89~342mg/kg、24~89mg/kg和<24mg/kg,黄土高原区第1~6级指标依次为≥171mg/kg、96~171mg/kg、54~96mg/kg、30~54mg/kg、17~30mg/kg和<17mg/kg,西北荒漠绿洲区第1~4级指标依次为≥303mg/kg、140~303mg/kg、65~140mg/kg和<65mg/kg;当目标产量9~27t/hm²、钾肥利用率50%时,第1~6级土壤的推荐施钾量分别为0、54~162kg/hm²、108~324kg/hm²、162~486kg/hm²、216~648kg/hm²和270~810kg/hm²。     

稻虱缨小蜂耐热品系的生物和生态学特征

稻虱缨小蜂Anagrus nilaparvatae Pang et Wang是控制稻飞虱种群暴发的主要寄生性天敌之一，高温是制约其种群动态的重要因子。为了解35℃高温驯化获得的稻虱缨小蜂耐热品系（NR品系）的生防潜力，对不同温度下该品系的发育历期、有效积温、寄主卵选择、产卵量以及极端高温胁迫参数进行了测定。结果发现，与未经高温驯化的稻虱缨小蜂品系（HZ品系）相比，20℃时，NR品系雄蜂的发育速率显著高于HZ品系，这一差异主要表现在卵-幼虫中期和蛹期的发育时间明显缩短。NR品系在高温下能维持正常的产卵能力，35℃下NR品系产卵量仍能达到18.80粒/雌。NR品系有更强的耐极端温度的能力，50℃下NR品系雄蜂的热击倒时间为15.19 min，比HZ品系雄蜂长3.03 min。补充不同营养对NR品系的产卵量存在影响，35℃条件下补充10%蔗糖既能延长其寿命，也能提高产卵量。以上研究结果表明高温驯化得到的稻虱缨小蜂品系在35℃高温环境中能维持正常的生长发育和寄生能力，具备适应稻田夏季高温环境的潜力。     

Projections of temperature extremes based on preferred CMIP5 models:a case study in the Kaidu-Kongqi River basin in Northwest China

The extreme temperature has more outstanding impact on ecology and water resources in arid regions than the average temperature. Using the downscaled daily temperature data from 21 Coupled Model Inter-comparison Project(CMIP) models of NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP) and the observation data, this paper analyzed the changes in temporal and spatiotemporal variation of temperature extremes, i.e., the maximum temperature(Tmax) and minimum temperature(Tmin), in the Kaidu-Kongqi River basin in Northwest China over the period 2020–2050 based on the evaluation of preferred Multi-Model Ensemble(MME). Results showed that the Partial Least Square ensemble mean participated by Preferred Models(PM-PLS) was better representing the temporal change and spatial distribution of temperature extremes during 1961–2005 and was chosen to project the future change. In 2020–2050, the increasing rate of Tmax(Tmin) under RCP(Representative Concentration Pathway) 8.5 will be 2.0(1.6) times that under RCP4.5, and that of Tmin will be larger than that of Tmax under each corresponding RCP. Tmin will keep contributing more to global warming than Tmax. The spatial distribution characteristics of Tmax and Tmin under the two RCPs will overall the same; but compared to the baseline period(1986–2005), the increments of Tmax and Tmin in plain area will be larger than those in mountainous area. With the emission concentration increased, however, the response of Tmax in mountainous area will be more sensitive than that in plain area, and that of Tmin will be equivalently sensitive in mountainous area and plain area. The impacts induced by Tmin will be universal and farreaching. Results of spatiotemporal variation of temperature extremes indicate that large increases in the magnitude of warming in the basin may occur in the future. The projections can provide the scientific basis for water and land plan management and disaster prevention and mitigation in the inland river basin.     

