Unmanned aerial vehicle to evaluate frost damage in coffee plants

Damage caused by frost on coffee plants can impact significantly in the reduction of crop quality and productivity. Remote sensing can be used to evaluate the damage caused by frost, providing precise and timely agricultural information to producers, assisting in decision making, and consequently minimizing production losses. In this context, this study aimed to evaluate the potential use of multispectral images obtained by unmanned aerial vehicle (UAV) to analyze and identify damage caused by frost in coffee plants in different climatic favorability zones. Visual evaluations of frost damage and chlorophyll content quantification were carried out in a commercial coffee plantation in Southern Minas Gerais, Brazil. The images were obtained from a multispectral camera coupled to a UAV with rotating wings. The results obtained demonstrated that the vegetation indices had a strong relationship and high accuracy with the frost damage. Among the indices studied the normalized difference vegetation index (NDVI) was the one that had better performances (r?=?? 0.89, R²?=?0.79, MAE?=?10.87 e RMSE?=?14.35). In a simple way, this study demonstrated that multispectral images, obtained from UAV, can provide a fast, continuous, and accessible method to identify and evaluate frost damage in coffee plants. This information is essential for the coffee producer for decision-making and adequate crop management.

     

四株玫烟色拟青霉作为桃蚜微生物防治因子的潜力评价

目的探明球孢白僵菌对不同寄主植物来源蚜虫侵染致病力的差异,为烟蚜高毒力杀虫真菌菌株筛选提供依据。方法以烟草品种K326和红花大金元为烟蚜来源寄主,采用浸渍法进行生物测定,运用“时间—剂量—死亡率”模型分析侵染致病的时间和剂量效应,利用生殖力表法分析接种处理后烟蚜的生殖力特征。结果球孢白僵菌Bb0816菌株对红花大金元和K326烟草品种烟蚜均具有较强的侵染致病力,符合“时间—剂量—死亡率”模型模拟,侵染效应常数分别为0.527和0.532。接种处理后,红花大金元品种烟蚜的死亡率上升最快,在第4~5天达到死亡高峰,而K326烟草品种烟蚜则于第5~6天才达到较高死亡率。从剂量效应来看,该菌株对红花大金元烟草上烟蚜同一时间点的LC₅₀和LC₉₀也小于K326。从时间效应来看,在相同接种剂量下,该菌株对红花大金元烟蚜的LT₅₀和LT₉₀均小于K326;从烟蚜生殖力参数来看,在1.35×10⁵~1.35×10⁸孢子/mL密度下,红花大金元上烟蚜的内禀增长率r_m、净生殖率R₀均低于K326烟蚜,也显著低于对照;在1.35×10³、1.35×10⁴和1.35×10⁵孢子/mL处理下,红花大金元和K326烟草上烟蚜的世代历期间无显著差异,而在高浓度的1.35×10⁷和1.35×10⁸孢子/mL处理下红花大金元烟草上烟蚜世代历期显著小于K326烟蚜。结论烟蚜寄主烟草品种差异影响球孢白僵菌对烟蚜的毒力,在一定剂量范围内,球孢白僵菌对红花大金元烟蚜的侵染致病作用强于K326烟草烟蚜。     

Using an unmanned aerial vehicle to evaluate nitrogen variability and height effect with an active crop canopy sensor

Ground-based active sensors have been used in the past with success in detecting nitrogen (N) variability within maize production systems. The use of unmanned aerial vehicles (UAVs) presents an opportunity to evaluate N variability with unique advantages compared to ground-based systems. The objectives of this study were to: determine if a UAV was a suitable platform for use with an active crop canopy sensor to monitor in-season N status of maize, if UAV’s were a suitable platform, is the UAV and active sensor platform a suitable substitute for current handheld methods, and is there a height effect that may be confounding measurements of N status over crop canopies? In a 2013 study comparing aerial and ground-based sensor platforms, there was no difference in the ability of aerial and ground-based active sensors to detect N rate effects on a maize crop canopy. In a 2014 study, an active sensor mounted on a UAV was able to detect differences in crop canopy N status similarly to a handheld active sensor. The UAV/active sensor system (AerialActive) platform used in this study detected N rate differences in crop canopy N status within a range of 0.5–1.5 m above a relatively uniform turfgrass canopy. The height effect for an active sensor above a crop canopy is sensor- and crop-specific, which needs to be taken into account when implementing such a system. Unmanned aerial vehicles equipped with active crop canopy sensors provide potential for automated data collection to quantify crop stress in addition to passive sensors currently in use.     

