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1.
Early in-season loss of N continues to be a problem in corn (Zea mays L.). One method to improve N use efficiency is fertilizing based on in-season crop foliage sensors. The objective of this study was to evaluate two ground-based, active-optical (GBAO) sensors and explore the use of corn height with sensor readings for improving relationships with corn yield. Two GBAO sensors (GreenSeeker® (GS), Trimble, Sunnydale, CA, USA; and Holland Crop Circle (CC) ACS 470 Sensor®, Holland Scientific, Lincoln, NE, USA) were used within 30 established corn N-rate trials in North Dakota at the V6 and V12 growth stages in 2011 and 2012. Corn height was recorded manually at the date of sensor data collection. At the V6 growth stage, the GS relationship to yield and the INSEY (in-season estimate of yield) value was improved when the sensor reading was multiplied times corn height. At the V12 stage, using the GS, the INSEY relationship with yield was also generally increased when height was considered. The CC-based red/near-infrared INSEY relationship with yield was similar to the GS INSEY. The CC-based red edge/near infrared INSEY relationship was increased with height only at the first sensor date, but not with the second. The second CC-based sensor–INSEY relationship with yield was maximized using sensor reading only. Segregating the 30 site data set into sites with high clay surface textures and sites with medium texture improved all INSEY relationships compared to pooling all sites. Relationships between INSEY and corn yield at no-till sites were significant at the V12 stage in the wetter 2011 growing season, but not at the V6 stage either year, nor at the V12 stage in the very dry 2012 season. In the high clay and medium textured soils at the V6 stage, corn height improved the relationship between INSEY and yield often enough to suggest that incorporating corn height into an algorithm for yield prediction would strengthen yield prediction, and thus improve N rate decisions.  相似文献   

2.
Active canopy sensor (ACS)—based precision nitrogen (N) management (PNM) is a promising strategy to improve crop N use efficiency (NUE). The GreenSeeker (GS) sensor with two fixed bands has been applied to improve winter wheat (Triticum aestivum L.) N management in North China Plain (NCP). The Crop Circle (CC) ACS-470 active sensor is user configurable with three wavebands. The objective of this study was to develop a CC ACS-470 sensor-based PNM strategy for winter wheat in NCP and compare it with GS sensor-based N management strategy, soil Nmin test-based in-season N management strategy and conventional farmer’s practice. Four site-years of field N rate experiments were conducted from 2009 to 2013 to identify optimum CC vegetation indices for estimating early season winter wheat plant N uptake (PNU) and grain yield in Quzhou Experiment Station of China Agricultural University located in Hebei province of NCP. Another nine on-farm experiments were conducted at three different villages in Quzhou County in 2012/2013 to evaluate the performance of the developed N management strategy. The results indicated that the CC ACS-470 sensor could significantly improve estimation of early season PNU (R2 = 0.78) and grain yield (R2 = 0.62) of winter wheat over GS sensor (R2 = 0.60 and 0.33, respectively). All three in-season N management strategies achieved similar grain yield as compared with farmer’s practice. The three PNM strategies all significantly reduced N application rates and increased N partial factor productivity (PFP) by an average of 61–67 %. It is concluded that the CC sensor can improve estimation of early season winter wheat PNU and grain yield as compared to the GS sensor, but the PNM strategies based on these two sensors perform equally well for improving winter wheat NUE in NCP. More studies are needed to further develop and evaluate these active sensor-based PNM strategies under more diverse on-farm conditions.  相似文献   

3.
The research reported here seeks to determine whether it is necessary to obtain optical reflectance measurements with a GreenSeeker® handheld sensor from each field to make accurate in-season nitrogen application recommendations for winter wheat, and how much precision—and profit—would be lost by moving from site-specific (or field-specific) optical reflectance sampling to region-level sampling. The approach used was to estimate a separate linear response-plateau regression every year using yield and optical reflectance data from randomized complete block experiments. Profits from region-level sampling and field-level sampling were statistically indistinguishable, but this result was mostly due to both being imprecise. Furthermore, the region- and field-based sampling systems were no better than break-even with the historical extension advice to apply preplant anhydrous ammonia at 90 kg ha?1. The approach of estimating a new regression every year is too imprecise, whether at the field or region level. This research goes beyond past research by accounting for the uncertainty in the estimated relationships. The poor performance of the systems is directly related to the imprecise relationship between yield and optical reflectance responses to nitrogen.  相似文献   

