精准农业及其支撑技术

在介绍精准农业(PA)的基本概念的基础上,详细诠释了全球定位系统(GPS)、地理信息系统(GIS)、遥感(RS)、专家系统(ES)、作物管理决策支持系统(DSS)、模型模拟系统(SS)和变量投入技术(VRT)在精准农业中的应用和实施过程.     

赤泥、石灰对Cd污染稻田改制玉米吸收积累Cd的影响

利用Cd污染稻田改制玉米的大田试验,研究了施用赤泥、石灰对玉米吸收积累Cd的影响。结果表明,施用赤泥、石灰对春玉米、秋玉米产量无显著影响,但与施用石灰相比,施用赤泥能显著增加玉米产量和生物量;施用赤泥、石灰皆显著提高了土壤pH值、显著降低了土壤有效态Cd含量,减少了玉米对Cd的吸收积累;春玉米、秋玉米施用赤泥后其籽粒Cd含量分别比对照降低了27.5%和21.1%,施用石灰后则分别降低了26.4%和31.1%;施用赤泥、石灰皆抑制了玉米对Cd的富集和转运,且赤泥抑制玉米茎、叶、籽粒富集Cd的能力优于石灰,但石灰阻控玉米由茎向籽粒及叶片中转运Cd的能力优于赤泥。大田试验结果还表明,稻田改制玉米结合赤泥、石灰等钝化剂的施用可能是一条实现Cd污染农田安全可持续利用的有效途径,也利于保障国家粮食安全和农产品质量安全。     

Long-Term Variable Rate Lime and Phosphorus Application for Piedmont No-Till Field Crops

Variable rate (VR) fertilizer application is a paradigm with potential to improve input efficiency and farm profitability. It is widely marketed by commercial applicators in the southeastern US. However, field studies comparing VR with traditional management have not demonstrated consistent, positive results. The objectives of this study were: (1) to determine the soil impact, crop response and economic potential of VR phosphorus (P) and lime application in a North Carolina Piedmont no-till field crop system using intensive soybean [Glycine max (L.) Merr.] production and (2) to economically evaluate alternatives to standard commercial grid soil sampling for directing VR P and lime. A 23-ha long-term no-till field in the SE Piedmont was divided into 0.4ha plots assigned to either VR or uniform P and lime application. Grid soil sampling and VR P and lime application were done prior to four crops over 3 years: full season soybean, wheat (Triticum aestivum L.)–double cropped soybean, and full season soybean. Soil test P, pH and crop yield response to VR P were inconsistent. Soil pH in areas with low pH initially did increase in response to VR lime, but it took two to three applications to bring all of these areas to the target pH. Once VR-liming raised initially low soil pH to levels close to target, yield of soybean, but not wheat, were up to 0.74Mgha^–1 higher than with uniform lime. Even with significantly higher soybean yields associated with VR lime, 3 years of grid sampling and VR application were not profitable compared to uniform application. The results indicated that VR lime could be profitable if the initial grid sampling data were used either for 2 consecutive years, or if it was used to restrict future grid sampling to specific areas requiring further VR lime.     

Economics of Variable Rate Lime in Indiana

In Indiana, variable rate application (VRA) of lime is often considered a good place to start site-specific management (SSM). This is because soil pH is one of the most variable of manageable soil characteristics in the state, the availability of essential nutrients is closely related to soil pH, and because spreaders can be retrofitted relatively inexpensively to do VRA. The objective of this study is to evaluate the profitability of VRA for lime as a stand-alone activity. The methodology involves a spreadsheet model using corn and soybean pH response functions estimated with small plot data. The overall results indicate increased annual returns to corn and soybean production with site-specific pH management strategies. On average, SSM with agronomic recommendations provides an increased annual return of $7.24 per hectare (ha) (+1.78%). SSM with the economic decision rule provides an average increase in annual return of $19.55 ha^–1 (+4.82%). Information strategy, which uses site-specific information to determine the economically optimal uniform rate of lime, provides an average increase in annual return of $14.38 ha^–1 (+3.54%).     