飞虱虫疠霉和新蚜虫疠霉对桃蚜的毒力比较

通过飞虱虫疠霉（Ｐａｎｄｏｒａｄｅｌｐｈａｃｉｓ）和新蚜虫疠霉（Ｐ,ｎｅｏａｐｈｉｄｉｓ）对桃蚜（Ｍｙｚｓ　ｐｅｒｓｉｃａｅ）毒 力的生物测定,证实了两种近缘虫疠霉对三日龄若蚜的毒力。两种虫疠霉各包括８个剂量处理,每剂量 接种８８～２１６头若蚜,接种后逐日观察感病死亡数并确诊死因,所获时间－剂量－死亡率数据经模型拟合 分析,结果表明两种虫疠霉具有相似的剂量效应,但飞虱虫疠霉的杀蚜速率比新蚜虫疠霉快。接种后３ ～７ｄ飞虱虫疠霉的ＬＤ５０值分别为１２． ８１,２． ９０,１． ７９,１． ２７,０． ９０个孢子／ｍｍ２,新蚜虫疠霉的ＬＤ５０值分 别为１６． ９６,１． ３０,０． １８,０． ０７,０． ０４个孢子／ｍｍ２．两种虫疠霉的ＬＴ５０值在＞３个孢子／ｍｍ２的剂量下相 似（３．０～３．５ｄ）,但低剂量下差异较大。这些毒力指标表明,飞虱虫疠霉是可以与新蚜虫疠霉匹敌的杀 蚜真菌。     

中国植保无人机发展形势及问题分析

植保无人机作为我国农业航空产业的重要组成之一,近年来的迅猛发展和应用引起了人们广泛的关注。为全面、深入地了解中国植保无人机的发展形势及存在的问题,农业农村部农机化司委托华南农业大学国家精准农业航空施药技术国际联合研究中心统计和撰写了“2016年我国农用植保无人飞机发展形势分析与政策建议”的报告。在此报告的基础上,本文对我国植保无人机的类型、生产企业及保有量分布情况进行了统计和分析,比较全面地展示了中国植保无人机行业的发展状况,总结和提出了目前植保无人机行业发展中在关键施药技术研究、相关标准制订以及监督管理这3个方面存在的主要问题及建议,并对植保无人机的市场前景、关键技术和作业服务模式的发展趋势进行了预测,以期为国内科研机构和企业的科学研究及应用提供参考,加快我国植保无人机产业的发展进程,促进和推动我国植保无人机产业的健康快速发展。     

钾、磷缺乏对番茄植株中碳水化合物分配的影响

低钾处理25d后的番茄植株冠／根比上升；低磷处理的则下降。蔗糖、还原糖和总可溶性糖含量在低钾处理的植株叶片中均上升，根中则下降。低磷处理的植株叶片中，蔗糖、还原糖和总可溶性糖含量基本不变，根中则明显增加。低钾和低磷处理的植株根部可溶性糖占全株总可溶性糖的比例分别为11.3%和46.6%,钾磷供应正常植株分别为31．2％和33．4％。这表明钾和磷在光合产物碳水化合物运输中的作用不同。     

Protein deficiency and tribal warfare in Amazonia: new data

Increasing numbers of anthropological studies about native Amazonian warfare and demographic practices attempt to explain these phenomena as competition over or a response to scarce game animals and other sources of high-quality protein. Recently completed field research among the Yanomam? Indians living at the Venezuela-Brazil border indicates that their protein intake is comparable to that found in highly developed industrialized nations and as much as 200 percent more than many nutritional authorities recommend as daily allowances. Recent data on other Amazonian tribes likewise fails to indicate a correlation between protein intake and intensity of warfare patterns.     