4.
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5.
Optical sensors, coupled with mathematical algorithms, have proven effective at determining more accurate mid-season nitrogen (N) fertilizer recommendations in winter wheat. One parameter required in making these recommendations is in-season grain yield potential at the time of sensing. Four algorithms, with different methods for determining grain yield potential, were evaluated for effectiveness to predict final grain yield and the agronomic optimum N rate (AONR) at 34 site-years. The current N fertilizer optimization algorithm (CNFOA) outperformed the other three algorithms at predicting yield potential with no added N and yield potential with added N (R2 = 0.46 and 0.25, respectively). However, no differences were observed in the amount of variability accounted for among all four algorithms in regards to predicting the AONR. Differences were observed in that the CNFOA and proposed N fertilizer optimization algorithm (PNFOA), under predicted the AONR at approximately 75 % of the site-years; whereas, the generalized algorithm (GA) and modified generalized algorithm (MGA) recommended N rates under the AONR at about 50 % of the site-years. The PNFOA was able to determine N rate recommendations within 20 kg N ha?1 of the AONR for half of the site-years; whereas, the other three algorithms were only able recommend within 20 kg N ha?1 of the AONR for about 40 % of the site-years. Lastly, all four algorithms reported more accurate N rate recommendations compared to non-sensor based methodologies and can more precisely account for the year to year variability in grain yields due to environment.  相似文献   

6.
When utilizing optical sensors to make in-season agronomic recommendations in winter wheat, one parameter often required is the in-season grain yield potential at the time of sensing. Current estimates use an estimate of biomass, such as normalized difference vegetation index (NDVI), and growing degree days (GDDs) from planting to NDVI data collection. The objective of this study was to incorporate soil moisture data to improve the ability to predict final grain yield in-season. Crop NDVI, GDDs that were adjusted based upon if there was adequate water for crop growth, and the amount of soil profile (0–0.80 m) water were incorporated into a multiple linear regression model to predict final grain yield. Twenty-two site-years of N fertility trials with in-season grain yield predictions for growth stages ranging from Feekes 3 to 10 were utilized to calibrate the model. Three models were developed: one for all soil types, one for loamy soil textured sites, and one for coarse soil textured sites. The models were validated with 11 independent site-years of NDVI and weather data. The results indicated there was no added benefit to having separate models based upon soil types. Typically, the models that included soil moisture, more accurately predicted final grain yield. Across all site years and growth stages, yield prediction estimates that included soil moisture had an R2 = 0.49, while the current model without a soil moisture adjustment had an R2 = 0.40.  相似文献   

7.
Nitrogen (N) fertilizer application can lead to increased crop yields but its use efficiency remains generally low which can cause environmental problems related to nitrate leaching as well as nitrous oxide emissions to the atmosphere. The objectives of this study were to: (i) to demonstrate that properly identified variable rates of N fertilizer lead to higher use efficiency and (ii) to evaluate the capability of high spectral resolution satellite to detect within-field crop N response using vegetation indices. This study evaluated three N fertilizer rates (30, 70, and 90 kg N ha?1) and their response on durum wheat yield across the field. Fertilizer rates were identified through the adoption of the SALUS crop model, in addition to a spatial and temporal analysis of observed wheat grain yield maps. Hand-held and high spectral resolution satellite remote sensing data were collected before and after a spring side dress fertilizer application with FieldSpec, HandHeld Pro® and RapidEye?, respectively. Twenty-four vegetation indices were compared to evaluate yield performance. Stable zones within the field were defined by analyzing the spatial stability of crop yield of the previous 5 years (Basso et al. in Eur J Agron 51: 5, 2013). The canopy chlorophyll content index (CCCI) discriminated crop N response with an overall accuracy of 71 %, which allowed assessment of the efficiency of the second N application in a spatial context across each management zone. The CCCI derived from remotely sensed images acquired before and after N fertilization proved useful in understanding the spatial response of crops to N fertilization. Spectral data collected with a handheld radiometer on 100 grid points were used to validate spectral data from remote sensing images in the same locations and to verify the efficacy of the correction algorithms of the raw data. This procedure was presented to demonstrate the accuracy of the satellite data when compared to the handheld data. Variable rate N increased nitrogen use efficiency with differences that can have significant implication to the N2O emissions, nitrate leaching, and farmer’s profit.  相似文献   

