农用车辆自动导航定位方法

农用车辆自动导航技术可有效提高作业精度、实现农田规模化生产。该文以电瓶车为试验平台,使用 RTK DGPS、RTD GPS 和电子罗盘分别采集电瓶车的位置信息和航向角度信息,对农用车辆的导航定位方法进行了研究。试验时,以 RTK DGPS 采集的数据作为标准轨迹。在对试验数据进行空间配准后,采用 Kalman 滤波技术对 RTD GPS 和电子罗盘的数据进行了融合;通过计算综合权重值,对单 GPS 系统和融合系统的性能进行测试与评估,其值分别为 0.006、0.002。由此可知,采用 Kalman 滤波的电子罗盘和 RTD GPS 的组合导航系统,定位精度相对较高,稳定性较好,整体性能优于单 GPS 系统。     

苹果外部缺陷全表面在线检测分选装置研发

中国是水果消费大国,但在水果产后检测装备方面相对滞后。针对目前在线检测装置无法采集苹果全表面图像信息且无法精确计算缺陷面积的问题,该研究以表面缺陷面积的快速检测为主要目标,提出苹果全表面图像合成算法,设计了一套苹果外部品质在线检测及分级装置。该研究以苹果为例,基于球模型提出苹果全表面图像合成算法、缺陷面积校正算法精确计算苹果的表面缺陷面积。通过试验验证,对苹果表面图像进行分割合成后,整体的图像的漏检率为0。提出缺陷面积校正算法,可以计算图像中位于任意位置的苹果缺陷真实面积,选取了120个样本进行验证,其中擦伤样本、碰伤样本、痘斑病样本、表面腐败样本各30个。4种表面损伤面积的预测值和真实值的决定系数R²均在0.97以上,均方根误差(Root Mean Squared Error, RMSE)在4 mm²以下。在偏角试验中,4种表面损伤面积的预测值和真实值的决定系数R²均在0.974 2以上,RMSE在6.304 4 mm²以下。装置检测苹果的速度为2个/s,评级准确率为95%。研究结果表明,检测与苹...     

Comparative Evaluation of Inductively Coupled Plasma–Atomic Emission Spectroscopy and Colorimetric Methods for Determining Hot-Water-Extractable Boron in Soils

Frequency of boron (B) deficiency is increasing in rainfed systems, and hence there is a need to diagnose the deficiency. Colorimetric methods are still widely used in soil-testing laboratories in India for measuring B. Little information is available on the comparative evaluation of the colorimetric and inductively coupled plasma (ICP) methods for determining extractable B in soils. We describe results of the comparative evaluation of these methods for measuring extractable B in 57 soil samples with pH values ranging from 5.3 to 9.5. There was a significant correlation between B values determined by the two methods, and the correlation coefficient was greater for soil samples with pH in the neutral to alkaline range. Interaction between soil samples and methods (ICP or colorimetric) was significant except for soil samples in the pH range of 8.0 to 9.5. Precision for B determination was greater with the ICP than with the colorimetric method.     

Evaluating Nutrient Availability in Semi-arid Soils with Resin Capsules and Conventional Soil Tests,II: Field Studies

Commonly used soil analyses and resin capsules are employed to assess nutrient status in agriculture soils, but their validity in semi-arid ecosystems is unknown. Field studies with six rates of nitrogen (N) and phosphorus (P) application were established on crested wheat stands in both Rush Valley and Skull Valley, Utah. Resin capsule and conventional soil tests for nitrate (NO₃)-N, ammonium (NH₄)-N, and P were administered, and plant nutrient status was examined. Resin capsules were removed and replaced, and soil samples were taken every 90 d for 1 year. Concentration of P in resin capsules was not related to P rate but sodium bicarbonate (NaHCO₃)-extracted P was, and resin NH₄-N, resin NO₃-N, potassium chloride (KCl)–extracted NO₃-N and KCl-extracted NH₄-N were all related to N rate. Only KCl-extracted NO₃-N and NH₄-N levels related to plant tissue N. Overall, traditional soil tests are more effective than resin capsules in semi-arid field conditions, but resin capsules have potential for use in N assessment.     

步进电机变量施肥系统及施肥方案研究

[目的]为了提升我国农业的现代化、电气化、自动化地位,把变量施肥的理念应用到农业生产中,以提高化肥利用率.[方法]以步进电机作为变量施肥系统的执行机构,选用一台两行精密播种施肥机,4种肥料,4组试验.[结果]确定步进电机变量施肥系统最佳方案.[结论]采用获得最佳排肥轮转速和排肥轮长度的方式,可实现按所在地块测土施肥的目的.     

