电动多旋翼植保无人机升力特性综合测评方法

升力特性是电动多旋翼植保无人机性能测试的重要参数之一。为了实现对电动多旋翼植保无人机升力特性的性能检测,针对不同型号、不同规格的电动多旋翼植保无人机在评价过程中存在无统一的评价指标问题,该文提出了一种半系留式电动多旋翼植保无人机升力特性的测试与评价方法,包括性能检测平台、升力特性测试方法及指标、升力特性的评价方法。为了验证方法的可行性,对3种不同机型(分别为四旋翼机型Ⅰ、六旋翼机型Ⅱ、八旋翼机型Ⅲ)进行了升力特性指标的性能测试试验。试验结果表明:3种机型在功率载荷、重量效率、热效比等方面有较大差异,功率载荷最好的机型Ⅲ比最差的机型Ⅰ大7.6 m N/W,重量效率最好的机型Ⅰ比最差的机型Ⅱ大0.33,热效比最好的机型Ⅲ比最差的机型Ⅱ大10.5 N/℃,反映出3种机型在设计过程中整个动力系统效率、机型整体结构和材料选择上的差异,从而在整机作业性能上表现出差异。在上述指标测试的基础上,结合无人机动力系统数学模型,提出了运用功率载荷、重量效率和热效比进行电动多旋翼植保无人机升力特性综合评价的评分方法,对上述3种机型进行综合评分的结果为:机型Ⅲ机型Ⅰ机型Ⅱ,该结果表明所提出的评价方法能有效对不同类型电动多旋翼植保无人机的升力特性进行综合评判。该文所给出的测试与评价方法,不仅能用于电动多旋翼植保无人机性能的评测,还能为机型性能的进一步改进提供参考。     

黑龙江泰来在嫩江沙地魔芋引种试验初报

通过在黑龙江泰来县嫩江沙地3年魔芋引种试验,初步表明,魔芋在该地能够生长,宜种植在中性偏酸沙质平缓坡地,每株施1kg马粪,覆地膜,果树玉米套种,无病虫害。     

2种不同类型病毒抑制剂防控TMV的田间药效比较

为评价不同类型病毒抑制剂在不同发病条件下对烟草花叶病的防控效果,选用2种生物制剂(AHO、宁南霉素)和2种化学农药(吗胍·乙酸铜、烯·羟·硫酸铜)进行田间药效试验.大田接种烟草花叶病毒(TMV)的试验表明,AHO和吗胍·乙酸铜对TMV的平均防效较高,分别为41.8％和39.8％,宁南霉素和烯·羟·硫酸铜对TMV的平均防效较低,分别为25.4％和14.5％;在自然发病状态下,AHO对TMV的平均防效为45.5％,宁南霉素的平均防效次之,为36.6％,而烯·羟·硫酸铜和吗胍·乙酸铜的平均防效则分别为28.7％和16.2％.AHO在不同带毒环境下防控烟草花叶病的效果都优于其他3种市售药物,表明其具有开发成为绿色抗烟草花叶病新型农药的潜力.     

辣椒/玉米间作条件下土壤持水能力和作物水分利用特征研究

通过田间小区试验,在辣椒/玉米间作(10:2)条件下,对土壤的持水性能、土壤贮水量和作物水分利用效率特征研究分析。结果表明:(1)生长期间作辣椒第1行和第5行的土壤饱和持水量显著高于单作的玉米和辣椒,生长期的土壤饱和持水量显著高于盛果期;生长期间作辣椒的平均非毛管持水量比单作辣椒高54.86%,呈显著差异。(2)收获期玉米单作地的土壤贮水量显著高于辣椒单作地;收获期土壤平均贮水量相比播种前增加了64.95%。(3)间作辣椒产量和水分利用效率均为中间行显著高于第1行,与单作无显著差异性;间作玉米的产量和水分利用效率显著高于单作。从水分利用角度来看,玉米和辣椒间作能提高土壤持水性能,提高作物产量,也是提高田间有限水分利用效率的可行途径之一。     

Correlation between intercepted radiation and yield of potato crops infested by Phytophthora infestans in central Africa

It became apparent from chemical late blight control data on large numbers of genotypes of the Rwandese late blight screening programme, that yields were linearly related to the amount of intercepted radiation by the crop. Measures which affected the total amount of intercepted radiation such as the use of contact and systematic fungicides, or of different genotypes, did not affect the radiation use efficiency of the canopy. Genotypes that started to tuberize at relatively low values of intercepted radiation partly escaped the effect of late blight infection of the foliage on tuber yields. This characteristic could be useful to identify early late blightresistant genotypes for central Africa, where farmers grow two crops per year and earliness is required.Samenvating De chemische bestrijding van de aardappelziekte in grote aantallen genotypen van het Rwandese veredelingsprogramma voor aardappelziekteresistentie heeft aangetoond dat opbrengsten zich lineair verhouden tot de hoeveelheid door het gewas opgevangen zonnestraling. Maatregelen die van invloed waren op de totale hoeveelheid opgevangen straling, zoals het gebruik van contact- of systemische schimmelbestrijdingsmiddelen, of van verschillende genotypen, waren niet van invloed op het rendement van het gebruik van zonnestraling door het blad. Genotypen die een knolaanleg vertoonden bij verhoudingsgewijze lage waarden van opgevangen straling, ontsnapten gedeeltelijk aan het effect van bladaantasting op knolopbrengst. Dit kenmerk zou van nut kunnen zijn om vroege genotypen te zoeken met resistentie tegen de aardappelziekte in centraal Afrika, waar vroegheid van belang is omdat boeren twee gewassen per jaar telen.     