不同施肥处理对马铃薯农田土壤理化性状及产量的影响

为了探究不同施肥处理对马铃薯农田土壤理化性状及产量的影响,试验地采用马铃薯连作模式,设置3个施肥处理,即：单施化肥(T)、有机肥配施化肥(YTF 1/2)、全量有机肥(YTF)。结果表明：在不同施肥处理下马铃薯农田土壤的理化性质和马铃薯产量发生了变化,其中变化最为明显的土壤指标有土壤容重、孔隙度、饱和导水率、有效磷。YTF处理较T处理可分别显著(P<0.05)降低土壤容重16.8%,增加土壤孔隙度12.7%,提升饱和导水率25.3%。YTF处理可显著提升土壤有效磷含量43.0%,但各处理间土壤pH、有机碳、全氮、全磷、碱解氮、速效钾之间差异并未达到显著水平。同时,较之T处理,YTF处理亦可显著提升土壤团聚体含量。YTF和YTF 1/2处理可分别较T处理提升马铃薯产量24.6%和12.8%。因此,施用有机肥不仅可以改善土壤结构,改良土壤物理性状,亦能促产增收。     

气候变化情景下流苏香竹潜在分布区预测

流苏香竹（Chimonocalamus fimbriatus）是云南特有珍稀竹种，主要分布于云南西南部。文章以野外调查获取的流苏香竹分布信息为主，运用最大熵模型（MaxEnt）同时结合地理信息系统（ArcGIS），基于19个气候因子，预测其在当前及未来气候变化情景下的潜在分布区。结果表明：当前流苏香竹的高适生区和中适生区主要分布于德宏州、保山市和临沧市等地，除迪庆州、丽江市和昭通市外，云南其他区域均有低适生区零星分布。在未来2050s和2070s的2个时间段，基于2种不同共享社会经济路径（SSP1-2.6和SSP5-8.5），流苏香竹的高适生区面积呈减少的趋势，尤其是SSP5-8.5路径下，高适生区面积仅为当前的12.51%（2050s）和18.63%（2070s）；中、低适生区在SSP1-2.6路径下，显著扩张（2050s）或略微扩张（2070s），在SSP5-8.5路径下，则大幅收缩。流苏香竹野外实际分布区及其潜在分布区均以斑块状为主，可能与云南特殊的地形、地貌有关。影响流苏香竹分布的主导气候因子为最湿月份降水量、最暖月份最高温度、最干季度降水量和平均气温日较差。流苏香竹对气候变化比较敏感，根据其野外分布状况，建议以就地保护为主、迁地保护为辅，在其潜在适生区内适当引种栽培。     

墨脱县农田土壤养分现状与分布特征

本研究利用2017年墨脱县农田测土配方项目土壤调查数据,运用地统计学方法研究了墨脱县耕层土壤有机质(SOM)、碱解氮(AN)、速效磷(AP)和速效钾(AK)养分含量现状及分布特征,以期为墨脱县耕地土壤科学合理施肥提供理论依据。结果表明:当前墨脱全县土壤SOM、AN、AP和AK平均含量为89.18 g/kg、201.25 mg/kg、11.23 mg/kg、313.17 mg/kg;90%的土壤样本有机质含量处于丰富水平;83%的土壤样本碱解氮含量处于丰富、稍丰等级;84%的土壤样本速效磷含量在中等及中等以下肥力水平;46%的土壤样本速效钾含量处于中等及以下水平。从空间分布来看,土壤SOM、AK总体上呈现西高东低,AN含量由北至南呈升高趋势,土壤AP整体上没有明显的空间变化规律。墨脱县耕地土壤养分整体表现为有机质含量丰富,氮素养分较丰富,磷素养分缺乏现象普遍,钾素养分部分区域缺乏。为提升墨脱县耕地土壤肥力水平,各乡镇应该因地制宜进行土壤培肥。     

