Spatial econometric analysis of a field-scale site-specific nitrogen fertilizer experiment on wheat (Triticum aestuvum L.) yield and quality

Knowledge of site-specific response may help farmers to tailor their management decisions with the help of precision farming technologies. However, farmers often have only a vague idea of the economic potential for site-specific management of their fields, which is important for investment decisions on precision farming technologies. This study presents an on-farm experimental approach to identify the economic potential of site-specific fertilization strategies at low costs. A strip trial with winter wheat (Triticum aestivum, L.) was established with precision farming technologies. Twelve different nitrogen fertilizer rates split in two applications were applied to 30 plots over a total strip length of 1.5 km. Geo-referenced yield was recorded with the harvester. Furthermore, electrical conductivity of the soil was measured and grain quality was surveyed with hand selected samples. With the help of advanced spatial statistical methods, within-field site-specific response was modeled with sufficient accuracy at comparably low costs. Electrical conductivity of the soil, elevation above sea level, and derivates of a digital elevation model were used as covariates to identify a possible economic potential for site-specific fertilization. Yield and protein response was best predicted with spatially adjusted regression models with site-characteristics or their interaction with management variables. Protein content was essential for achieving best economic results. The economic potential for site-specific fertilization strategies for the analyzed field was below 2 €/ha. However, the approach to identify the potential may be transferred to other locations with greater potential for site-specific farming.     

Economic feasibility of site-specific optical sensing for managing nitrogen fertilizer for growing wheat

A site-specific nitrogen fertilizer application system that uses optical reflectance measurements of growing wheat plants to estimate N requirements has been developed. The machine enables unique applications of liquid N fertilizer at a grid level of 0.37 m². To achieve widespread adoption, the precision application system must be efficient enough to overcome the cost advantage of pre-plant applications of anhydrous ammonia (NH₃) relative to top-dress applications of either dry or liquid N sources on growing wheat. The objective of this research is to determine if the system is more profitable than conventional methods. Data from on-farm N fertilizer experiments were collected across three years and nine locations in the Southern Plains of the U.S.A. Net returns were calculated for each of eight treatments. The site-specific precision system was competitive economically, but it was not unambiguously superior to the conventional alternatives because it could not overcome the cost advantage of NH₃ pre-plant N sources relative to the cost of applying urea-ammonium nitrate (UAN) during the growing season. The value of the precision system is sensitive to the price of UAN relative to the price of NH₃.

A conceptual framework for judging the precision agriculture hypothesis with regard to site-specific nitrogen application

In this study we derive a test that aims to show that the economic optimum nitrogen applications in site-specific management zones are different. In addition, a confidence interval is derived for the difference between optima, and here we show that separate confidence intervals for either optimum are not as good as the former for judging the precision agriculture hypothesis. Both the test and the confidence interval for the difference are based on modeling the returns above N fertilizer cost by quadratic functions of the nitrogen rate. The data are from an N-rate trial at a heterogeneous field in Thalhausen, Germany. This trial could barely support the economic benefit of precision agriculture. A statistical proof that high- and low-yielding zones should be discriminated against just failed to meet the standard 5% level. We also discuss what design of nitrogen fertilizer levels should be used for the test and the confidence intervals.     

小麦垄作栽培的肥水效应及光能利用分析

小麦垄作栽培中以垄沟内小水渗灌代替传统平作的大水漫灌 ,化肥以垄沟内集中条施代替传统平作的撒施 ,相对增加了施肥深度 ,由此灌溉水的利用率较传统平作提高 1 8 9%～ 3 2 2 % ,氮肥利用率提高1 2 7%～ 1 3 7%。垄作栽培由于改善了田间通风透光条件 ,光能利用率较传统平作提高 1 0 0 %～1 3 2 %。     

