巨尾桉苗缺铁黄化病的防治

巨尾桉苗黄化病是一种生理病害,表现为缺素症,主要是缺铁。在缺铁、排水不良、碱性的土壤容易发病,改变土壤理化性的同时施铁元素以及氮、磷、钾等大量元素能使桉苗更好地恢复生长。     

Effects of shading and NO3:NH4 ratio on the yield,quality and N metabolism in strawberry

The effect of 50% shading and NO₃:NH₄ ratio (0:100, 75:25, 50:50, and 25:75) in the nutrient solution on growth, yield, quality and N metabolism in hydroponically grown strawberry (Fragaria × ananassa var Camarosa) was evaluated. Both fresh and dry weights of leaves were significantly lower when a high concentration of either NO₃ (100%) or NH₄ (75%) was the sole N source in the nutrient solution. In unshaded plants, increasing of both NH₄ and NO₃ ratio in the nutrient solution reduced photosynthetic (Pn) rate, however in shaded plants the reduction of Pn became more pronounced at a higher ratio of NH₄ in the nutrient solution. The yield in terms of fresh and dry weight of fruit per plant was significantly increased at the 75:25 and 50:50 (NO₃:NH₄) treatments. Fruit size was significantly affected by the treatments, so that the biggest fruits in both shaded and unshaded plants were obtained under the 75:25 and 50:50 (NO₃:NH₄) treatments. Total soluble solid (TSS) in unshaded plants was increased with increasing NH₄ ratio in the nutrient solution, however in shaded plants it was reduced at high NH₄ ratio in the nutrient solution. In both shaded and unshaded plants, higher concentration of NH₄ significantly reduced the post-harvest life of the fruits. The increase of tissue N concentration was nearly proportional to the NH₄ concentration in the nutrient solution. The activity of nitrate reductase (NR) was increased by increasing NH₄ from 0 to 50% and then reduced at a higher ratio of NH₄ in the solution. Shading increased NH₄ concentration so that the shaded plant had nearly twice as high NH₄ concentration in the leaves. The increase of NH₄ concentration induced by shading could be partially the reduction of NH₄ assimilate because of the shortage of carbohydrate.     

四种阴生地被植物的抗旱性比较研究

通过对4种阴生地被植物（庐山景天Sedum baileyi、翠云草Selaginella uncinata、赤车Pellionia radicans、点腺过路黄Lysimachia hemsleyana）干旱胁迫处理后的生长势、游离脯氨酸含量、水分临界饱和亏、叶保水力和根冠比等指标进行观察测定,发现4种植物中庐山景天和翠云草的抗旱性较强,赤车和点腺过路黄的抗旱性较差。     

一例大食蚁兽贫血的诊治及分析

2017年天津市动物园首次引进大食蚁兽(Myrmecophaga tridactyla),雌、雄各1只,并于2018年7月16日产下1只雌性幼仔。在哺乳期间,雌兽面部出现丘疹状水泡,嗜睡,活动时快速徘徊,显现烦躁状态,四肢明显无力,食欲不佳,易呕吐,反复出血性肠炎。2019年9月,雌兽食量降至健康时的1/3,体重降至35 kg,减少15 kg。血生化检查显示,血氨与治疗后对比异常升高,丙氨酸氨基转移酶升高,红细胞、血红蛋白、血细胞比容偏低。血涂片瑞氏染色可见薄型红血球、卡波德环状小体和偏心红血球。根据实验室检查结果,初步诊断为营养性巨幼细胞贫血合并缺铁性贫血。治疗原则为保肝护肝,补充叶酸、维生素B₁₂和多种矿物质,降低饲料动物性蛋白质含量,调理胃肠道菌群。经过为期1年的治疗调理,该食蚁兽食欲、活动良好,体重增加至45 kg,各项指标趋于正常。     

