A comparison of crop data measured by two commercial sensors for variable-rate nitrogen application

Nitrogen (N) fertilizer rates applied spatially according to crop requirements can improve the efficiency of N use. The study compares the performance of two commercial sensors, the Yara N-Sensor/FieldScan (Yara International ASA, Germany) and the GreenSeeker (NTech Industries Inc., Ukiah, California, USA), for assessing the status of N in spring wheat (Triticum aestivum L.) and corn (Zea mays L.). Four experiments were conducted at different locations in Quebec and Ontario, Canada. The normalized difference vegetation index (NDVI) was determined with the two sensors at specific growth stages. The NDVI values derived from Yara N-Sensor/FieldScan correlated with those from GreenSeeker, but only at the early growth stages, where the NDVI values varied from 0.2 to 0.6. Both sensors were capable of describing the N condition of the crop or variation in the stand, but each sensor had its own sensitivity characteristics. It follows that the algorithms developed with one sensor for variable-rate N application cannot be transferred directly to another sensor. The Yara N-Sensor/FieldScan views the crop at an oblique angle over the rows and detects more biomass per unit of soil surface compared to the GreenSeeker with its nadir (top-down) view of the crop. The Yara N-Sensor/FieldScan should be used before growth stage V5 for corn during the season if NDVI is used to derive crop N requirements. GreenSeeker performed well where NDVI values were >0.5. However, unlike GreenSeeker, the Yara N-Sensor/FieldScan can also record spectral information from wavebands other than red and near infrared, and more vegetation indices can be derived that might relate better to N status than NDVI.     

稻草还田与施氮量对水稻氮素吸收及产量影响

以寒地水稻品种为试验材料,设置稻草不还田、0.5倍、1.0倍、1.5倍、2倍还田5个处理,N0(不施入尿素)、N1(150 kg·hm~(-2))、N2(300 kg·hm~(-2))3个氮肥施用水平,研究不同时期水稻氮素吸收情况、氮素积累量、氮素分配率以及水稻产量。结果表明,分蘖期稻草还田量增加抑制水稻氮素吸收及积累,抑制作用随施氮量增加而降低;幼穗分化期稻草还田促进水稻地下部分氮素吸收,在不同施氮量条件下,0.5倍还田处理氮素积累量达最高值;收获期水稻地上和地下部分氮素均向籽粒部分转移,稻草还田配施氮肥情况下水稻分蘖及有效分蘖提升,N1施肥水平下1.0倍还田处理产量达最高值,N2施肥水平下0.5倍还田处理达最高值,稻草还田不配施氮肥或配施氮肥情况下稻草还田过量均降低水稻产量。     

Effects of nitrogen management on the ratoon crop yield and head rice yield in South USA

Ratoon rice cropping is an important component of the rice cropping system in Texas and south Louisiana, USA, and expanded to Asian countries in 1970. Two field studies were conducted with widely planted rice(Oryza sativa L.) cultivars at Eagle Lake, Texas, USA to determine the effects of nitrogen(N) management in main(first) crop(MC) and ratoon(second) crop(RC) on RC yield. In 2012 and 2013, one cultivar(Presidio) was adopted to determine the effects of RC N management on ratoon yield and head rice yield. In 2016 and 2017, CL153, CL163 and CL272 in addition to Presidio were adopted to examine the effect of MC N management on ratoon yield and head rice yield. N applied at preflood after MC harvest considerably improved RC yield. Application of 99 kg N ha–1 at preflood after MC harvest was practically adequate for RC regrowth, development and approaching the yield potential for Presidio. RC could produce quite high average grain yields of 5.90 to 6.53 t ha–1 in 2012 and 2013, respectively. Main crop N rate only significantly affected MC yield; however, given N applied of 99 kg ha–1 at preflood after MC harvest, ratoon yield was not significantly affected by MC N rate. Neither the main nor ratoon crop N management had a significant effect on RC head rice yield. Considerable RC head rice yields(55–65%) were observed in all of the four cultivars and 4 years except for CL272 in 2016. These results indicat that without very high N fertilizer application, rice ratoon crop could produce a considerable grain yield and an expectative head rice yield. Rice ratooning could be a practical way to increase rice yields with the minimal input in south Texas and regions with a similar climate.     

