不同代谢蛋白质水平饲粮对8~10月龄后备奶牛生长发育、血液生化指标和体况评分的影响

本试验旨在研究不同代谢蛋白质(MP)水平饲粮对8~10月龄后备奶牛生长发育、血液生化指标以及体况评分的影响。选取健康的8月龄中国荷斯坦后备奶牛24头,随机分为4组,每组6头,饲喂MP水平分别为9.03%、9.55%、10.09%和10.57%的4种饲粮[对应的小肠可消化粗蛋白质(IDCP)水平分别为6.87%、8.13%、9.40%和10.65%]。预试期15 d,正试期60 d。结果表明:1)MP和IDCP满足线性回归方程MP=6.234+0.408×IDCP(R2=0.999,P0.01,n=4)。2)MP水平为9.03%、9.55%、10.09%和10.57%的4组平均日增重(ADG)分别为0.93、1.04、1.09和1.00 kg/d,10.09%组显著高于9.03%组(P0.05);9.55%组和10.09%组腹围显著或极显著高于9.03%组(P0.05或P0.01)。3)随着MP水平的提高,血清尿素氮(UN)含量逐渐提高,8和9周龄9.55%、10.09%和10.57%组极显著高于9.03%组(P0.01),至10周龄9.55%、10.09%组与9.03%组差异不显著(P0.05)。4)各组试验牛体况评分在3.57~3.90之间,各组之间差异不显著(P0.05),体况发育良好。综合生长发育、血液生化指标和体况评分等各方面的因素,在本试验条件下,饲粮MP水平为10.09%时,可满足8~10月龄中国荷斯坦后备奶牛ADG为1.09 kg/d的生长需要。     

广义严格对角占优矩阵的一个判定方法

文章根据所给的引理给出了一个判定广义严格对角占优矩阵的方法。     

罗布麻叶中蛋白质含量的研究

［目的］研究罗布麻引种驯化成功的生理指标。［方法］采用考马斯亮蓝G 250染色法，对吉林左家地区不同处理方法在不同时间药用植物罗布麻叶中蛋白质含量进行了测定。［结果］在不同处理下罗布麻蛋白质含量不尽相同。根据药用植物的有效成分含量，确定它的最佳采收时间。再根据蛋白质含量在各种罗布麻制品中起的作用，确定罗布麻的最佳种植条件，以提高其利用率。［结论］该研究为罗布麻的进一步开发和利用提供可靠的依据。     

Improvement of High-Temperature Treatment Method using Solar Radiation under Unstable Wind Conditions

Abstract

Open-top chambers (OTC) equipped with solar-heated double funnels (SDF) were tested for high-temperature treatments under unstable wind conditions. OTC-SDFs have two types of funnel-shaped tunnels attached on opposite ends; OTC-SDF-A had SDFs of the same width, and the OTC-SDF-B had SDFs that were twice the width of the open end. The temperature rise in these OTC-SDFs were compared with that in OTC with solar-heated air introduction tunnel (OTC-SAT). The temperature increase in the OTC-SAT during the daytime was small and not flat, whereas that in OTC-SDF-A was higher than in OTC-SAT and almost flat. The temperature rise was further enhanced in the OTC-SDF-B. An increase in air exchange ability at the intake may account for this enhancement. The drop in temperature at night observed in OTC-SAT was less prominent in OTC-SDFs. Based on these data, OTC-SDFs are considered useful in areas where the wind speed and direction are unstable.     

不同柱状田头菇菌株最佳培养条件及亲缘关系的研究

以不同来源的柱状田头菇(Agrocybe aegerita)为研究对象,就不同的碳氮比、pH值以及培养温度对菌丝生长速度和结实性的影响进行了比较研究,并从同工酶角度分析比较了各菌株的亲缘关系。研究结果表明,不同来源的柱状田头菇所要求的最佳培养条件不尽相同。一般情况下,菌丝在碳氮比为10:1～80:1时均可生长,碳氮比为10:1时,菌丝生长最快,且易结实;柱状田头菇可生长并结实的pH值为4～12,最适宜结实的pH值为6;25℃时柱状田头菇菌丝生长速度最快,而20～25℃比较适合其结实。同工酶分析表明,柱状田头菇菌丝中过氧化物同工酶活性不高,酶带单调,不适宜用做检测遗传多样性的生化标记;酯酶同工酶有一定的活性,可以从相似系数上分析不同菌株的亲缘关系。     