Root nitrification capacity of lettuce plants with application to aquaponics

Aquaculture and hydroponics have experienced significant growth and market presence in recent years. While aquaponics, the combination of fish and plant culture systems, is beginning to experience the same exponential growth and interest that hydroponics did many years ago, very little information is available on sizing and design of these systems. Incorporation of hydroponic plants with recirculating aquaculture systems (RAS) aids in removal of ammonia/ammonium based wastes, thus reducing the need for water discharge to control water quality. Surface only nitrification rates were quantified to be 0.83g/m²/day for inert surfaces and 0.20/m²/day for root surfaces. Direct assimilation of ammonia by the lettuce plants was less than 2% of the total ammonia and ammonium nitrogen (TAN) removed from the culture water, with the remainder being removal by oxidation of TAN into nitrate.     

雪茄茄衣CX-26品种氮磷钾肥效果及推荐用量研究

为探明雪茄烟适宜氮磷钾施肥量，设计雪茄烟专用肥，采用田间“3414”试验，研究不同氮磷钾肥料处理对雪茄烟产量、分级产量和养分吸收利用的影响。结果表明：（1）与不施肥处理相比，各施肥处理显著提高雪茄烟叶的产量，增产效果：氮肥＞钾肥＞磷肥。（2）氮磷钾肥料的施用均可以优化烟叶等级结构，增加茄衣和茄套的产量，提高产值。（3）N、P2O5、K2O积累量得到增加，氮磷钾最大肥料利用率分别达到38.75%、14.89%和25.20%。（4）一元二次回归拟合发现，烟叶最大产量时的施氮量为138.75 kg/hm2，施磷量为71.85 kg/hm2，施钾量为361.65 kg/hm2。显然，氮磷钾的合理施用可以提高雪茄烟叶的产量，改善雪茄烟叶的质量。     

基于高分卫星遥感的天然草地牧草营养含量季节动态反演的研究

本试验选取了青海省海北地区的海晏县作为研究区域，按照返青期（4-6月）、盛草期（7-9月）、枯黄期（10-12月）和枯草期（1-3月）4个阶段，试图通过实地测量、实验室分析与高分遥感影像相结合，分别筛选与草地各营养指标含量相关性最优的植被指数，建立草地营养含量月际动态估测模型，旨在将高分卫星影像与地面高光谱数据相结合，初步探寻天然草地各营养指标含量的月际动态规律，对指导冷季补饲及实现草地资源最优配置具有重要意义。结果表明：结合高分遥感数据，针对不同月份分别筛选最佳反演模型，对各营养指标含量进行反演，以此分析草场各营养含量月际动态变化规律是可行的；牧草干物质、粗蛋白、钙和磷含量随着返青期-盛草期-枯黄期-枯草期的变化趋势，基本呈现先增后减型变化。4个阶段中，草场干物质和磷含量最大相差约6倍，粗蛋白含量最大相差约7倍，钙含量最大相差约17倍。     

柑桔“石头果”发病原因及防治措施分析

柑桔“石头果”是由于树体缺素引起的一种生理性病害。近年来,在永安市某些柑桔园发生频繁,为害轻的“石头果”减产1%~20%,为害重的减产50%以上,严重影响了柑桔的产量和品质。本文通过对柑桔“石头果”表现症状、发生原因的调查,分析了柑桔“石头果”产生的原因,提出了综合防治措施,以达到丰产、稳产、提质的目的。     

小麦田合理施氮的研究

小麦田对氮肥需求和施肥时间的要求非常严格。在种植中,常见叶片短、窄,茎部叶片先发黄;植株瘦小、直立,分蘖少,穗粒少而小。合理的施氮时间是影响小麦产量的最主要因素。氮肥是小麦生长所必需的大量元素。因此,合理施用氮肥对小麦生长至关重要。     

蓝莓土肥水管理及病虫害防治

蓝莓栽植对土肥水要求严格，适宜土壤pH值在4．5～5．5之间，要施入硫酸铵等肥料，最好进行滴灌供水，并覆盖黑膜，以保证地面潮湿度。蓝莓容易感染枯焦病、急性坏死病、介壳虫、蛆虫、黄刺蛾等病虫害，需注意加强防治。