生物炭对北京郊区砂土持水力和氮淋溶特性影响的土柱模拟研究

为探讨生物炭对北京郊区砂土持水力和氮素淋溶特性的影响,通过分层采集不同深度(0~90 cm)北京郊区沙化地土壤(砂土),模拟田间容重和含水量填装土柱,将生物炭分别按照炭土质量比0%、0.5%、1%、2%和4%施入0~20 cm土层,依据常规施氮肥量(0.56 t N·hm-2)和年平均降雨量(616.6 mm)施肥和滴灌,开展土柱淋溶试验。结果表明:在9次淋溶后,水和总氮的累积淋失量均随着生物炭添加量的增加而减小,与不加炭处理相比最高分别减小41.3%和22.7%。添加生物炭增加了0~20 cm土层总氮含量,最高显著增加158%(P0.05)。淋溶结束后加炭处理土柱土壤中的无机氮总量比不加炭处理高19.5%~91.9%。添加生物炭有利于减小可溶性有机碳的淋失,比不加炭处理最高减小22.8%。淋溶液pH值和电导率随生物炭添加量增加而增大。在9次淋溶过程中,生物炭添加量越大,0~20 cm土层土壤持水量越高。相关性分析表明,总氮淋失量与淋溶液淋失体积显著正相关(r=0.978,P0.01),而与淋溶液中的总氮浓度无正相关关系。生物炭主要通过提高京郊砂土的持水能力,减缓水和氮素向下淋溶的速度,从而减小水和氮素的淋溶损失,提高水肥利用率,降低污染地下水的风险。     

Long-term impact of a precision agriculture system on grain crop production

Research is lacking on the long-term impacts of field-scale precision agriculture practices on grain production. Following more than a decade (1993–2003) of yield and soil mapping and water quality assessment, a multi-faceted, ‘precision agriculture system’ (PAS) was implemented from 2004 to 2014 on a 36-ha field in central Missouri. The PAS targeted management practices that address crop production and environmental issues. It included no-till, cover crops, growing winter wheat (Triticum aestivum L.) instead of corn (Zea mays L.) for field areas where corn was not profitable, site-specific N for wheat and corn using canopy reflectance sensing, variable-rate P, K and lime using intensively grid-sampled data, and targeting of herbicides based on weed pressure. The PAS assessment was accomplished by comparing it to the previous decade of conventional, whole-field corn-soybean (Glycine max L.) mulch-tillage management. In the northern part of the field and compared to pre-PAS corn, relative grain yield of wheat in PAS was greatly improved and temporal yield variation was reduced on shallow topsoil, but relative grain yield was reduced on deep soil in the drainage channel. In the southern part of the field where corn remained in production, PAS did not lead to increased yield, but temporal yield variation was reduced. Across the whole field, soybean yield and temporal yield variation were only marginally influenced by PAS. Spatial yield variation of all three crops was not altered by PAS. Therefore, the greatest production advantage of a decade of precision agriculture was reduced temporal yield variation, which leads to greater yield stability and resilience to changing climate.     

滇西北高原水土保持生态修复措施的土壤理化效应

以滇西北高原香格里拉县纳帕海周边区域的坡耕地、荒草地、自然恢复灌丛、自然恢复高山松次生林以及人工混交林等五种生态系统类型为研究对象,采用时空互代法,将它们当作水土保持生态修复中的不同阶段,研究不同地类土壤理化性质的变化规律。结果表明,从不同土层看,0~20cm土层的土壤孔隙度、自然含水量和pH值比20~50 cm及50~100 cm土层有所增加,土壤容重则比下层减小;土壤有机质、全氮、水解性氮、全磷、速效磷、全钾及速效钾向土壤表层富集。从不同植被类型看,自然恢复灌丛、荒草丛对0~20 cm土层理化性质的改良作用大于人工混交林和高山松次生林。     

