应用Logistic模型探求封育草场苜蓿种群密度的研究

在陕西渭北对严重退化的半人工草场(天然牧草+紫花苜蓿)进行了为期6年(1986—1991)的封育研究,并应用Logistic模型探讨了该草场主要经济类牧草——紫花苜蓿的最佳种群密度及其封育时限。结果表明,紫花苜蓿种群密度与草场生产力呈显著直线相关,y=1.0819+2.5151x(r=0.9872);其最佳种群密度为76.6——96.0株/m~2;草场封育以3—4年为限:对于轻度过牧的草场,如需封育,用1—2年时间即可重新开放。     

杂交稻新组合钱优817特征特性及高产制种技术探讨

在介绍连晚优质抗病杂交稻新组合钱优817及其亲本特征特性的基础上,总结了钱优817高产制种技术措施,包括适时播种、确定合适的行比和行株距及提高异交结实率等方面。     

贺兰山野化牦牛冬季昼间行为的时间分配

在2009年12月～2010年1月,采用瞬时扫描法和所有事件取样法对贺兰山国家级自然保护区的野化牦牛的冬季行为进行了研究。结果表明,在整个观察期内野化牦牛的各种行为具有较强的规律性,活动时间的分配比例为移动17.31%、站立16.15%、取食34.93%、反刍5.58%、卧息16.53%、其他9.52%。野化牦牛的取食行为在1d内有2个高峰期（9：00～11：00、15：00～17：00）,而野化牦牛的卧息行为的高峰期则出现在13：00～15：00,反刍行为的高峰期在13：00～14：00,牦牛的卧息和反刍行为有部分重叠。牦牛的其他行为在1d中的发生较为随机。年龄因素对野化牦牛冬季昼间的各种行为影响不显著,性别因素对牦牛冬季昼间取食行为和其他行为影响显著,对其余行为影响不显著。     

浸种时间、药剂、秕谷、换水等因素对杂交稻种发芽的影响

本试验模拟农户单季杂交水稻生产的种子浸种催芽过程，研讨了在杭州地区推广种植的3个单季稻主栽品种的浸种催芽过程中时间、药剂、秕谷、换水等因素对种子发芽的影响，提出了单季杂交水稻浸种催芽关键技术。     

不同海拔点食粒豌豆新品种丰产性和稳定性分析

为了科学评价滇中山区新引进的6个秋播食粒豌豆品种的适应性、丰产性和稳定性,采用DPS软件一年多点品种试验的新复极差法、AMMI模型分析和回归系数法,分别对不同海拔试点新品种的综合表现进行分析。结果表明：随着海拔的升高,参试豌豆品种生育期增长,病情指数呈下降趋势,单株生产力逐渐增大。‘云豌18号’具有很高的稳定性,在3个海拔试点有很好的适应性,与对照品种相比平均产量达极显著水平,而‘云豌38号’和‘云豌25号’属于不稳定品种,仅海拔1758 m试点有很好的适应性,综合表现为一般。‘云豌17号’、‘云豌53号’和‘云豌8号’丰产性低、稳定性差,仅海拔1572 m试点有一定适应性,综合表现为较差,没有推广价值。在海拔为1500~1900 m滇中山区秋播食粒豌豆以‘云豌18号’为最佳品种,该品种在此海拔区域内具有很好的稳定性和丰产性,是一个具有推广前景的品种。     

不同割苗期对春玉米产量及植株性状的影响

研究春玉米不同割苗时期对产量性状、根系性状、株高、穗位高的调控效应,明确春玉米在鲁中地区最佳割苗时期。以‘莱农14’和‘登海605’为试验材料,分别在玉米4叶龄、5叶龄、6叶龄、7叶龄期进行割苗处理,以不割苗处理作对照。结果表明,2017年2个品种4叶龄期割苗较对照分别增产12.87%和9.31%,2018年分别增产11.31%和10.15%。5叶龄期割苗增产不显著,6叶龄期割苗‘莱农14’极少数长出再生苗,但很快萎糵,最后死亡;‘登海605’在6叶龄期再生苗无法抽出,7叶龄期2个品种再生苗均无法抽出。2个品种4叶龄期割苗还增加了干物质积累量、根系数量,提高了叶面积指数,降低了株高、穗位高,提高了抗倒伏性能。鲁中地区春玉米产量最高、植株性能最佳的割苗时期为4叶龄期。     