Estimating total leaf nitrogen concentration in winter wheat by canopy hyperspectral data and nitrogen vertical distribution

The use of remote sensing to monitor nitrogen(N) in crops is important for obtaining both economic benefit and ecological value because it helps to improve the efficiency of fertilization and reduces the ecological and environmental burden. In this study, we model the total leaf N concentration(TLNC) in winter wheat constructed from hyperspectral data by considering the vertical N distribution(VND). The field hyperspectral data of winter wheat acquired during the 2013–2014 growing season were used to construct and validate the model. The results show that:(1) the vertical distribution law of LNC was distinct, presenting a quadratic polynomial tendency from the top layer to the bottom layer.(2) The effective layer for remote sensing detection varied at different growth stages. The entire canopy, the three upper layers, the three upper layers, and the top layer are the effective layers at the jointing stage, flag leaf stage, flowering stages, and filling stage, respectively.(3) The TLNC model considering the VND has high predicting accuracy and stability. For models based on the greenness index(GI), mND705(modified normalized difference 705), and normalized difference vegetation index(NDVI), the values for the determining coefficient(R2), and normalized root mean square error(nRMSE) are 0.61 and 8.84%, 0.59 and 8.89%, and 0.53 and 9.37%, respectively. Therefore, the LNC model with VND provides an accurate and non-destructive method to monitor N levels in the field.     

缺钾对生姜吸收铁锰铜锌的影响

试验结果表明:缺钾显著降低生姜吸收铁、铜、锌元素的能力,使生姜各器官的铁、铜、锌含量降低;但缺钾促进了生姜生长前期对锰元素的吸收,提高了锰在地上部的含量,但生长后期生姜体内锰元素流失较早且多,使单株生姜的锰吸收量反而低于正常供钾处理。     

Response of root morphology,physiology and endogenous hormones in maize(Zea mays L.) to potassium deficiency

Potassium(K)deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world.However,the physiological mechanism of K deficiency tolerance is not yet fully understood.To identify the differences of root morphology,physiology and endogenous hormones at different growing stages,two maize inbred lines 90-21-3(tolerance to K deficiency)and D937(sensitive to K deficiency)were cultivated in the long-term K fertilizer experimental pool under high potassium(+K)and low potassium(-K)treatments.The results indicated that the root length,volume and surface area of 90-21-3 were significantly higher than those of D937 under-K treatment at different growing stages.It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under-K treatment.Meanwhile,the values of superoxide dismutase(SOD)and oxidizing force of 90-21-3were apparently higher than those of D937,whereas malondialdehyde(MDA)content of D937 was obviously increased.Compared with+K treatment,the indole-3-acetic acid(IAA)content of 90-21-3 was largely increased under-K treatment,whereas it was sharply decreased in D937.On the contrary,abscisic acid(ABA)content of 90-21-3 was slightly increased,but that of D937 was significantly increased.The zeatin riboside(ZR)content of 90-21-3 was significantly decreased,while that of D937 was relatively increased.These results indicated that the endogenous hormones were stimulated in 90-21-3to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.     

Effects of potassium deficiency on photosynthesis and photoprotection mechanisms in soybean(Glycine max(L.)Merr.)

Potassium is an important nutrient element requiring high concentration for photosynthetic metabolism.The potassium deficiency in soil could inhibit soybean(Glycine max(L.) Merr.) photosynthesis and result in yield reduction.Research on the photosynthetic variations of the different tolerant soyben varieties should provide important information for high yield tolerant soybean breeding program.Two representative soybean varieties Tiefeng 40(tolerance to K~+ deficiency) and GD8521(sensitive to K~+ deficiency) were hydroponically grown to measure the photosynthesis,chlorophyll fluorescence parameters and Rubisco activity under different potassium conditions.With the K-deficiency stress time extending,the net photosynthetic rate(P_n),transpiration rate(T_r) and stomatal conductance(G_s) of GD8521 were significantly decreased under K-deficiency condition,whereas the intercellular CO_2 concentration(C_i) was significantly increased.As a contrast,the variations of Tiefeng 40 were almost little under K-deficiency condition,which indicated tolerance to K~+ deficiency variety could maintain higher efficient photosynthesis.On the 25 th d after treatment,the minimal fluorescence(F_0) of GD8521 was significantly increased and the maximal fluorescence(F_m),the maximum quantum efficiency of PSII photochemistry(F√F_m),actual photochemical efficiency of PSII(φ_(PSII)),photochemical quenching(q_p),and electron transport rate of PSII(ETR)were significantly decreased under K~+ deficiency condition.In addition,the Rubisco content of GD8521 was significantly decreased in leaves.It is particularly noteworthy that the chlorophyll fluorescence parameters and Rubisco content of Tiefeng 40 were unaffected under K~+ deficiency condition.On the other hand,the non-photochemical quenching(q_N) of Tiefeng 40 was significantly increased.The dry matter weight of Tiefeng 40 was little affected under K~+ deficiency condition.Results indicated that Tiefeng 40 could avoid or relieve the destruction of PSII caused by exceeded absorbed solar energy under K-deficiency condition and maintain natural photosynthesis and plant growth.It was an essential physiological mechanism for low-K-tolerant soybean under K-deficiency stress.     