SPR生物传感器连续取样和检测装置研制

为了实现表面等离子共振技术(Surface plasmon resonance,SPR)生物传感器在线检测液态样品,本文研制出一种连续收集液样和检测指标的装置.应用本装置实现了对酸菜液中的大肠杆菌的连续检测,具有精度高、测定时间短等特点,可满足在复杂的现场环境下的检测需要.为以后应用生物传感器进行工厂化在线检测提供依据...     

中国小麦土壤速效钾丰缺指标与适宜施钾量研究

系统总结我国开展的小麦土壤速效钾丰缺指标与适宜施钾量研究,结果表明:30a来我国小麦土壤速效钾丰缺指标明显提高;不同区域之间小麦土壤速效钾丰缺指标差异颇大,以缺钾处理相对产量90%指标为例,土壤NH4OAc-K含量变动于80～246 mg/kg;除黄淮海平原、四川盆地、关中灌区和河套灌区外,我国小麦土壤速效钾丰缺指标研究存在很多空白区域;小麦土壤缺钾较为普遍,第2～4级为土壤速效钾集中分布的丰缺级别,缺钾处理相对产量大多处在70%～100%;土壤养分丰缺指标研究的试验点数不宜过少,丰缺指标高端和低端采用外推数据需谨慎,并应予以注明;适宜施钾量与土壤速效钾丰缺级别线性负相关,与小麦目标产量线性正相关,与钾肥当季利用率线性负相关;当钾肥当季利用率50%、目标产量3.0～12 t/hm2时,土壤速效钾丰缺级别第1～7级的小麦适宜施钾量范围依次为0、17～67、34～134、50～202、67～269、84～336和101～403 kg/hm2。     

农户绿色生产技术采纳行为及其效应——以测土配方施肥技术为例

为揭示农户绿色生产技术采纳行为决策的规律性和显化其行为效应,基于鄱阳湖平原6个产粮大县的607份调查数据,利用内生转换回归（ESR）模型实证分析了农户采纳测土配方施肥技术的影响因素及其采纳行为的经济和生态效应。结果表明：农户采纳测土配方施肥技术主要受到家庭总收入、耕种面积和信息获取渠道的正向影响,耕地破碎度和家离农技机构距离的负向影响。测土配方施肥技术的采纳有助于农户实现水稻的增产和化肥的减量化施用,表现为在反事实假设情景下,实际采纳该技术的农户若未采纳,其水稻单位面积产值下降6.38%、化肥施用量增加2.14%;实际未采纳该技术的农户若采纳,其水稻单位面积产值提高1.83%、化肥施用量减少1.00%。鉴于此,建议降低耕地破碎度,实现适度规模经营,加强技术的宣传推广,构建技术培训体系,显化技术效益,发挥技术的示范带动效果。     

historical review of pig testing programs in Denmark

Until1887pig breeding in Denmark wasbased upon the export to Germany of heavy pigs,weighing from120to150kg.To satisfy thismarket the old native Danish Landrace breed wascrossed with Middle White and Berkshire boarsimported from England in order to produce stillfatter pigs.In1887the importation of Danishpigs became prohibited by Germany and ourfarmers had to change over to the production ofbacon for the English market.This change over was not an easy one.Forthe production of bacon,a comple…     

利用SSR标记进行玉米品种一致性检测研究

为了评估SSR标记在玉米品种一致性鉴定中的应用价值及确定基于SSR标记的玉米一致性鉴定标准,利用13个SSR标记对213份来自2004年国家区域试验的玉米单交种(包括16份重复材料)进行了一致性分析,每个品种取20个个体,除在染色体6和8上各选取了2个和3个标记外,其他染色体上均各选取1个SSR标记.结果显示:一致性检测中异型带的类型有7种,每种出现的概率不同;不同品种在不同引物位点的一致性分布情况差别较大.比较位于同一染色体的引物一致性检测结果,发现在相同染色体上位置较近的不同引物一致性检测结果具有较高的相关性,因此提出在选用一致性检测的引物时应遵循均匀分布的原则,减少引物间的相关性.通过剔除自交个体对品种一致性比率进行校正(仅有7个品种),校正值可反映品种真实的遗传一致性和稳定性.综合考虑品种在单个引物位点的一致性和在所有位点的平均一致性,提出了划分玉米品种一致性级别的标准.