农艺深施及配施缓控释氮肥对水稻产量及氮素损失的影响

为探讨基肥"干施湿混"（施基肥-泡田-旋耙整田）结合追肥"以水带氮"（先施追肥再灌水）的农艺深施技术及其配施缓控释氮肥对氮素损失及水稻氮素吸收利用的影响,采用田间小区试验,设置不施氮肥（N0）、常规施肥（Nc）、农艺深施（Nd）、农艺深施配施缓控释氮肥再减氮10%（Ns）4个处理,研究了农艺深施及其配施缓控释氮肥对稻田田面水中氮素形态和浓度、稻田氮素流失量、水稻氮素吸收与产量、氮盈余量、土壤有效氮含量的影响。结果表明：与Nc处理相比,Nd和Ns处理均能降低氮素损失高风险期（基肥后7 d内,分蘖肥后5 d内,穗肥后4 d内）稻田田面水中总氮（TN）浓度,降幅分别为18.5%和49.8%,且主要降低了可溶性总氮（DTN）,尤其是铵态氮（NH₄⁺-N）的浓度;Nd和Ns处理稻田TN流失量分别降低了19.1%和47.6%,氮肥表观利用率分别提高了15.3、3.9个百分点,氮素盈余量分别降低了6.8%和38.1%,且土壤有效氮含量和水稻产量均有增加的趋势。研究表明,基肥"干施湿混"结合追肥"以水带氮"的农艺深施技术能降低稻田田面水中氮素浓度,提高氮肥利用率,减少氮肥损失,是一项值得推广的操作简便、绿色增效的施肥技术,再配施缓控释氮肥,能进一步降低田面水中氮素浓度和氮肥损失,同时能减少氮肥用量。     

施氮时期对糜子产量和氮素利用效率的影响

为研究糜子高产栽培的氮肥运筹模式,以晋黍9号为材料,基肥、拔节肥和开花肥以不同比例施用,共设6个处理(N0,N1,N2,N3,N4,N5)。结果表明:分次施肥较一次性施肥有利于糜子产量的增加,以N4(2∶4∶4)的产量最大,为4 575.62kg/hm~2;产量与单株粒重和株高达到极显著正相关,分别为0.93和0.94;氮素养分利用效率、氮肥农学利用率和氮肥偏生产力都以N4处理最大,氮素养分利用效率较N1(基肥100%)和N2(基肥50%、拔节肥50%)分别提高了19.70%和1.31%;氮肥农学利用率较N1和N2分别提高了25.55%和23.64%;氮肥偏生产力较N1和N2分别提高了8.72%和8.07%。所以基肥、拔节期、开花期按2∶4∶4施氮,可以有效地提高糜子产量和氮素利用效率。     

氮量对高产水稻品种产量和氮效率的影响

2018～2019年设置田间小区试验,以主栽高产型水稻品种松粳3号为试验材料,设0、75、105、135、165 kg·hm-2等5个供氮水平,调查水稻分蘖、干物质积累、氮积累、产量和氮效率等指标.施氮促进水稻分蘖发生,施氮和不施氮处理分蘖数差异显著,随施氮量增加,拔节、抽穗、成熟3个时期分蘖数增加量分别为49.54％...     

水稻“定产定氮”节氮施肥技术探讨

我国是世界上氮肥使用量最多的国家,氮素引发的环境问题十分突出。大幅度节氮施肥是解决途径。本文在水稻＂仿森栽培＂实践的基础上,试图将地力差减法定氮引入到移栽水稻大幅度节氮施肥技术中,使之规范化,具体对目标产量、基础产量、单位经济产量吸氮量、氮肥当季利用率等参数的取得及确定进行了探讨。同时也指出了目前常规＂定产定氮＂技术存在的问题;强调科学施肥必须以高利用率为前提。     

追施氮肥对皖麦48产量及主要品质性状的影响

于2005～2006年,选用弱筋小麦新品种皖麦48,通过追氮量和追氮时期两因素试验,研究其对产量和主要品质性状的影响.结果表明:(1)本试验条件下,以追施184.5 kg·hm-2氮素产量最高,在返青期、起身期、拔节期追施,最高产量分别达到6062.5、6 472.0和6 883.0 kg·hm-2.(2)当基肥纯氮迭135 kg·hm-2,籽粒蛋白质含量、湿面筋含量等指标只有在不追肥时才能达到国家弱筋小麦品质标准;而追肥时面团稳定时间、吸水率均达到弱筋小麦品质指标;吹泡仪P和L及P/L值均达到弱筋小麦标准,W值返青期各追肥处理均达到弱筋小麦标准,当起身期追肥低于114 kg·hm-2、拔节期追肥低于90 kg·hm-2时.W值达到弱筋小麦标准.     

追氮量对小黑麦再生草生长和草产量的影响

采用单因素随机区组试验设计,研究追氮量对小黑麦中饲237拔节期刈割后的再生草生长和草产量的影响.结果表明,小黑麦再生草的生长和草产量对追氮量非常敏感,当基施尿素为45 kg·hm-2时,追氮量在0～175 kg·hm-2纯氮范围内,追氮较不追氮能极显著地提高中饲237再生草的茎蘖数、株高和鲜、干草产量(P﹤0.01),再生草株高与追氮量呈线性相关(r＝0.888),茎蘖数、鲜草和干草产量与追氮量呈二次抛物线关系,获得最大鲜、干草产量的追氮临界值为145 kg·hm-2.     