云南不同气候带农业气候资源变化特征研究

为分析全省平均以及各气候带光能、热量、水分资源的时空变化特征,使用云南115站及6个气候带代表站1961—2018年的气候要素计算各地农业气候资源统计量。结果表明,光能资源变化以减少趋势为主,出现显著突变,各气候带太阳辐射变化可能会引起云南太阳辐射高低值中心发生变化,2009年以来辐射明显增加可能会导致太阳辐射出现新的变化趋势和突变点;热量资源一致显著增加,喜凉及喜温作物的活动积温、积温持续时间及无霜期长度均显著增加,并且呈现初日提前、终日推后的趋势,对作物生长有利;水分资源总体呈现减少趋势,尤其21世纪以来下降趋势明显,亚热带地区暖干化现象突出,干旱风险等级较高。     

遵义烟区不同海拔下植烟土壤细菌群落及影响因素分析

为探究不同海拔下植烟土壤细菌群落结构特征及影响细菌群落结构的主要因素,在贵州省遵义地区选择海拔800（ZL）、1000（ZS）和1200m（ZH）的3块植烟土壤,采用16S rRNA高通量测序法对植烟土壤微生物多样性进行分析。结果表明,ZL和ZH处理植烟土壤细菌α多样性均低于ZS处理;3个海拔下植烟土壤优势门为放线菌门（Actinobacteriota）、变形菌门（Proteobacteria）、绿弯菌门（Chloroflexi）和酸杆菌门（Acidobacteriota）,放线菌门的相对丰度以ZL处理最高,较ZH处理提高了34.22%;变形菌门表现则相反,ZH处理变形菌门丰度较ZL处理显著提高。绿弯菌门与酸杆菌门丰度在3个海拔处理中表现较为一致,均为ZS>ZL>ZH。聚类热图分析结果显示,土壤含水率和pH与Armatimonadota和蓝细菌门（Gyanobacteria）存在显著正相关关系,与变形菌门存在显著负相关关系;变形菌门、厚壁菌门（Firmicutes）和髌骨菌门（Patescibacteria）与土壤微生物量氮存在显著正相关关系,而与速效钾存在极显著负相关关系。     

Effect of farm management on topsoil organic carbon and aggregate stability in water: A case study from Southwest England,UK

There are few reliable data sets to inspire confidence in policymakers that soil organic carbon (SOC) can be measured on farms. We worked with farmers in the Tamar Valley region of southwest England to select sampling sites under similar conditions (soil type, aspect and slope) and management types. Topsoils (2–15 cm) were sampled in autumn 2015, and percentage soil organic matter (%SOM) was determined by loss on ignition and used to calculate %SOC. We also used the stability of macroaggregates in cold water (WSA) (‘soil slaking’) as a measure of ‘soil health’ and investigated its relationship with SOC in the clay‐rich soils. %SOM was significantly different between management types in the order woodland (11.1%) = permanent pasture (9.5%) > ley‐arable rotation (7.7%) = arable (7.3%). This related directly to SOC stocks that were larger in fields under permanent pasture and woodland compared with those under arable or ley‐arable rotation whether corrected for clay content (F = 8.500, p < .0001) or not (F = 8.516, p < .0001). WSA scores were strongly correlated with SOC content whether corrected for clay content (SOC_adj R² = .571, p < .0001) or not (SOC_unadj R² = 0.490, p = .002). Time since tillage controlled SOC stocks and WSA scores, accounting for 75.5% and 51.3% of the total variation, respectively. We conclude that (1) SOC can be reliably measured in farmed soils using accepted protocols and related to land management and (2) WSA scores can be rapidly measured in clay soils and related to SOC stocks and soil management.     

耐低温耐低氧萌发野败不育系赣野A的选育

赣野A是江西省农科院水稻研究所将东乡野生稻的耐冷性和耐低氧萌发能力导入抗稻瘟病保持系赣香B后再与赣香A测交和回交育成的野败型三系籼稻不育系。该不育系败育彻底,异交结实率高,配合力较强,具有较强的耐冷性和耐低氧萌发能力,在直播杂交稻育种中应用前景广阔。2019年通过了江西省品种审定。