8.
Variable-rate application (VRA) addresses in-field variation in soil nitrogen (N) availability and crop response, and as such is a tool for more effective site-specific management. This study assessed the performance of a VRA system for on-the-go delivery of granular fertilizer in 7-m wide and 200-m long strips of a 2.4-ha wheat field. A randomized complete block design consisted of three treatment strips (a preplant uniform application of 100 kg N/ha, a preplant + in-season uniform farmer rate of 212 kg N/ha and a preplant + in-season VRA) within four blocks. The VRA prototype consisted of Crop Circle ACS-430 active canopy sensors, a GeoScout X data logger that processed the geospatial data to convey a real-time N rate signal (1 Hz) to a Gandy Orbit Air 66FSC spreader through a Raven SCS 660 controller. Crop monitoring included analysis of in-season soil and plant samples, water balance and grain yield. VRA delivered an economic optimum N rate using 72% less in-season N or 38% less total N (131 kg N/ha) than that applied by the farmer (212 kg N/ha). The reduction of total N inputs came about without any yield losses and translated to 58% N-use efficiency in comparison to 44% of the farmer practice and 52% of the preplant control. VRA also provided a much higher revenue over fertilizer costs, €68/ha and €118/ha higher than the preplant control and the farmer practice, respectively. The return of VRA per unit of N was equal to that of the large preplant application due to low leaching losses. Overall, the high-resolution VRA was superior in terms of environmental benefits and profitability with the least uncertainty to the farmer.  相似文献   

9.
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10.
A fuzzy inference system (FIS) was developed to generate recommendations for spatially variable applications of N fertilizer. Key soil and plant properties were identified based on experiments with rates ranging from 0 to 250 kg N ha−1 conducted over three seasons (2005, 2006 and 2007) on fields with contrasting apparent soil electrical conductivity (ECa), elevation (ELE) and slope (SLP) features. Mid-season growth was assessed from remotely sensed imagery at 1-m2 resolution. Optimization of N rate by the FIS was defined against maximum corn growth in the weeks following in-season N application. The best mid-season growth was in areas of low ECa, high ELE and low SLP. Under favourable soil conditions, maximum mid-season growth was obtained with low in-season N. Responses to N fertilizer application were better where soil conditions were naturally unfavourable to growth. The N sufficiency index (NSI) was used to judge plant N status just prior to in-season N application. Expert knowledge was formalized as a set of rules involving ECa, ELE, SLP and NSI levels to deliver economically optimal N rates (EONRs). The resulting FIS was tested on an independent set of data (2008). A simulation revealed that using the FIS would have led to an average N saving of 41 kg N ha−1 compared to the recommended uniform rate of 170 kg N ha−1, without a loss of yield. The FIS therefore appears to be useful for incorporating expert knowledge into spatially variable N recommendations.  相似文献   

11.
Effective variable-rate nitrogen (N) management requires an understanding of temporal variability and field-scale spatial interactions (e.g. lateral redistribution of nutrients). Modeling studies, in conjunction with field data, can improve process understanding of agricultural management. CropSyst-Microbasin (CS-MB) is a fully distributed, 3-dimensional hydrologic cropping systems model that simulates small (10 s of hectares) heterogeneous agricultural watersheds with complex terrain. This study used a highly instrumented 10.9 ha watershed in the Inland Pacific Northwest, USA, to: (1) assess the accuracy of CS-MB simulations of field-scale variability in water transport and crop yield in comparison to observed field data, and (2) quantify differences in simulated yield and farm profitability between variable-rate and uniform fertilizer applications in low, average and high precipitation treatments. During water years 2012 and 2013 (a “water year” refers to October 1st through the following September 30th, where a given water year is named for the calendar year on September 30th), the model simulated surface runoff with a Nash–Sutcliffe efficiency (NSE) of 0.7, periodic soil water content (comparison to seasonal soil core measurements) with a root mean square error (RMSE) ≤0.05 m3 m?3, and continuous soil water content (comparison to in situ soil sensors) at 15 of 20 microsites with NSE ≥0.4. The model predicted 2013 field variability in winter wheat yield with RMSE of 1100 kg ha?1. Simulated uniform N management resulted in 0–35 kg ha?1 greater field average yield in comparison to variable-rate management. The savings in fertilizer costs under variable-rate N management resulted in $23–$32 ha?1 greater field average returns to risk. This study demonstrated the capacity of CS-MB to further understanding of simulated and observed field-scale spatial variability and simulated crop response to low, medium and high annual precipitation.  相似文献   