巩留野核桃林土壤的形成及其特征特性

本文研究了我国唯一的野核桃自然保护区的野核桃林土壤的形成条件、形成过程、剖面特片及理化特性。野核桃在巩留凯特明山前峡谷的繁衍生息，并发育着野核桃林土壤，是特殊的地质历史条件和小气候等综合作用的结果，野核桃土壤在长期特定的生物、气候条件下，其腐殖化过程和钙积化过程明显，粘化过程较弱。土壤剖面含硅铝高，但分异明显，具有特色。ＡＳ和Ａ１层质地适中，土体温润，结构良好，富含有机质和养分，春肥力较高，林木自     

青海半细毛羊羔羊放牧加补饲育肥试验

在放牧条件下 ,用青海省江河源饲料发展有限公司生产的 3 0 3育肥羊颗粒饲料对 4～ 5月龄青海半细毛羔羊进行放牧加补饲育肥试验 ,每只羊补饲 0 .3 4kg d。育肥期 90d。试验组羊只均活重为 3 4.63± 5 .17kg ,比对照组提高7.90kg ,P <0 .0 1,差异极显著 ,7～ 8月龄羔羊达到出栏标准 ,经济和社会效益显著。     

Nitrogen best management practice for citrus trees: I. Fruit yield,quality, and leaf nutritional status

Elevated levels of nitrate-nitrogen (NO₃-N) in the surficial aquifer above the drinking water quality standard, i.e. maximum contaminant limit (MCL; 10 mg L⁻¹), have been reported in some part of central Florida citrus production regions. Soils in this region are very sandy (sand content >95%), hence are vulnerable to leaching of soluble nutrients and chemicals below the rooting depth of the trees. The objective of this research was to develop N and irrigation best management practices for citrus in sandy soils to maintain optimal crop yield and quality, and to minimize potential leaching of nitrate below the root zone. Six years of field experiment was conducted in a high productive (mean fruit yield > 80 Mg ha⁻¹yr⁻¹) >20-year-old ‘Hamlin’ orange trees [Citrus sinensis (L.) Osbeck] on ‘Cleopatra mandarin’ (Citrus reticulata Blanco) rootstock grown on a well drained Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) in Highland county, FL. Nitrogen rates ranged from 112 to 280 kg ha⁻¹ yr⁻¹ applied as fertigation (FRT), water soluble granular (WSG), 50:50 mix of FRT and WSG, and controlled-release fertilizer (CRF). Tensiometers were used to monitor the soil water content as a basis to schedule optimal irrigation. Fruit yield response over the entire range of N rates was greater for the FRT and WSG sources as compared to that for the WSG + FRT or CRF sources. Using the regression analysis of the fruit yield in relation to N rate, the optimum N rate appeared to be at 260 kg ha⁻¹ yr⁻¹. Based on fruit production response in this study, the N requirement for production of 1 Mg of fruit varied from 2.2 to 2.6 kg across four N sources. This study demonstrated an increased N uptake efficiency, as a result of best management of N and irrigation applications. The optimal N and K concentration in the 4–6-month-old spring flush leaves were 26–30, and 15–18 g kg⁻¹, respectively. However, fruit yield response showed no significant relationship with concentrations of P in the 4–6-month-old spring flush leaves over a range of 0.8–2.4 g kg⁻¹. The results of fate and transport of N in soil and in soil solution with application of different rates and sources of N, and components of citrus tree N budget, are reported in a companion paper.     

金星无核葡萄种胚培养最佳接种期的选择

金星无核葡萄的胚珠可正常受精，绝大多数受精胚在花后21d开始败育。当胚发育最为充分而又尚未败育时取胚珠进行培养，存活胚的比例较高。金星无核葡萄最适宜的接种时期为花后36～39d，此时正是浆果开始软化和着色前期。     

韩城市花椒园土壤养分状况及施肥研究

根据大量土壤样品的分析结果及调查资料，研究了陕西省韩城地区花椒园土壤养分状况、施肥结构和变化趋势。结果表明，供试的180个花椒园施肥量和土壤养分含量变异很大。总体上看，土壤有机质、钾素不足；氮素处于中等水平；磷素较为丰富；微量元素锌、硼、钼极度缺乏；营养元素比例失调，肥料利用率偏低，整体肥力水平低。提出优化施肥结构，增施有机肥、钾肥和微肥，提高花椒产量和品质。