氮肥用量对饲用玉米光合特性以及产量的影响

以中原单32、龙辐208和高油115为材料,研究氮肥用量对饲用玉米光合特性以及产量的影响。结果表明,3个饲用玉米品种叶面积指数、叶绿素a含量、叶绿素b含量和叶绿素总含量在整个生育过程中均呈单峰曲线变化。叶面积指数以N300处理为最高,叶绿素含量以N250处理为最高。饲用玉米生物产量品种间表现为龙辐208>中原单32>高油115,均以N250处理为最高,各处理间生物产量差异均达到极显著水平。饲用玉米光合特性与生物产量呈显著正相关。     

不同施肥量对玉米生育特性及产量的影响

选择最佳施肥量可提高玉米产量、实现经济施肥、降低生产成本。本项试验结果表明,公顷施尿素315 kg、二铵112.5 kg、硫酸钾225 kg、硫酸锌15 kg的施肥量增产效果最佳,可以推广应用。     

减氮对甬优籼粳杂交稻产量和氮肥利用率的影响

于2017—2019年在浙东单季稻区2种类型土壤(象山淡塘泥田和鄞州青紫泥田)上开展定位试验,以4个甬优籼粳杂交稻品种(甬优1540、甬优7850、甬优12、甬优538)和2个常规粳稻品种(宁84和秀水134)为材料,设置HN(农民习惯施氮量,杂交稻折纯N 240 kg·hm-2、常规稻折纯N 200 kg·hm-2)...     

不同施氮量对桂香3号产量及氮肥利用率的影响

[目的]以优质常规稻桂香3号为材料,研究不同施氮水平对其产量和氮素积累与分配特点及氮肥利用率的影响.[方法]田间试验设置5个施氮水平,分别为0、120、150、180和210 kg/ha,测定不同施氮水平下,桂香3号作晚稻种植的产量及其构成、氮素积累与分配比例和氮肥利用率.[结果]桂香3号产量随施氮量的增加而增加,施氮量超过150 kg/ha后产量下降;施氮量主要影响桂香3号的单位面积有效穗数和每穗粒数,对结实率和千粒重影响差异不显著;桂香3号氮素吸收量随施氮量的增加而增加,但氮肥施用过高不利于后期氮素向穗部分配;氮肥偏生产力(NPFP)、氮收获指数(NHI)和氮素籽粒生产效率(NUEg)均随施氮量的升高而下降,但施氮过高或过低均不利于氮肥农学利用率(NAE)、生理利用率(NPE)和吸收利用率(NRE)的增加.[结论]优质常规稻桂香3号适宜施氮量为150kg/ha,其产量最高,达7374.1 kg/ha; NAE、NPE和NRE也均达最大值,分别为15.9 kg/kg、43.8 kg/kg和36.3%.     

生物炭结合氮肥减量对玉米产量和氮效率的影响

为明确施用生物炭条件下氮高效品种玉米的氮效率和适宜减氮量,以氮高效品种郑单958(ZD)和氮低效品种先玉508(XY)为试验材料,以氮肥用量为主区、品种为副区开展裂区试验设计.试验主区共设置5个处理:C0,不施生物炭,施纯N 300 kg·hm-2;C1,施生物炭3000 kg·hm-2和纯N 300 kg·hm-2;...     

施氮量对低谷蛋白水稻产量及品质的影响

【目的】探明施氮量对低谷蛋白水稻Oryza sativa产量及品质的影响。【方法】在大田栽培条件下,设置5个施氮处理,N0、N1、N2、N3和N4处理的施氮量分别为0、90、135、180和225 kg·hm~(-2),研究不同氮肥水平对低谷蛋白水稻‘ER22’产量、籽粒蛋白质组分含量和比例、以及稻米品质的影响。【结果】在施氮量为0～180 kg·hm~(-2)的范围内,有效穗数、结实率、实粒数和水稻产量随着施氮量的增加而逐渐增加;但在N4处理下,结实率与实粒数均下降,导致产量降低。花后7～35 d,‘ER22’籽粒总蛋白含量及各组分蛋白含量均随着施氮量的增加而增加,但各组分蛋白的比例不变;花后35 d籽粒清蛋白和球蛋白含量在N2、N3和N4处理间差异均不显著,而醇溶蛋白含量则在N2、N3和N4处理间差异均显著,谷蛋白含量在N3和N4处理间无显著差异。‘ER22’稻米的食味品质在N1和N2处理下表现良好,N3处理的稻米加工品质最好,N4处理的稻米综合品质降低。【结论】实现低谷蛋白水稻‘ER22’高产优质的适宜施氮范围在135～180 kg·hm~(-2)之间。     