12.
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13.
Wheat field seedling density has a significant impact on the yield and quality of grains. Accurate and timely estimates of wheat field seedling density can guide cultivation to ensure high yield. The objective of this study was to develop an image-processing based, automatic counting method for wheat field seedlings, to investigate the principle of automatic counting of wheat emergence in the field, and to validate the newly developed method in various conditions. Digital images of the wheat fields at seedling stages with five cultivars and five seedling densities were acquired directly from above the fields. The wheat seedlings information was extracted from the background using excessive green and Otsu’s method. By analyzing the characteristic parameters of the overlapping regions (Overlapping region is a number of overlapping wheat seedlings in the image) of the fields, a chain code-based skeleton optimization method and corresponding equation were established for automatic counting of wheat seedlings in the overlapping regions. The results showed that the newly developed method can effectively count the number of wheat seedlings, with an average accuracy rate of 89.94 % and a highest accuracy rate of 99.21 %. The results also indicated that the accuracy of counting was not affected by different cultivars. However, the seedling density had significant impact on the counting accuracy (P < 0.05). When the seedling density was between 120 × 104 and 240 × 104 ha?1, high counting accuracy (>92 %) could be obtained. The study demonstrated that the newly developed method is reliable for automatic wheat seedlings counting, and also provides a theoretical perspective for automatic seedling counting in the wheat field.  相似文献   

14.
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15.
旱地土壤有机碳氮和供氮能力对长期不同氮肥用量的响应   总被引：2，自引：0，他引：2  
【目的】揭示旱地土壤有机碳氮、氮素矿化对长期不同氮肥用量的响应及有机碳氮与氮素矿化的关系,进而评价土壤供氮能力,为旱地土壤氮素管理提供参考。【方法】在陕西杨凌2004年开始的旱地小麦氮肥长期定位试验基础上,采集不同氮肥用量(0(N0)、160(N160)、320(N320)kg N·hm~(-2))试验的土壤样品,测定土壤有机碳、有机氮,微生物量碳、氮含量,并采用间歇淋洗好气培养法测定土壤的氮素矿化。【结果】与对照N0相比,施用氮肥(N160、N320)增加了0—10、10—20、20—40、0—40 cm土层有机碳含量,且在小麦播前期和收获期表现不一致;施氮(N160和N320)处理均显著提高了0—10 cm土层有机氮含量,但仅N320处理显著提高了0—40 cm土层土壤有机氮含量;施用氮肥(N160、N320)未改变0—10、10—20 cm土层土壤微生物量氮和微生物量碳含量,仅N320处理显著提高了20—40、0—40 cm土层微生物量氮和微生物量碳含量。0—10 cm土层,土壤氮素矿化量、矿化势(N_0)与施氮量、有机氮含量呈显著正相关,氮素矿化速率常数(k)则与其呈显著负相关。10—20 cm土层,施氮处理(N160、N320)土壤的氮素矿化量均显著高于不施氮处理(N0),增幅分别为27.3%和35.2%,且与施氮量、有机碳、有机氮含量呈显著正相关;氮素矿化势(N_0)随着有机碳增加而显著增加,矿化速率常数(k)则降低。20—40 cm土层,N320能提高氮素矿化量,并与有机氮、微生物量碳呈显著正相关。【结论】合理施氮肥能明显促进旱地0—10和10—20 cm土壤有机碳、有机氮积累,提高土壤氮素矿化能力,降低氮素矿化速率,是提高旱地土壤有机氮、有机碳含量和土壤供氮能力的有效途径。  相似文献   

16.
苏南麦田基施包膜尿素的农学和环境效应评价   总被引：1，自引：0，他引：1  
为验证包膜尿素一次性基施、速效矿质氮肥分次施用在南方冬小麦系统中的可替代性,在江苏江宁麦田建立田间试验,通过连续3 a的3个作物季观测,比较了0、160 kg N·hm~(-2)(低量)和240 kg N·hm~(-2)(习惯用量)施氮量下树脂包膜尿素一次基施(PU)和非包膜尿素分次施用(U)对小麦产量、氮肥利用率及NH_3挥发与N_2O排放的影响,并从经济效益和气态活性氮减排两方面评估了包膜尿素施用的农学和环境效应。结果表明:U和PU处理小麦产量均随施氮量增加而提高,但PU下增产更显著。习惯施氮量下,PU比U平均增加小麦产量16.6%,提高氮肥偏生产力和农学利用效率16.7%和26.6%。等氮量下PU虽不能提高氮肥生理效率,但却显著提高氮肥利用率35.7%～65.2%。同时,PU较U处理能有效削减NH_3和N_2O排放峰,习惯施氮量下可降低NH_3和N_2O季节累积排放量43.3%和37.6%。综合分析产量、肥料和其他管理成本的产投收益结果表明,施用160 kg N·hm~(-2)PU即可近似达到U习惯施氮量下小麦产量水平和净收益;且当PU施氮量增至240 kg N·hm~(-2)时,可在不显著增加NH_3和N_2O排放情况下,显著增加小麦产量,近而大幅提高农户净收益41.8%。研究表明,与农户习惯施氮相比,供试聚氨酯包膜尿素一次基施不仅能够获得高产,而且也有利于农户增收和环境保护。  相似文献   