氮肥运筹方式对豫单2002产量及品质的影响

【研究目的】该研究旨在为豫单2002的推广应用提供施肥技术支撑,为高产高蛋白夏玉米氮肥合理运筹肥提供理论与技术依据。【方法】在豫北潮土区高产田块上,采用田间试验,设N0(不施氮肥)、N_1(攻杆肥100%)、N_2(攻穗肥100%)、N_3(攻杆肥40% 攻穗肥60%),N_4(攻杆肥30% 攻穗肥50% 攻粒肥20%)五个处理开展研究。【结果】结果表明:氮肥不同运筹方式增产效果差异显著,其中N_3处理增产效果最好,其次是N1处理和N4处理,N_2处理增产效果最小;分次施肥有于提高籽粒粗蛋白含量,且随着施肥次数的增加,籽粒粗蛋白含量呈上升趋势;分次施肥亦有利于提高籽粒蛋白质产量,不同处理以N3最佳,其次为N_4;氮肥不同运筹方式肥料利用率差异显著,其中N_3处理最高,其次为N_4和N_1处理,而N_2最低。【结论】N_3处理由于有效地促进了植株对氮素的吸收利用,增加显著地产量和提高了籽粒蛋白质产量,一定程度上提高了籽粒蛋白质含量,因而为最佳氮肥运筹方式。     

鲁西南地区小麦氮肥后移延衰高产栽培技术探究

氮肥后移延衰高产栽培技术是包括春季追氮时期后移、底追比例后移、适宜的氮素施用量在内的栽培技术体系,适应于水浇条件和肥力条件较好的麦田。     

如皋市小麦精确施氮试验

氮素肥料的用量对弱筋小麦产量和品质的影响至关重要.大面积生产上多数农户凭经验施肥,氮肥施用量偏高,结果往往达不到预期的产量,还造成大量量肥料流失,使肥料利用率隐低,且污染环境.     

氮素形态对小麦花后干物质积累与分配的影响

为探明氮素形态对小麦生育后期干物质生产特性的影响,采用随机区组试验研究了铵态氮、硝态氮和酰胺态氮3种氮素形态处理下小麦花后干物质积累与分配的特性,结果表明:(1)小麦花后籽粒干重及地上部总干重随生育进程不断增加,而旗叶、穗下节、穗下鞘、颖壳的干重均随着生育进程呈下降趋势;(2)氮素形态对小麦花后干物质积累与分配有显著影响.硝态氮处理下小麦花后地上部总干物质量最高,并且随着生育进程,干物质在旗叶、穗下节、穗下鞘、颖壳中分配比例降低,在籽粒中的分配比例高于其他2个处理.(3)铵态氮、硝态氮和酰胺态氮3种氮素形态处理下小麦产量分别为7250.0,7575.3和7156.2 kg/hm2.在此试验条件下,硝态氮处理增产效果最佳,较酰胺态氮处理增产5.8%.     

施氮量与追肥时期对弱筋小麦扬麦9号产量和品质的影响

以扬麦9号为材料,研究施氮量及其追肥时期对弱筋小麦产量和品质的影响。结果表明:增加施氮量可显著提高籽粒产量、蛋白质含量、湿面筋含量、沉降值以及籽粒硬度等主要指标,降低弱筋小麦品质;拔节期以后追施氮肥对产量形成影响最大;追氮时期推迟,可显著提高蛋白质含量、湿面筋含量、沉降值以及硬度等主要品质指标。在该试验条件下,弱筋小麦生产中适宜施氮量为240 kg.hm-2左右,适宜追肥时期为8.1~10.1叶龄期。     

Spectral and thermal sensing for nitrogen and water status in rainfed and irrigated wheat environments