土壤质地与烤烟化学成分关系分析

为了探明不同土壤质地对烟叶化学成分的影响,为优质烟叶的生产提供理论依据,以云烟87为试验材料,对紫色土、黄壤土、黄棕壤土和石灰土4中不同类型土壤的理化性质与烤后烟叶化学成分的差异进行相关性分析。结果表明:不同土壤的耕层厚度、速效氮、速效磷及速效钾差异显著,紫色与黄棕壤土两者烤后样的碳和氮化合物及氯含量差异不显著,与石灰土、黄壤土差异显著。典型相关分析表明,烟叶化学成分与黄壤土土壤耕层质地、黄棕壤土的土壤耕层质地和有机质及速效钾、石灰土的土壤有机质及速效氮、紫色土的pH值及速效氮关系密切。     

Profitability of variable rate nitrogen application in wheat production

Using plant sensing to determine the amount of nitrogen (N) to apply has the potential to increase profits in wheat (Triticum aestivum) production by reducing N cost or by increasing grain yield. The objective of this paper was to determine if yields and profits from experimental trials that used a precision N applicator to apply N were significantly different from trials that applied pre-determined amounts of N. Across Oklahoma, USA, experiments were designed to test 10 N treatments that included two variable rate treatments (VRT), two uniform rate treatments (URT) where the level of N applied was based on optical reflectance measurements (ORM), and six conventional treatments (i.e., pre-determined uniform rates of N). Data included treatments during 2005–2009 from eight different locations. Results indicated no statistical difference in yields between the conventional treatments that apply 90 kg ha⁻¹ of N and the VRT and URT treatments. On average, the conventional treatment that applied 90 kg ha⁻¹ of top-dress N produced the largest yield, with a VRT treatment producing the third largest yield. Profits were calculated for each treatment using a partial budget. On average, the treatment that received 90 kg ha⁻¹ of top-dress N was the most profitable even though the pre-plant N (anhydrous ammonia) had a cost advantage relative to top-dress N (urea and ammonium nitrate).     

降水与土壤含水量关系分析

[目的]了解土壤含水量与降水的关系,为防涝抗旱提供依据.[方法]对濉溪县2011-2012年逐日土壤含水量时空变化及其与降水量的关系进行相关分析.[结果]0～60 cm土壤含水量与深度二次曲线相关,低点随含水量增加而下移;20～30、60～100 cm土层含水量与月度二次曲线相关.入渗深度与过程降水量、雨前表土层含水量正相关,入渗速度与雨前表土层含水量负相关,雨后耕层含水量与入渗深度正相关.雨后表土层含水量及变化与雨前表土层含水量和降水量对数正相关,雨后10～20 cm土层含水量及变化与雨前10～20 cm土层含水量和降水量正相关.[结论]濉溪县常年降水量略有不足,要补充灌溉,抓住有利时机实施人工增雨作业.     

盐生植物和秸秆覆盖对滩涂极重度盐土养分和降盐效果的影响

[目的]研究盐生植物和秸秆覆盖对滩涂极重度盐土土壤养分和降盐效果的影响,为沿海滩涂土壤降盐改土提供科学依据.[方法]于2014年5月在江苏沿海滩涂极重度盐土(盐分10g/kg以上)中开展秸秆和植被覆盖的田间试验,设置对照(CK,裸地)、种植碱蓬(PS)、15t/ha秸秆覆盖(SM-A)和30t/ha秸秆覆盖(SM-2A)4种处理,测定各处理0~100cm(即0~10、10~20、20~40、40~60、60~80和80~100cm)土壤各层的盐分含量、pH、水分含量和表层养分含量.[结果]与CK相比,1年后SM-A和SM-2A处理的滩涂极重度盐土0~100cm土壤盐分含量均显著降低(P<0.05,下同),且其0~60、60~80和80~100cm土壤盐分分别降低96.0%、84.9%和55.8%以上;PS处理可显著降低滩涂表层土壤盐分含量,降低土壤盐分51.0%以上,但对20~80cm土壤盐分无明显影响.与CK和PS处理相比,1年后SM-A和SM-2A处理的0~100cm土壤pH和0~60cm土壤水分含量显著提高;与CK相比,桔秆覆盖处理的表层土壤有机碳含量显著降低,但对土壤全氮、碳氮比和容重等无显著影响(P>0.05).[结论]综合考虑降盐和培肥效果,秸秆覆盖处理结合适量有机肥施用可能是将来进行滩涂极重度盐土降盐和培肥改土的重要措施.     