Response of root morphology,physiology and endogenous hormones in maize(Zea mays L.) to potassium deficiency

Potassium(K)deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world.However,the physiological mechanism of K deficiency tolerance is not yet fully understood.To identify the differences of root morphology,physiology and endogenous hormones at different growing stages,two maize inbred lines 90-21-3(tolerance to K deficiency)and D937(sensitive to K deficiency)were cultivated in the long-term K fertilizer experimental pool under high potassium(+K)and low potassium(-K)treatments.The results indicated that the root length,volume and surface area of 90-21-3 were significantly higher than those of D937 under-K treatment at different growing stages.It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under-K treatment.Meanwhile,the values of superoxide dismutase(SOD)and oxidizing force of 90-21-3were apparently higher than those of D937,whereas malondialdehyde(MDA)content of D937 was obviously increased.Compared with+K treatment,the indole-3-acetic acid(IAA)content of 90-21-3 was largely increased under-K treatment,whereas it was sharply decreased in D937.On the contrary,abscisic acid(ABA)content of 90-21-3 was slightly increased,but that of D937 was significantly increased.The zeatin riboside(ZR)content of 90-21-3 was significantly decreased,while that of D937 was relatively increased.These results indicated that the endogenous hormones were stimulated in 90-21-3to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.     

镉胁迫水稻潜热通量与冠层结构参数变化遥感分析镉胁迫水稻潜热通量与冠层结构参数变化遥感分析

为了更准确地监测农田水稻镉污染状况,结合水稻冠层能量平衡和结构参数LAI(Leaf area index),构建水稻生理功能敏感指数Pf(Physiological function sensitivity index),分析水稻镉胁迫水平:首先利用遥感影像数据和实测数据,基于能量平衡模型模拟实验区水稻潜热通量LE(Latent heat flux),然后结合LE与LAI构建水稻生理功能敏感指数Pf,最后根据Pf识别水稻镉胁迫.结果表明,镉胁迫越重水稻LE、LAI和Pf值越小,LE可将水稻镉胁迫区分为重度和轻度/中度两个水平;LAI可将水稻镉胁迫区分为中度/重度和轻度胁迫两个水平;Pf能更好地将水稻镉胁迫区分为轻度、中度和重度三个水平,其区分准确度分别为70.59%、69.05%和84.79%.Pf能有效诊断并定量分析水稻镉污染胁迫状况,为作物重金属污染监测提供重要参考.     

基于无人机可见光影像的树种和树冠信息提取——以晋西黄土区蔡家川流域为例

为探究无人机遥感技术在黄土高原森林资源调查中的适用性,以晋西黄土区蔡家川流域为研究区,以无人机可见光影像为遥感数据源,基于面向对象最邻近分类法,识别并提取研究流域的树种和树冠信息,并与样方调查数据进行对比分析,评估无人机影像提取植被信息的精度及其适用性。结果表明:面向对象最邻近分类法对于郁闭度较低的林分和经济果木林的树种提取效果极好,但复杂植被类型会导致提取精度下降。在农地子流域和人工林子流域上,树种提取的分类混淆矩阵Kappa系数分别为0.898和0.728。面向对象最邻近分类法对人工林和经济果木林的树冠提取精度较高,与实测数据线性回归的决定系数(R²)在0.7以上,但对次生林的树冠提取效果相对较差,R²仅有0.422 3。将该方法拓展应用至流域尺度,识别结果显示,蔡家川流域内人工林子流域主要为刺槐、油松和侧柏混交林,经济作物主要为苹果,油松的林分密度为1 744株·hm^-2,平均冠幅为2.24 m,苹果的林分密度为382株·hm^-2,平均冠幅为4.26 m;农地子流域有苹果树912株,林分密度为439株·hm^-2,平均冠幅为3.84 m。结果表明,基于无人机遥感影像,利用面向对象最邻近分类法可以高效、准确地提取林木株数、郁闭度和平均冠幅,从而有效提高黄土区植被调查的效率。     

Effects of potassium deficiency on photosynthesis,chloroplast ultrastructure,ROS, and antioxidant activities in maize (Zea mays L.)