Variable-rate technologies and site-specific crop nutrient management require real-time spatial information about the potential for response to in-season crop management interventions. Thermal and spectral properties of canopies can provide relevant information for non-destructive measurement of crop water and nitrogen stresses. In previous studies, foliage temperature was successfully estimated from canopy-scale (mixed foliage and soil) temperatures and the multispectral Canopy Chlorophyll Content Index (CCCI) was effective in measuring canopy-scale N status in rainfed wheat (Triticum aestivum L.) systems in Horsham, Victoria, Australia. In the present study, results showed that under irrigated wheat systems in Maricopa, Arizona, USA, the theoretical derivation of foliage temperature unmixing produced relationships similar to those in Horsham. Derivation of the CCCI led to an r ² relationship with chlorophyll a of 0.53 after Zadoks stage 43. This was later than the relationship (r ² = 0.68) developed for Horsham after Zadoks stage 33 but early enough to be used for potential mid-season N fertilizer recommendations. Additionally, ground-based hyperspectral data estimated plant N (g kg⁻¹) in Horsham with an r ² = 0.86 but was confounded by water supply and N interactions. By combining canopy thermal and spectral properties, varying water and N status can potentially be identified eventually permitting targeted N applications to those parts of a field where N can be used most efficiently by the crop.     

不同施肥条件下冷、暖型小麦冠层温度的差异

以冷型小麦品种小偃6号、陕229、RB 6和暖型小麦品种NR 9405、9430为供试材料,通过田间小区试验,研究了4种施肥条件(不施肥、单施磷肥、单施氮肥和氮磷配施)下冷、暖型小麦灌浆结实期冠层温度的差异。结果表明,在不施肥、单施磷肥、单施氮肥和氮磷配施条件下,冷型小麦灌浆结实期的冠层温度平均较暖型小麦分别低1.1,1.0,0.9和0.4℃,冷者恒冷、暖者恒暖,冷、暖型小麦冠层温度的差异不因施肥条件的改变而发生根本性的变化;施肥可改变小麦基因型的冠层温度,养分胁迫越严重,冠层温度越高。冷、暖型小麦冠层温度的变化特性为优良小麦品种的选育和进行优质化栽培提供了有利条件。     

全量麦草还田和不同施氮量对水稻的影响

通过研究3种施氮量、2种稻作方式对2个常规粳稻产量及其群体发育特性的影响,结果表明:全量麦草还田处理的产量、成熟期LAI、成穗率、总颖花量、孕穗后群体茎蘖数随施氮量的增加呈先增后减的趋势,以武运粳7号施氮270kg/hm2的产量水平最高,与其他处理间差异均达极显著水平。麦草不还田处理的产量、LAI、成穗率、总颖花量、群体茎蘖数、高峰苗随施氮量的增加而增加,且以300kg/hm2处理的产量水平较高。采用240kg/hm2和270kg/hm2施氮水平时,全量麦草还田处理的产量、成穗率、总颖花量显著高于麦草不还田处理,但施用300kg/hm2处理则相反。因此,可以在生产上推广应用全量麦草还田方法。     

氮肥施用技术对小麦籽粒产量和品质的调控效应

从施氮量、施氮时期、氮肥种类、氯素与其他因素的互作4个方面,综述了国内,陌关氮肥施用技术对小麦籽粒产量和品质影响的研究进展.     

绿肥-水稻轮作体系中氮肥适宜用量研究

连续3年定位试验研究了绿肥-水稻轮作模式下,不同氮肥施用量的土壤肥力、水稻产量和肥料利用率效应。结果表明:绿肥连续还田提高了土壤的基础产量和最高产量,降低了最高产量施肥量。与冬季休闲模式相比,紫云英和蚕豆还田模式的最高产量分别提高10.27%和9.99%,而最高产量施肥量分别降低30.34%和29.65%。综合分析水稻产量、肥料效应、氮素利用率及经济效益等因素,冬季休闲-水稻,冬季紫云英-水稻和冬季蚕豆-水稻3种种植模式的水稻氮肥适宜用量分别为16、12kg/667m2和12kg/667m2。     