Strategies to evaluate goodness of reference strips for in-season, field scale, irrigated corn nitrogen sufficiency

The nitrogen (N) sufficiency approach to assess plant N status for in-season N management requires a non-N-limiting reference to make N recommendations. Use of reference strips in fields with spatially variable soils and the impact this variability has within N enriched reference strips are not well understood. Consequently three strategies were investigated to evaluate the impact of spatially variable sandy soils within reference strips in two commercial center pivot-irrigated corn fields. Evaluation strategies were: (i) ignore soil spatial variability throughout the reference strips, (ii) account for soil variability in the reference strips based on second-order NRCS soil map units, and (iii) account for soil variability based on apparent electrical conductivity (EC_a) data as a surrogate for soil texture differences in the reference strips. A sufficiency index (SI) calculated from radiometer measured canopy reflectance data (SI_sensor) and from SPAD chlorophyll meter data (SI_meter) at two growth stages during corn vegetative growth were used to assess N sufficiency within the N enriched reference strips. By ignoring soil spatial variability in the reference strips, corn in the sandier soils was designated N deficient. Accounting for soil spatial variability using NRCS soil mapping units improved N sufficiency designations of corn in the reference strip for the different soil types contained within the reference strip but tended to designate corn in lighter texture areas within a mapping unit as N deficient. Use of EC_a as a surrogate for soil texture typically performed best for classifying corn N sufficiency throughout the reference strip and is recommended as a method to obtain reference strip normalizing values in fields with spatially variable sandy soils.     

石灰性紫色水稻土不同土壤深度中厌氧氨氧化细菌对施肥的响应

【目的】研究长期不同施肥处理对水稻土厌氧氨氧化细菌(anaerobic ammonium oxidation bacteria,AAOB)群落结构和垂直分布特征的影响,深入认识不同施肥处理下石灰性紫色水稻土厌氧氨氧化作用的微生物调控机制,为该地区科学施肥、培肥地力提供理论依据。【方法】利用化学分析、末端限制性片段长度多态性分析(T-RFLP)和荧光定量PCR技术分别对不同施肥处理下石灰性紫色水稻土理化性质、厌氧氨氧化细菌丰度及群落结构进行分析。【结果】理化性质结果显示,相对于无肥处理(CK),氮(N)、氮磷钾肥(NPK)及氮磷钾配施农家肥(NPKM)均会降低土壤p H和硝态氮含量,而增加土壤有机质、全氮和铵态氮含量。随土壤深度增加,土壤p H增加,全氮和硝态氮含量降低,铵态氮含量变化趋势不明显。q PCR结果显示,就土壤层次而言,厌氧氨氧化细菌在0—20 cm层的丰度最高,20—40 cm层最低;就施肥处理而言,氮肥(N)对厌氧氨氧化细菌的丰度促进最为明显。T-RFLP结果表明,厌氧氨氧化细菌在0—20 cm土层群落组成最为丰富,Shannon-wiener多样性指数最高;寡氮肥下其群落组成最为简单,无肥处理下群落结构最为复杂。厌氧氨氧化细菌优势种群属于Candidatus Brocadia。冗余梯度分析(RDA)显示,p H影响是石灰性紫色水稻土厌氧氨氧化细菌群落结构差异的主要环境因子。【结论】本研究显示寡氮处理会降低石灰性紫色水稻土中厌氧氨氧化细菌的多样性但促进其丰度。表层土(0—20 cm)是厌氧氨氧化细菌分布的主要层次。     