Potassium(K)deficiency significantly decreases photosynthesis due to leaf chlorosis induced by accumulation of reactive oxygen species(ROS).But,the physiological mechanism for adjusting antioxidative defense system to protect leaf function in maize(Zea mays L.)is unknown.In the present study,four maize inbred lines(K-tolerant,90-21-3 and 099;K-sensitive,D937 and 835)were used to analyze leaf photosynthesis,anatomical structure,chloroplast ultrastructure,ROS,and antioxidant activities.The results showed that the chlorophyll content,net photosynthetic rate(P_n),stomatal conductance(G_s),photochemical quenching(q_P),and electron transport rate of PSII(ETR)in 90-21-3 and 099 were higher than those in D937 and 835 under K deficiency treatment.Parameters of leaf anatomical structure in D937 that were significantly changed under K deficiency treatment include smaller thickness of leaf,lower epidermis cells,and vascular bundle area,whereas the vascular bundle area,xylem vessel number,and area in 90-21-3 were significantly larger or higher.D937 also had seriously damaged chloroplasts and PSII reaction centers along with increased superoxide anion(O_2~-·)and hydrogen peroxide(H_2O_2).Activities of antioxidants,like superoxide dismutase(SOD),catalase(CAT),and ascorbate peroxidase(APX),were significantly stimulated in 90-21-3 resulting in lower levels of O_2~-·and H_2O_2.These results indicated that the K-tolerant maize promoted antioxidant enzyme activities to maintain ROS homeostasis and suffered less oxidative damage on the photosynthetic apparatus,thereby maintaining regular photosynthesis under K deficiency stress.     

无人机飞防技术现状及在我国棉田应用前景分析

目的通过植保无人机在棉花苗期喷雾,探讨纳米农药在棉田的沉积分布及对棉蚜的防治效果。方法采用安阳全丰3WQF120-12型植保无人机在2个飞行高度 (1.5 和2.5 m) 下喷施纳米农药 (3.5%啶虫脒·高效氯氟氰菊酯水性制剂) 和常规农药 (5%啶虫脒+2.5%高效氯氟氰菊酯),以诱惑红为雾滴沉积和农药利用率测定的指示剂,采用Image J软件分析雾滴密度和雾滴覆盖率。结果植保无人机在1.5 和2.5 m飞行高度下喷施常规农药或纳米农药,在棉花上的雾滴沉积密度和覆盖率均无显著差异 (P>0.05),但纳米农药的雾滴密度 (73.84~95.12个/cm²) 和覆盖率 (1.92%~3.22%) 低于常规农药的雾滴密度 (108.57~116.59个/cm²) 和覆盖率 (3.86%~4.08%) ;喷施纳米农药的利用率 (2.39%~2.75%) 低于常规农药 (3.89%~4.09%) ;纳米农药的雾滴粒径更小,施药后7 d的防效 (89.79%~95.23%) 显著高于常规农药的防效 (70.52%~79.01%) (P<0.05),且在1.5 m高度下对棉蚜的防效达到人工喷雾水平。结论在棉花苗期采用植保无人机在1.5 m飞行高度下喷施3.5%啶虫脒·高效氯氟氰菊酯纳米农药可以有效防治棉蚜,可在棉田大面积推广应用。     

The challenge of reproducing remote sensing data from satellites and unmanned aerial vehicles (UAVs) in the context of management zones and precision agriculture

Precision Agriculture - Mapping the within-field variability of crop status is of great importance in precision agriculture, which seeks to balance agronomic inputs with spatial crop demands....     

基于POI数据的合肥中心城区城市公园绿地评估及布局优化

为解决传统公园绿地空间布局评价缺乏人群需求考量和量化支撑的局限性,以合肥中心城区为研究对象,以供需平衡为目标,利用POI数据对公园绿地使用主体分布及活动强度进行量化分析,构建以服务能力与需求评价为核心的公园绿地布局评估模型,并进行实证分析。结果表明:合肥市中心城市公园绿地空间呈“多中心、组团式”的空间不平衡分布特征,公园绿地总体布局和层级设置还不能满足人口的使用需求,不同区域的公园绿地资源配置存在差异化和不平衡现象,针对这些问题提出优化公园绿地布局建议。该模型综合考量了城市公园绿地的供给和需求,量化了供需之间的平衡关系,可以为城市公园绿地布局提供有效的决策支持信息。