氮肥后移对超级稻扬两优6号产量及氮肥利用率的影响

在基础地力和施氮量相同条件下,研究氮素基蘖肥和穗粒肥不同运筹方式对超级杂交水稻品种扬两优6号产量和氮肥利用率的影响.结果表明,氮肥适当后移可以提高水稻产量和氮肥利用效率,5个处理籽粒产量由高到低顺序是:6 4>5 5>7 3>10 0>CK;氮肥农学利用率为:6 4>5 5>7 3>10 0;氮肥表观利用率为:6 4>7 3>5 5>10 0,说明基蘖肥与穗粒肥比例过高或过低均不利于产量和氮肥利用率提高,分次施用优于一次性施用.由试验可知,6 4处理籽粒产量和氮肥利用率均最高     

河北省猪粪尿氮产生量及氨挥发量的研究

根据统计资料和文献数据,在确定不同养殖方式的(农户散养、集约化养殖)各猪种(育肥猪、母猪、幼猪)氮排泄量和NH3排放因子参数基础上,对2004年河北省农户散养和集约化养殖下各猪种粪尿N产生量及NH3挥发量进行了估算分析。结果表明:(1)2004年河北省猪粪尿N产生量约为81.6×104t,空间变异性较大,主要集中在石家庄、唐山、保定等地区;农户散养下猪粪尿N产生总量约为集约化养殖下总量的2倍;(2)2004年河北省猪粪尿NH3挥发量约为28.5×104t,石家庄、保定、唐山等地区挥发量最大;农户散养下猪粪尿NH3挥发量约为集约化养殖下总量的3倍多;(3)农户散养、集约化养殖下猪粪尿NH3-N损失率分别为34%、19%,集约化养殖要比农户散养更有利于N素保持与利用,有利于减少NH3挥发所带来的环境污染。     

不同种植密度和施氮量对鄂麦195产量的影响

为加速湖北省宜城市小麦品种的更新换代,探索优质中筋专用小麦新品种鄂麦195在宜城市的产量表现,开展了鄂麦195基本苗和施氮量二因素正交栽培试验,以研究鄂麦195最佳的种植密度和施氮量。结果表明,中等肥力条件下,当基本苗为255×10⁴株/hm²、总施氮量为165 kg/hm²时,鄂麦195在宜城市产量最高,为最佳密肥处理。     

Influences of nitrogen fertilizer application rates on radish yield, nutrition quality, and nitrogen recovery efficiency

Radishes (Raphanus sativus L.) were grown in plastic pots in a screenhouse to investigate the influences of nitrogen fertilizer application rates (NFAR) on yield, nitrate content, nitrate reductase activity (NR), nutrition quality, and nitrogen recovery efficiency (NRE) at commercial mature stage. Five N-rate treatments, 0.644, 0.819, 0.995, 1.170, and 1.346 g·pot⁻¹, were set up in the screenhouse pot experiments, and nitrogen fertilizer (unlabeled N and ¹⁵N-labeled fertilizer) was applied as basal dressing and topdressing, respectively. The results indicated that the fresh and dry weight yields of radish increased with the increase of NFAR at the range of 0.099 to 0.180 g N·kg⁻¹ soil, decreased at 0.207 g N·kg⁻¹ soil, and accordingly there was a significant quadratic relationship between the fresh and dry weight yields of radish and the NFAR. At the high addition of urea-N fertilizer, the nitrate content accumulated in the fleshy roots and leaves due to the decline in NR activity. From 0.644 to 0.819 g N·pot⁻¹ NR increased most rapidly, the highest NR activity occurred at 0.819 g N·pot⁻¹, and the lowest NR activity happened at 1.346 g N·pot⁻¹. Soluble sugar and ascorbic acid initially increased to the highest value and then decreased, and, contrarily, crude fiber rapidly decreased with the increase of NFAR. Total N uptake (TNU), N derived from fertilizer (N_dff), and N derived from soil (N_dfs) in radish increased, except that N_dfs relatively and slightly decreased at the rate of 0.207 g N·kg⁻¹soil. The ratio of Ndff to TNU increased, but the ratio of Ndfs to TNU as well as NRE of N fertilizer decreased with the increase of NFAR. Therefore, the appropriate NFAR should be preferably recommended for improving the yields and nutrition qualities of radish and NRE of N fertilizer. These authors contributed equally to this work