种稻对周围旱地土壤盐分和土壤水分含量的影响

为了研究种稻对周围旱地影响的程度和范围,选择稻旱田之间无沟和有沟相隔型两种类型,以不受种稻影响的老旱田作对照,在距稻田50、80、150和200m处各埋设定位观测井,监测种稻对地下水埋深、土壤水分含量和土壤盐分含量的影响。结果表明,耕层土壤水分含量与地下水埋深相关极显著,耕层土壤盐分含量与地下水埋深相关极显著,在上升期,旱田距稻田距离与地下水埋深相关极显著。因此,稻旱田之间无沟相隔时,种稻对周围旱地的影响表现为稻田水直接向旱田侧渗,而使距稻田附近旱田的地下水位上升,在距稻田220.7m内地下水位会上升到危害旱作物生长的程度;稻旱田之间有沟相隔时,种稻会导致稻旱田之间排水沟水位上升,从而对周围旱田产生不利影响,这种影响即可通过沟水向旱田的侧渗发生,又表现在阻止旱田的排水上,其不利影响范围在200m以内。     

地表覆盖对旱区土壤水分及菊芋生长的影响

在东北半干旱雨养条件下,以酱菜型菊芋品种榆林6号为供试材料,设置不覆盖(CK)、塑料薄膜覆盖(FM)和玉米秸秆覆盖(CS)3个处理,研究了地表覆盖措施对耕作层土壤水分状况及菊芋生长的影响。结果表明:塑料薄膜覆盖土壤的含水量是不覆盖土壤的1.7~2.0倍,玉米秸秆覆盖土壤的含水量是不覆盖土壤的1.3~2.0倍。与不覆盖处理相比,塑料薄膜覆盖和玉米秸秆覆盖均降低了土壤pH。覆盖措施显著影响了植株生长发育,至开花期玉米秸秆覆盖处理植株最高、茎最粗,株高平均达162cm、茎粗平均达18mm。塑料薄膜覆盖和玉米秸秆覆盖菊芋块茎平均产量为9 585和11 685kg·hm~(-2),分别增产63%和99%。因此,地表覆盖有利于土壤保墒,利于实现干旱地区菊芋的高产、高效栽培,值得推广应用。     

Regional model for nitrogen fertilization of site-specific rainfed corn in haplustolls of the central Pampas,Argentina

In semi-arid regions, soil water and nitrogen (N) are generally limiting factors for corn (Zea mays L.) production; hence, implementation of appropriate N fertilization strategies is needed. The use of precision agriculture practices based on specific site and crop properties may contribute to a better allocation of fertilizer among management zones (MZ). The aim of this study was to develop a model for diagnosis of N availability and recommendation of N fertilizer rates adjusted to MZ for dryland corn crops growing in Haplustolls. The model considered variability between MZ by including site-specific variables [soil available water content at sowing (SAW) and Available Nitrogen (soil available N-NO₃ at planting + applied N, Nd)] using spatial statistical analysis. The study was conducted in Córdoba, Argentina in Haplustolls and consisted in four field trials of N fertilizer (range 0–161 kg N ha⁻¹) in each MZ. The MZ were selected based on elevation maps analysis. Grain yields varied between MZ and increased with larger SAW and Nd at sowing. Grain responses to Nd and SAW in any MZ were not different between sites, allowing to fit a regional model whose parameters (Nd, Nd², SAW, SAW²) contributed significantly (p < 0.001) to yield prediction. Agronomical and economically optimum N rates varied among MZs. However, the spatial variability of optimum N rates among MZs within sites was not enough to recommend variable N fertilizer rates instead of a uniform rate. Variable N fertilizer rates should be recommended only if variability in SAW and soil N among MZ is greater than that found in this work.     