17.
Spatial and temporal variability of soil nitrogen (N) supply together with temporal variability of plant N demand make conventional N management difficult. This study was conducted to determine the impact of residual soil nitrate-N (NO3-N) on ground-based remote sensing management of in-season N fertilizer applications for commercial center-pivot irrigated corn (Zea mays L.) in northeast Colorado. Wedge-shaped areas were established to facilitate fertigation with the center pivot in two areas of the field that had significantly different amounts of residual soil NO3-N in the soil profile. One in-season fertigation (48 kg N ha−1) was required in the Bijou loamy sand soil with high residual NO3-N versus three in-season fertigations totaling 102 kg N ha−1 in the Valentine fine sand soil with low residual NO3-N. The farmer applied five fertigations to the field between the wedges for a total in-season N application of 214 kg N ha−1. Nitrogen input was reduced by 78% and 52%, respectively, in these two areas compared to the farmer’s traditional practice without any reductions in corn yield. The ground-based remote sensing management of in-season applied N increased N use efficiency and significantly reduced residual soil NO3-N (0–1.5 m depth) in the loamy sand soil area. Applying fertilizer N as needed by the crop and where needed in a field may reduce N inputs compared to traditional farmer accepted practices and improve in-season N management.  相似文献   

18.
海河低平原渠灌区麦田深松的节水增产效应研究   总被引：7，自引：1，他引：6  
【目的】研究海河低平原渠灌区土壤深松对冬小麦的节水增产效应,以提高冬小麦产量和水分利用效率。【方法】于2011-2012年和2012-2013年冬小麦生长季,以冬小麦品种良星99为材料,大田条件下,通过小麦季设置旋耕（RT）、深松（SRT）和深耕（MRT）3种耕作方式处理,在海河低平原渠灌区进行了2个周期的研究。【结果】（1）深松可提高土壤水分入渗速率。水分入渗速率稳定时,深松处理土壤水分入渗速率为0.05 mm·s-1,分别是旋耕处理和深耕处理的2.50倍和1.67倍。（2）渠灌条件下,深松有利于水分在土壤中快速下渗,优化水分在深层土壤中的分布,提升深层土壤对灌水的储蓄能力。灌水后48 h,在0-180 cm土层,深松处理土壤水分增量为158.5 mm,旋耕和深耕处理分别为142.5和144.1 mm,分别相当于深松处理的89.9%和90.9%。（3）在冬小麦冬前阶段,深耕处理棵间蒸发量最高,分别是深松和旋耕处理的1.15倍和1.35倍。冬小麦返青后,旋耕处理棵间蒸发量提高,尤其是春季灌水后,旋耕处理日棵间蒸发量上升更快,最高达1.32 mm·d-1,而深松处理和深耕处理则仅为0.78和0.85 mm·d-1。深松处理全生育期棵间蒸发量最低,仅为138.17 mm,分别相当于深耕处理和旋耕处理的86.9%和89.7%。（4）冬小麦播种至拔节期,旋耕处理0-100 cm土层含水量高于深松和深耕处理;拔节期至成熟,0-20 cm土层,旋耕处理含水量最高;20-80 cm土层,深松处理含水量最高;80 cm以下土层,3个处理差异不显著。（5）深松处理生育期耗水量为419.1 mm,比旋耕和深耕处理节水约6%;深松处理对灌水和降水的消耗比例分别为41.2%和22.0%,显著高于深耕和旋耕处理。（6）深松处理产量平均为8 550 kg·hm-2,分别比旋耕和深耕处理提高15.4%和6.9%,其水分利用效率比旋耕和深耕处理分别高22.9%和14.0%。【结论】土壤深松可增加麦田地表水入渗速率,减少灌水和降水的无效蒸发,提高土壤对灌水和降水的储蓄,降低冬小麦耗水量,提高其水分利用效率和灌水生产效率,最终显著提高冬小麦产量,具有较好的节水增产效应。建议在海河低平原渠灌区冬小麦种植中采用深松耕作措施。  相似文献   

