黄淮旱地组小麦品种抗旱性鉴定比较分析

为了解近年来黄淮冬麦区旱地组小麦品种抗旱性的整体情况,对2017—2019年黄淮冬麦区132个区试品种（系）在干旱胁迫下的产量及抗旱指数,穗数、穗粒数、千粒重、株高等性状及抗旱系数,进行分析总结。结果表明：黄淮旱肥组、旱薄组、北部组区试品种（系）近年来品种的抗旱性趋势大体相同,胁迫情况下产量总的变化是旱肥组>旱薄组>北部组,且呈逐年稳中有升的趋势,从抗旱指数看,黄淮旱地小麦品种的抗旱整体还处于偏弱的水平;抗旱性状表现为干旱胁迫下均有不同程度的受损,均以千粒重的受损程度最小,有效穗、穗粒数、株高受损程度最大。     

Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.     

土壤湿度对三氮苯类除草剂药效的影响及优化方案

以稗草为生物测定材料,运用二次正交旋转组合设计,以土壤湿度和除草剂用量二因子为决策变量,对稗草的抑制率为目标函数,研究土壤湿度对三氮苯类除草剂药效的影响。结果表明,适当的土壤水分是三氮苯类除草剂发挥药效的重要因素,药效随土壤湿度的提高而提高。不同的土壤湿度对不同除草剂药效影响各异,高湿条件下,湿度差异对药效影响大小依次为嗪草酮、西草净、扑草净、莠去津,低湿条件下则相反。除草剂用量与土壤湿度存在最佳发挥药效的组合。     

Effects of Compound Plant Nutrients on Rumen Fermentation Parameters,Rumen Microbiota and Fatty Acid Composition of Longissimus dorsi Muscle in Finishing Small Tail Han Sheep北大核心CSCD

This study was conducted to investigate the effects of compound p1ant nutrients (CPN) on rumen fermentation parameters, rumen microbiota and fatty acid composition of longissimus dorsi musc1e in finishing sma11 tai1 Han sheep. Sixteen 4-month-o1d finishing sma11 tai1 Han sheep with an initia1 body weight (BW) of (24.18±0.31) kg were random1y divided into two groups, name1y, with 8 rep1icates per group and 1 sheep per rep1icate. The sheep in the contro1 group were fed a basa1 diet, whereas the sheep of the contro1 group (CPN group) was fed the basa1 diet supp1ementation with 3‰ CPN. The experiment 1asted for 97 days after 7 days adaption. The resu1ts showed as fo11ows: compared with the contro1 group, 1) adding CPN decreased the concentration of ammonia nitrogen (NH3-N) (P<0.05); 2) CPN supp1ementation affected beta diversity of rumen microbiota; 3) the re1ative abundance of Acidobacteriota, Erysipe1otrichaceae_UCG-002, Lactobacillus, and Megasphaera were enhanced by adding CPN (P<0.05), whereas, the re1ative abundance of Bacteroidetes and Prevotella was 1ower (P<0.05); 4) the supp1ementation of CPN had no significant effect on fatty acid composition of longissimus dorsi musc1e of fattening sma11-tai1ed Han sheep (P>0.05); 5) the contents of tota1 MUFA, C18:1n9c, C14:1, C16:1, C18:2n6c, C18:3n3 and n-3PUFA in the longissimus dorsi musc1e were corre1ated with the re1ative abundance of Megasphaera, Erysipe1otrichaceae_UCG-002, Succiniclasticum and Ruminococcus (P<0.05). In conc1usion, CPN can regu1ate the rumen microbiota structure and reduce the rumen NH3-N concentration of fattening sma11-tai1ed Han sheep. In production practice, CPN can be used as a rumen eco1ogica1 regu1ator. © 2023 Authors. All rights reserved.     

海产品中副溶血弧菌的分离与鉴定

副溶血弧菌（Vibrio Paraaemolyticus)是一种致病性嗜盐菌，常引起人类食物中毒，通过对四种不同海产品的检测，发现该菌检出率很高，其中，海虾中的检出率高达90％，海产鱼为70％，贝类为60％，海蟹为40％，平均检出率为65％，动物试验证实，该菌致病性较强。     

小陇山林区29年生油松人工林抚育效果评价

运用状态评价和功能评价相结合的方法对油松(Pinus tabulaeformis)人工林中幼林龄抚育间伐前后林分状态变化进行了分析.结果表明:抚育后林木的分布格局由均匀分布靠近随机分布.平均混交度略有上升,幅度不大.但优势树种油松的混交度呈明显上升趋势.油松人工林直径大小比数变化不大,保持了油松在群落中的优势地位.开敞度则由于抚育间伐后林木间距的增大而得以提高,达到了优化目的,林分的胸径平均生长率提高了47.8％,蓄积生长率提高了51.7％,充分说明适宜的抚育间伐可提高林分各树种生长率,从而使林分逐步达到健康稳定的林分结构.抚育间伐样地天然更新增加了11.1％.对照样地天然更新减少了9.8％.     

膜上苗带覆土装置设计与试验研究

在花生机械化播种过程中,膜上苗带覆土的性能直接影响到播种的质量,进而影响到花生的产量.该文基于2BFD-2C型花生覆膜播种机,根据花生种植农艺要求和膜上苗带覆土的技术要求,设计了膜上苗带覆土装置.该装置主要由覆土圆盘、覆土滚筒、漏土缝隙、挡土板和导土板等组成,可一次性完成覆土压膜,横向送土,膜上覆土形成筑土带等作业.该文通过试验确定了各零部件的形式和最优结构参数,进一步提高了播种效率和播种质量,为多功能花生覆膜播种机的膜上苗带覆土装置的设计与应用奠定了一定的理论基础.     

黄旗海水环境质量现状评价

在对黄旗海1999年、2000年和2001年水质监测的基础上,选用LogisticCurve(L-C)水环境质量综合评价模型,以等级评价标准和均匀随机数产生建模样本和验证样本,利用实码加速遗传算法求解评价模型,对黄旗海水环境质量的富营养化进行了现状评价,确定了1999年、2000年和2001年黄旗海的富营养化等级。结果表明:黄旗海1999年、2000年和2001年水质的富营养化程度都处于4级富营养和5级极富营养之间,富营养化等级大小依次为:1999年>2001年>2000年。