Spatial Variability of Soil Properties, Corn Quality and Yield in Two Illinois, USA Fields: Implications for Precision Corn Management

Better understanding of within-field spatial variability of crop quality parameters and yield are needed for precision management of crops. This study was conducted to determine the magnitude of within-field variability in soil properties, corn (Zea mays L.) quality parameters and yield and to characterize their spatial structures. Another objective was to compare the effects of hybrid on corn quality, yield, and the spatial structure of grain quality. Four Pioneer hybrids were planted side-by-side, two in each of the two study fields in eastern Illinois, USA. Coefficients of variation (CV%) for soil properties varied from 6.3 (pH) to 56.8% (soil test P). All the soil properties (except pH at Site 2) displayed well-defined spatial structures, with either strong or moderate spatial dependence. Variability in corn quality and yield (CVs < 10%) was smaller than variability in soil properties. Most quality parameters examined at Site 1 exhibited either moderate or strong spatial dependence, except that corn oil (both hybrids), kernel roundness and weight (hybrid 33Y18) did not show any spatial correlation. Hybrid 33G26 had significantly higher yield and quality for most quality parameters than 33Y18 at Site 1. At Site 2, hybrid 34W67 was significantly lower in oil and protein content, length, roundness and vitreousness than 34K77, but higher in other quality parameters. Significant differences in spatial structures were also observed across hybrids for some corn quality parameters. We conclude that hybrid selection is an important strategy for precision management of corn for optimum yield and quality.     

生物炭和石灰对红壤理化性质及烟草苗期生长影响的差异

我国南方红壤普遍存在酸性强、铝毒和有效养分含量低等特性,本文研究了生物炭和石灰对红壤理化性质及烟草生长的差异,为烟田红壤改良提供理论基础。采用盆栽试验,设置0、0.5%、1%、2%生物炭用量与传统石灰用量(0.3%)等5个处理,研究了其对红壤pH值、交换性铝和锰、有效态矿质养分含量,以及烟草农艺性状、烟叶矿质养分含量等的影响。结果表明:施用生物炭或石灰后,烟草株高、茎粗和叶片数目等农艺性状明显改善,生物量显著提高。0.5%和1%生物炭处理烟叶的N、P、K、Ca和Mg含量较对照处理明显提高,但2%生物炭处理,烟叶N含量比对照处理降低了9.3%。与对照处理相比,石灰处理中烟叶的N、P和Ca含量增加,K和Mg含量下降。施用生物炭和石灰均能够提高红壤pH值,降低其交换性铝含量;且施用生物炭土壤的碱解氮、速效磷、速效钾、交换性钙和交换性镁含量均高于对照处理;而石灰处理仅交换性钙含量增加,交换性锰含量则减少。因此,施用生物炭和石灰均能促进红壤中烟草的生长,并有效改善红壤的理化性状。     

江西省葛田土壤养分评价及其与块根干重的相关性分析

为摸清江西省粉葛生产状况,为实现葛产业提质增效、绿色发展提供依据,调查分析了江西省15个主产县区具有代表性的17块葛田土壤养分状况,研究了其与单株块根干重的相关性,并分析了限制粉葛产量养分因子.结果表明:(1)调查区土壤pH、有机质、碱解氮、速效磷、速效钾、全氮、全磷和全钾均值分别为4.77 g/kg、20.35 g/...     

佳木斯地区洪河农场土壤线虫优势属的分布

[目的]探究佳木斯地区洪河农场土壤线虫优势属的分布。[方法]研究了佳木斯地区洪河农场土壤线虫优势属在不同土壤深度的垂直分布特征,并分析了不同土地利用方式对线虫优势属分布的影响。[结果]盘旋属(Rotylenchus)集中分布于赤小豆地和玉米地,玉米地中Rotylenchus的数量随土壤深度的增加而增加。大节片线虫属(Macroposthonia)和锉齿属(Mylonchulus)集中分布于林边湿地,其中Mylonchulus的分布表现出表聚性。[结论]土地利用方式对土壤线虫的分布产生影响,不同土壤线虫属的垂直分布存在一定差异。