Yield response of corn to irrigation and nitrogen fertilization in a Mediterranean environment

Productivity and resource-use efficiency in corn (Zea mays L.) are crucial issues in sustainable agriculture, especially in high-demand resource crops such as corn. The aims of this research were to compare irrigation scheduling and nitrogen fertilization rates in corn, evaluating yield, water (WUE), irrigation water (IRRWUE) and nitrogen use (NUE) efficiencies. A 2-year field experiment was carried out in a Mediterranean coastal area of Central Italy (175 mm of rainfall in the corn-growing period) and corn was subjected to three irrigation levels (rainfed and supply at 50 and 100% of crop evapotranspiration, ETc) in interaction with three nitrogen fertilization levels (not fertilized, 15 and 30 g (N) m⁻²). The results indicated a large yearly variability, mainly due to a rainfall event at the silking stage in the first year; a significant irrigation effect was observed for all the variables under study, except for plant population. Nitrogen rates affected grain yield plant⁻¹ and ear⁻¹, grain and biomass yield, HI, WUE, IRRWUE and NUE, with significant differences between non-fertilized and the two fertilized treatments (15 and 30 g (N) m⁻²). Furthermore, deficit irrigation (50% of ETc) was to a large degree equal to 100% of the ETc irrigation regime. A significant interaction “N × I” was observed for grain yield and WUE. The effect of nitrogen availability was amplified at the maximum irrigation water regime. The relationships between grain yield and evapotranspiration showed basal ET, the amount necessary to start producing grain, of about 63 mm in the first and 206 mm in the second year. Rainfed crop depleted most of the water in the 0–0.6 m soil depth range, while irrigated scenarios absorbed soil water within the profile to a depth of 1.0 m. Corn in a Mediterranean area can be cultivated with acceptable yields while saving irrigation water and reducing nitrogen supply and also exploiting the positive interaction between these two factors, so maximizing resource-use efficiency.     

我国主要蔬菜的养分吸收和需求特征

研究我国主要蔬菜养分需求对建立蔬菜推荐施肥新方法至关重要.本文采用文献检索和实地调查采样、测定相结合的方法,依据QUEFTS模型分析了露地白菜、露地萝卜、设施番茄和露地大葱产量与养分吸收之间的关系,获得养分吸收最佳曲线,估算单位蔬菜产量的养分最佳需求量.结果表明,4种蔬菜的产量、养分吸收量和养分内效率(IE)变异很大....     

沙对高尔夫果岭坪床物理特性的影响

对28种沙与泥炭按75∶25混配而成的高尔夫果岭坪床材料的物理特性进行了评价。不同类型沙的粒径、均一性和形状有所不同。高尔夫果岭坪床的物理特性主要取决于所使用的沙的特性。对沙 泥炭混配的坪床来说,其导水率在95~827 mm/h范围内变化,总孔隙度变化范围为38.8%~47.2%,而通气孔隙度(在-3 kPa水势下)为0.9%~24.6%,毛管孔隙度(在-3 kPa水势下)为17.7%~42.1%。结果表明,排水速率和通气孔隙度与毛管孔隙度的平衡主要受沙的粒径大小的影响,起决定作用的是粒径最大和最小的沙所占的比例,而容重、总孔隙度和抗剪切强度取决于沙的均一性。当沙粒较圆且较为光滑时,坪床材料孔隙度趋向减少。沙表面越粗糙,坪床抗剪切能力就越强,而沙对坪床硬度的作用不显著。     

大草蛉对桃蚜和夹竹桃蚜的捕食作用研究

大草蛉在我国分布广泛,能捕食多种农作物害虫。本试验首先研究了大草蛉一龄幼虫对桃蚜、大草蛉二龄幼虫对桃蚜和夹竹桃蚜的捕食功能反应。三个反应的最大捕食量Namax分别为144.93、303.03和151.51(头),瞬时攻击率a分别为0.7428、0.8654和0.6644。大草蛉一龄幼虫有较强的种内干扰反应,随着捕食者密度的增加,捕食作用率(E)依次为0.2025、0.1185、0.0866、0.0694和0.0584;对桃蚜的捕食作用率(E)与自身密度(P)的函数关系式为E=0.2025P-0.7727。在桃蚜和夹竹桃蚜的混合种群中,大草蛉二龄幼虫对桃蚜的选择效应大于夹竹桃蚜。     

水分调控对冬小麦同化物分配与水分利用效率的影响研究

试验研究 12个灌溉组合方式对冬小麦干物质积累与分配、产量和水分利用效率的影响结果表明 ,地面灌水条件下不同处理的地上部干物质积累量由高至低依次为田间持水量 65%的处理 >50 %的处理 >80 %的处理 ;地下 3 0cm、50cm和 10 0cm灌水条件下田间持水量 80 %的处理 >65%的处理 >50 %的处理。产量以地下 3 0cm灌水× 80 %田间持水量处理最高 ,为 6512 .4kg/hm2 ,地下 50cm灌水× 50 %田间持水量处理产量最低 ,为3 568.1kg/hm2 。保持相同田间持水量的灌水处理 ,随灌溉深度的增加其作物水分利用效率呈增大趋势。地下3 0cm灌水× 80 %田间持水量处理和地下 3 0cm灌水× 65%田间持水量处理是较合理的节水灌溉组合方式