Operational performance in aquaculture: A case study of the manual harvesting of cultivated mussels

Aquaculture is one of the fastest growing food production sectors in recent decades. Such rapid development emphasizes the need to adopt more efficient production strategies while simultaneously increasing productivity and sustainability. Monitoring of production is an important strategy to achieve process efficiency. Therefore, we conducted a time and motion study using operational performance indicators to evaluate mussel harvesting on a commercial marine farm in Southern Brazil. We analyzed the operations of mussel sea withdrawal and disaggregation, which are widely used by local farmers but demanding for workers to perform. Mussel sea withdrawal and disaggregation had standard times of 133.7 and 266.7 s, respectively, for one mussel rope; operational production capacities of 0.16 and 0.08 kg s⁻¹, respectively; operational efficiencies of 100 and 31.6%, respectively; time efficiencies of 56.1 and 34.7%, respectively, rework percentages of 0 and 65%, respectively; and percentages of damaged products of 0 and 3.4%, respectively. These parameters indicate low operational performance. The approach used in this study also allowed us to identify process wastes and propose ways to eliminate or mitigate them, with the aim of adopting more efficient work methods.     

Effects of fruit dipping in hydrochloric acid then rinsing in water on fruit decay and browning of longan fruit

The objective of this study was to find alternative methods for the control of pericarp browning in longan fruits (Dimocarpus longan Lour.) cv. Daw in order to replace the use of sulfur dioxide (SO₂). Experiments were conducted by dipping fruits in 1.5 N HCl solution (pH 0.21) for 20 min followed by draining. The effects of subsequent rinsing in water were also investigated. Untreated fruits and SO₂ fumigated fruits were used as controls. Fruits from each treatment were then packaged in commercial perforated plastic baskets and stored at 3 ± 1 °C, 85% RH for 60 days. It was found that dipping the fruits in HCl controlled disease development compared with the untreated fruits. In addition, dipping the fruits in HCl as well as fumigating with SO₂ gave the best control of pericarp browning. After 5 days, the pericarp of untreated fruits became brown. Dipping fruits in HCl without rinsing reduced pericarp and juice pH and increased titratable acidity which lowered eating quality. Sensory analysis was carried out to determine aril color as well as appearance, firmness, flavor and taste. Dipping in 1.5 N HCl for 20 min and rinsing exhibited higher efficacy than dipping for 0, 10 or 15 min in controlling fruit decay and maintaining fruit color and eating qualities during 7 days storage at 25 °C following 45 days storage at 5 ± 1 °C. Therefore, dipping in 1.5 N HCl for 20 min, followed by rinsing in water can be considered for commercial application in extending shelf life, decreasing fruit decay and maintaining fruit quality of longan fruits.     

密集烘烤关键温度点稳温时间对烟叶颜色和色素降解的影响

为优化密集烘烤工艺，提升烟叶质量特色，对密集烘烤关键温度点不同稳温时间的烟叶颜色参数和质体色素变化进行了研究。结果表明，烘烤过程变黄期关键温度点时间延长，烟叶亮度值、黄度值和叶片饱和度增加；随着定色期关键温度点时间的延长，亮度值降低，但对烟叶黄度值和叶片饱和度影响较小；红度值则随着各关键温度点稳温时间的延长而增加，主脉红度值只有在延长54℃稳温时间时能明显提高；色度角随着稳温时间的延长而降低，烟叶颜色偏向橘黄；在42℃和54℃延长时间有利于降低烟叶正背面色差值；叶绿素和类胡萝卜素随着烘烤时间的延长降解转化更彻底。因此，密集烘烤关键温度点延长稳温时间，在38℃稳温24 h，42℃稳温16 h，47℃稳温20 h，54℃稳温16 h，烟叶内质体色素降解更充分，烤后烟叶颜色和色度增强。