油泥土地区小麦磷肥效应试验研究

通过在响水县油泥土地区进行的小麦磷肥效应试验,确定油泥土的土壤磷系数为0.84,有效磷的临界值为17.8 mg/kg。     

秸秆还田配施氮肥对冬小麦产量及氮素调控的影响

以周麦23为供试材料,采用裂区设计的大田试验研究 了关中地区秸秆还田配施不同氮肥水平 对冬小麦产量及氮素调控的影响。结果表明：相较于单施氮肥处理,秸秆还田配施氮肥处理 冬小麦产量在低施氮量处理时有降低的趋势,在高施氮量处理时有增加的趋势,但两者间的 差异不显著;秸秆还田配施氮肥能有效提高冬小麦的氮素利用效率,冬小麦的氮肥表观利用 率提高了1.6%～9.1%;秸秆还田措施配施适量的氮肥有降低冬小麦百公斤籽粒需氮量的趋势 。综合考虑到生产成本及潜在环境污染的可能性因素,在秸秆还田条件下,试验地区冬小 麦施氮量以252～321 kg·hm^-2为宜。     

施氮量对弱筋小麦扬辐麦2号产量和品质调节效应

以弱筋小麦扬辐麦2号为试验材料,研究施氮量对弱筋小麦籽粒产量、蛋白质及其组分含量、淀粉及其组分含量、湿面筋含量的影响。结果表明:在一定施氮量范围内,增施氮肥,籽粒产量、蛋白质和面筋含量提高,淀粉及其组分含量下降;施氮量超过适宜值后,籽粒产量下降,籽粒蛋白质及醇溶蛋白、谷蛋白和面筋含量继续上升,且籽粒蛋白质含量超过弱筋小麦标准;过量施氮,籽粒产量和蛋白质产量均下降,施氮量以172 kg·hm~(-2)左右最为适宜。试验结果初步将弱筋小麦扬辐麦2号的施氮量划分为4个区域,即施氮高效区、产量品质协调施氮区、奢侈施氮区和过量施氮区。     

盐胁迫下施氮水平对小麦籽粒蛋白质和淀粉品质的影响

[目的]为盐碱地优质专用小麦的专业化生产提供理论依据。[方法]以耐盐小麦品种山融3号和盐敏感小麦品种鲁麦15为试材,研究了2种氮肥条件下盐碱地小麦品质性状的变化情况。[结果]在盐碱地条件下,山融3号的籽粒加工品质、面团加工品质和淀粉品质均优于鲁麦15。增施氮肥可提高山融3号的籽粒加工品质,但对鲁麦15籽粒加工品质影响不大。2种类型小麦的面团品质均随施氮量的增加而提高。增施氮肥对鲁麦15籽粒RVA参数的提高幅度大于山融3号。[结论]在盐碱地条件下,增施氮肥可改善耐盐小麦品种的籽粒蛋白质品质和普通小麦的籽粒淀粉品质。     

施氮水平对小麦面条加工品质的影响

 以感官评价为标准，研究施氮水平对不同小麦品种烟农15号和济麦19号中国面条（鲜面条和干面条）加工品质的影响。结果表明，随着施氮水平的提高，小麦面粉蛋白质含量和SDS沉淀值明显增加，并在一定范围内明显改善两品种鲜、干面条的加工品质。施用氮肥对鲜面条品质的影响明显高于对干面条品质的影响，对济麦19号面条品质改善的幅度略大于烟农15号。施用氮肥使烟农15号小麦所制作的鲜面条和干面条的综合评分分别比对照提高10.8%和9.1%，而施用氮肥使济麦19号小麦所制作的鲜面条和干面条的综合评分分别比对照提高12.5%和11.0%。小麦面粉蛋白质含量与面条品质的关系密切。小麦面粉SDS沉淀值与面条品质各参数之间存在正相关关系。施用氮肥改善面条加工品质主要是通过影响面条的韧性、粘性、适口性和表观状态而实现的。