19.
In-season site-specific nitrogen (N) management is a promising strategy to improve crop N use efficiency and reduce risks of environmental contamination. To successfully implement such precision management strategies, it is important to accurately estimate yield potential without additional topdressing N application (YP0) as well as precisely assess the responsiveness to additional N application (RI) during the growing season. Previous research has mainly used normalized difference vegetation index (NDVI) or ratio vegetation index (RVI) obtained from GreenSeeker active crop canopy sensor with two fixed bands in red and near-infrared (NIR) spectrums to estimate these two parameters. The development of three-band Crop Circle active sensor provides a potential to improve in-season estimation of YP0 and RI. The objectives of this study were twofold: (1) identify important vegetation indices obtained from Crop Circle ACS-470 sensor for estimating rice YP0 and RI; and (2) evaluate their potential improvements over GreenSeeker NDVI and RVI. Four site-years of field N rate experiments were conducted in 2012 and 2013 at the Jiansanjiang Experiment Station of China Agricultural University located in Northeast China. The GreenSeeker and Crop Circle ACS-470 active canopy sensor with green, red edge, and NIR bands were used to collect rice canopy reflectance data at different key growth stages. The results indicated that both the GreenSeeker (best R2 = 0.66 and 0.70, respectively) and Crop Circle (best R2 = 0.71 and 0.77, respectively) sensors worked well for estimating YP0 and RI at the stem elongation stage. At the booting stage, Crop Circle red edge optimized soil adjusted vegetation index (REOSAVI, R2 = 0.82) and green ratio vegetation index (R2 = 0.73) explained 26 and 22 % more variability in YP0 and RI, respectively, than GreenSeeker NDVI or RVI. At the heading stage, the GreenSeeker sensor indices became saturated and consequently could not be used for YP0 or RI estimation, while Crop Circle REOSAVI and normalized green index could still explain more than 70 % of YP0 and RI variability. It is concluded that both sensors performed similarly at the stem elongation stage, but significantly better results were obtained by the Crop Circle sensor at the booting and heading stages. Furthermore, the results revealed that Crop Circle green band-based vegetation indices performed well for RI estimation while the red edge-based vegetation indices were the best for estimating YP0 at later growth stages.  相似文献   

20.
不同供氮水平下小麦品种的氮效率差异及其氮代谢特征   总被引：10，自引：2，他引：8  
【目的】明确不同氮肥生理利用率小麦品种的氮代谢差异,为小麦高产及合理施肥提供理论依据,实现小麦节氮增产。【方法】采用大田试验方法,从16个小麦品种中筛选出氮素利用效率差异显著的低氮高效型小麦品种漯麦18、豫麦49-198和低氮低效型品种西农509、豫农202。然后进一步分析两类品种在N0（CK）,N120（120 kg·hm-2）和N225（225 kg·hm-2）3个供氮水平下各小麦品种的产量、叶片GS活性、可溶性蛋白、游离氨基酸、NO3-及全氮含量等氮代谢指标的差异。【结果】不同供氮水平下,氮肥生理利用率、产量、地上部及籽粒氮素积累量和叶片的GS活性、硝态氮含量、游离氨基酸含量、可溶性蛋白含量、全氮含量等均表现为低氮高效品种漯麦18、豫麦49-198显著高于低氮低效品种西农509、豫农202。增加供氮量,两类品种的产量、地上部及籽粒氮素积累量和叶片GS活性等氮代谢同化物指标均增加,而氮肥生理利用率降低。但两类品种对供氮水平响应不同,与N0相比,增加供氮量,低氮低效品种西农509、豫农202地上部及籽粒氮积累量、叶片的GS活性、硝态氮含量、游离氨基酸含量、可溶性蛋白含量、全氮含量的增幅均高于低氮高效品种漯麦18、豫麦49-198,但是,产量的增幅却显著低于低氮高效品种;氮肥生理利用率的降幅则以低氮高效品种显著高于低氮低效品种。【结论】低氮高效品种漯麦18、豫麦49-198相对于低氮低效品种西农509、豫农202具有更高的产量及氮素利用效率是因为其具有较高的GS活性,从而促进了植株对氮素的吸收与同化,使整个氮代谢过程利用效率提高,获得更高产量。低氮高效品种耐低氮能力较强,增产潜力较大;低氮低效品种对氮肥反应较为敏感,但是其氮素分配利用能力较低。  相似文献   

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